San Dimas City Council
September 24, 2024

4.1 Air Quality
City of San Dimas 4.1-4 Community Development Department Downtown Specific Plan Draft EIR June 2024
Nitrogen Dioxide (NO2)
NO2 is a reddish-brown, highly reactive gas that is formed in the ambient air through the oxidation of nitric oxide (NO). NO2 is also a byproduct of fuel combustion. Population-based health studies suggest that an increase in acute respiratory illness, including infections and respiratory symptoms in children (not infants), is associated with long-term exposures to NO2 at levels found in homes with gas stoves, which are higher than ambient levels found in Southern California. Increase in resistance to air flow and airway contraction is observed after short-term exposure to NO2 in healthy individuals. Larger decreases in lung functions are observed in individuals with asthma or chronic obstructive pulmonary disease (e.g., chronic bronchitis, emphysema) than in healthy individuals, indicating a greater susceptibility of these sub-groups.

In animals, exposure to levels of NO2 considerably higher than ambient concentrations result in increased susceptibility to infections, possibly due to the observed changes in cells involved in maintaining immune functions. The severity of lung tissue damage associated with high levels of ozone exposure increases when animals are exposed to a combination of O3 and NO2.

A detailed discussion of the health effects of NO2 is provided in the SCAQMD Final 2022 Air Quality Management Plan.1
Particulate Matter (PM10 and PM2.5)
A consistent correlation between elevated ambient respirable and fine particulate matter (PM10 and PM2.5) levels and an increase in mortality rates, respiratory infections, number and severity of asthma attacks, and the number of hospital admissions has been observed in different parts of the US and various areas around the world. In recent years, some studies have reported an association between long-term exposure to air pollution dominated by fine particles and increased mortality, reduction in life span, and an increased mortality from lung cancer.

Daily fluctuations in fine-particulate-matter concentration levels have also been related to hospital admissions for acute respiratory conditions in children, to school and kindergarten absences, to a decrease in respiratory lung volumes in normal children and to increased medication use in children and adults with asthma. Recent studies show lung function growth in children is reduced with long-term exposure to particulate matter. The elderly, people with pre-existing respiratory or cardiovascular disease, and children appear to be more susceptible to the effects of PM10 and PM2.5. 1 South Coast Air Quality Management District(SCAQMD), Final 2022 Air Quality Management Plan, Appendix I: Health Effects, http://www.aqmd.gov/docs/default-source/clean-air-plans/air-quality-management-plans/2022-air-qualitymanagement-plan/final-2022-aqmp/final-2022-aqmp.pdf?sfvrsn=16. Accessed July 2023.

4.1 Air Quality
City of San Dimas 4.1-5 Community Development Department Downtown Specific Plan Draft EIR June 2024
Sulfur Dioxide (SO2)
SO2 is a colorless, extremely irritating gas or liquid. It enters the atmosphere as a pollutant mainly as a result of burning high sulfur-content fuel oils and coal, as well as from chemical processes occurring at chemical plants and refineries. When SO2 oxidizes in the atmosphere, it forms sulfates (SO4). Collectively, these pollutants are referred to as sulfur oxides (SOx).

A few minutes of exposure to low levels of SO2 can result in airway constriction in some asthmatics, all of whom are sensitive to its effects. Asthmatics’ acute exposure to SO2 increases their resistance to air flow and reduces their breathing capacity, which leads to severe breathing difficulties. In contrast, healthy individuals do not exhibit similar acute responses even after exposure to higher concentrations of SO2.

Animal studies suggest that despite the fact that SO2 is a respiratory irritant, it does not cause substantial lung injury at ambient concentrations. However, very high levels of exposure can cause lung edema (fluid accumulation), lung tissue damage, and sloughing off cells lining the respiratory tract.

Some population-based studies indicate that the mortality and morbidity effects associated with fine particles show a similar association with ambient SO2 levels. In these studies, efforts to separate the effects of SO2 from those of fine particles have not been successful. It is not clear whether the two pollutants act synergistically, or one pollutant alone is the predominant factor.

Most of the health effects associated with fine particles and SO2 are also associated with SO4. Both mortality and morbidity effects have been observed with an increase in ambient SO4 concentrations.

However, efforts to separate the effects of SO4 from the effects of other pollutants have generally not been successful. Clinical studies of asthmatics exposed to sulfuric acid suggest that adolescent asthmatics are possibly a subgroup susceptible to acid aerosol exposure. Animal studies suggest that acidic particles, such as sulfuric acid aerosol and ammonium bisulfate, are more toxic than nonacidic particles like ammonium sulfate. Whether effects are attributable to acidity or to particles remains unresolved.

Lead (Pb)
Pb occurs in the atmosphere as particulate matter. The combustion of leaded gasoline is the primary source of airborne Pb in the SCAB. The use of leaded gasoline is no longer permitted for on-road motor vehicles, so the majority of such combustion emissions are associated with off-road vehicles, such as racecars and some aircraft. However, because leaded gasoline was emitted in large amounts from vehicles when leaded gasoline was used for on-road motor vehicles, Pb is present in many urban soils and can be resuspended in the air. Other sources of Pb include the manufacturing and recycling of batteries, paint, ink, ceramics, ammunition, and the use of secondary lead smelters. Pb is also found in lead-based paint, which is considered a health hazard for people, especially children. From the turn of the century through

4.1 Air Quality
City of San Dimas 4.1-6 Community Development Department Downtown Specific Plan Draft EIR June 2024
the 1940s, paint manufacturers used lead as a primary ingredient in many oil-based paints. Use of lead in paint decreased but was still used until 1978 when it was banned from residential use. Remodeling, renovations, or demolition activities in older buildings could disturb lead-based paint surfaces.

Fetuses, infants, and children are more sensitive than others to the adverse effects of lead exposure.

Exposure to low levels of lead can adversely affect the development and function of the central nervous system, leading to learning disorders, distractibility, inability to follow simple commands, and lower intelligence levels. In adults, increased lead levels are associated with increased blood pressure.

Lead poisoning can cause anemia, lethargy, seizures, and death. It appears that there are no direct effects of lead on the respiratory system. Lead can be stored in the bone from early-age environmental exposure, and elevated blood lead levels can occur due to the breakdown of bone tissue during pregnancy, hyperthyroidism (increased secretion of hormones from the thyroid gland) and osteoporosis (breakdown of bony tissue). Fetuses and breast-fed babies can be exposed to higher levels of lead because of previous environmental lead exposure of their mothers.

Volatile Organic Compounds (VOCs)
VOC means any compound of carbon, excluding carbon monoxide, carbon dioxide (CO2), carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions and thus, a precursor of ozone formation. VOC emissions often result from the evaporation of solvents in architectural coatings. VOC are any reactive compounds of carbon, excluding methane, CO, CO2 carbonic acid, metallic carbides or carbonates, ammonium carbonate, and other exempt compounds. VOC emissions are generated from the exhaust of mobile sources.2 Both VOC and ROGs are precursors to ozone and the terms can be used interchangeably.3 Toxic Air Contaminants (TACs)
TACs refer to a diverse group of “non-criteria” air pollutants that can affect human health but have not had ambient air quality standards established for them. This is not because they are fundamentally different from the pollutants discussed previously, but because their effects tend to be local rather than regional. TACs are classified as carcinogenic and noncarcinogenic, where carcinogenic TACs can cause cancer and noncarcinogenic TAC can cause acute and chronic impacts to different target organ systems (e.g., eyes, respiratory, reproductive, developmental, nervous, and cardiovascular). 2 SCAQMD, Final 2022 Air Quality Management Plan, Appendix I: Health Effects, http://www.aqmd.gov/docs/defaultsource/clean-air-plans/air-quality-management-plans/2022-air-quality-management-plan/final-2022-aqmp/final-2022- aqmp.pdf?sfvrsn=16. Accessed July 2023.
3 Both VOC and ROGs are both precursors to ozone so they are summed in the CalEEMod report under the header ROG. For the purposes of comparing the ROG value to a VOC significance threshold, the terms can be used interchangeably.

4.1 Air Quality
City of San Dimas 4.1-7 Community Development Department Downtown Specific Plan Draft EIR June 2024
The California Air Resources Board (CARB) and the Office of Environmental Health Hazard Assessment (OEHHA) determine if a substance should be formally identified, or “listed,” as a TAC in California.4 Diesel Particulate Matter (DPM), which is emitted in the exhaust from diesel engines, was listed by the State as a TAC in 1998. DPM has historically been used as a surrogate measure of exposure for all diesel exhaust emissions. DPM consists of fine particles (fine particles have a diameter less than 2.5 microns [μm]), including a subgroup of ultrafine particles (ultrafine particles have a diameter less than 0.1 μm).

Collectively, these particles have a large surface area, which makes them an excellent medium for absorbing organics. The visible emissions in diesel exhaust include carbon particles or “soot.” Diesel exhaust also contains a variety of harmful gases and cancer-causing substances.

Exposure to DPM may be a health hazard, particularly to children whose lungs are still developing and the elderly who may have other serious health problems. DPM levels and resultant potential health effects may be higher near heavily traveled roadways with substantial truck traffic or near industrial facilities.

According to CARB, DPM exposure may lead to the following adverse health effects: (1) aggravated asthma; (2) chronic bronchitis; (3) increased respiratory and cardiovascular hospitalizations; (4) decreased lung function in children; (5) lung cancer; and (6) premature deaths for people with heart or lung disease.5 To provide a perspective on the contribution that DPM has on the overall Statewide average ambient air toxics potential cancer risk, CARB evaluated risks from specific compounds using data from CARB’s ambient monitoring network. CARB maintains 21-site air toxics monitoring network that measures outdoor ambient concentration levels of approximately 60 airborne toxins. CARB has determined that, of the top ten inhalation risk contributors, DPM contributes approximately 68 percent of the total potential cancer risk.6
Valley Fever
Coccidioidomycosis, more commonly known as “Valley Fever,” is primarily a disease of the lungs caused by the spores of the Coccidioides immitis fungus. The spores are found in soils, become airborne when the soil is disturbed, and are subsequently inhaled into the lungs. After the fungal spores have settled in the lungs, they change into a multicellular structure called a spherule. Fungal growth in the lungs occurs as the spherule grows and bursts, releasing endospores, which then develop into more spherules.

Valley Fever symptoms occur within two to three weeks of exposure. Approximately 60 percent of Valley Fever cases are mild and display flu-like symptoms or no symptoms at all. Of those who are exposed and 4 The complete list of such substances is located at www.arb.ca.gov/toxics/id/taclist.htm. 5 California Air Resources Board (CARB), Diesel and Health Research, accessed July 2023, https://ww2.arb.ca.gov/resources/overview-diesel-exhaust-and-health. 6 SCAQMD, “Multiple Air Toxics Exposure Study in the South Coast Air Basin (MATES-IV).” (May 2015), accessed July 2023, http://www.aqmd.gov/docs/default-source/air-quality/air-toxic-studies/mates-iv/mates-iv-final-draft-report-4-1-15.pdf.

4.1 Air Quality
City of San Dimas 4.1-8 Community Development Department Downtown Specific Plan Draft EIR June 2024
seek medical treatment, the most common symptoms include fatigue, cough, loss of appetite, rash, headache, and joint aches. In some cases, painful red bumps may develop on the skin. One important fact to mention is that these symptoms are not unique to Valley Fever and may be caused by other illnesses as well. Identifying and confirming this disease require specific laboratory tests such as: (1) microscopic identification of the fungal spherules in infected tissue, sputum, or body fluid sample; (2) growing a culture of Coccidioides immitis from a tissue specimen, sputum, or body fluid; (3) detection of antibodies (serological tests specifically for Valley Fever) against the fungus in blood serum or other body fluids; and (4) administering the Valley Fever Skin Test (called coccidioidin or spherulin), which indicate prior exposure to the fungus.

Valley Fever is not contagious, and therefore, cannot be passed on from person to person. Most of those who are infected would recover without treatment within six months and would have life-long immunity to the fungal spores. In severe cases, especially in those patients with rapid and extensive primary illness, those who are at risk for dissemination of disease, and those who have disseminated disease, antifungal drug therapy is used. The type of medication used and the duration of drug therapy are determined by the severity of disease and response to the therapy. The medications used include ketoconazole, itraconazole and fluconazole in chronic, mild-to-moderate disease, and amphotericin B, given intravenously or inserted into the spinal fluid, for rapidly progressive disease. Although these treatments are often helpful, evidence of disease may persist, and years of treatment may be required.

The usual course of Valley Fever in healthy people is complete recovery within six months. In most cases, the body’s immune response is effective and no specific course of treatment is necessary. About five percent of cases of Valley Fever result in pneumonia (infection of the lungs), while another five percent of patients develop lung cavities after their initial infection with Valley Fever. These cavities occur most often in older adults, usually without symptoms, and about 50 percent of them disappear within two years.

Occasionally, these cavities rupture, causing chest pain and difficulty breathing, and require surgical repair.

Only one to two percent of those exposed who seek medical attention would develop a disease that disseminates (spreads) to other parts of the body other than the lungs.

Factors that affect the susceptibility to coccidioidal dissemination are race, sex, pregnancy, age, and immunosuppression. While there are no racial or gender differences in susceptibility to primary infection with coccidioidomycosis, differences in risk of disseminated infection do appear to exist. Men have a higher rate of dissemination than do women and several studies have shown that the rate of dissemination in African Americans and Filipinos is several times higher than in the rest of the US population. Native Americans, Hispanics, and Asians may also have a higher rate of dissemination than the general population, but these population differences are not well defined.

4.1 Air Quality
City of San Dimas 4.1-9 Community Development Department Downtown Specific Plan Draft EIR June 2024
The Coccidioides immitis fungal spores are often found in the soil around rodent burrows, Indian ruins, and burial grounds. The spores become airborne when the soil is disturbed by winds, construction, farming, and soil disturbing activities. This type of fungus is endemic to the southwestern United States and Los Angeles County has been identified as an area where the fungus that causes Valley Fever lives.

The Project site is located in an area designated as suspected endemic for Valley Fever by the Center for Disease Control and Prevention (CDC).7 Los Angeles County Public Health (LACPH) indicates that there were 141 cases in the Service Planning Area of the proposed Project in 2022.8 Local Air Quality
For evaluation purposes, SCAQMD has divided its territory into 36 Source Receptor Areas (SRA) with operating monitoring stations in most of the SRAs. These SRAs are designated to provide a general representation of the local meteorological, terrain, and air quality conditions within each geographical area.

The Project Site is located in the SCAB in SRA 10, Pomona/Walnut Valley. The SCAQMD air quality monitoring station closest to the site is the Glendora-Laurel Station located 2.8 miles northwest of the Project at 840 Laurel Avenue, Glendora.9 This station monitors PM10, PM2.5, and Nitrogen Dioxide. The Pomona Station at 924 N. Garey Avenue, Pomona, which is located 3.7 miles southeast, monitors hourly ozone, 8-hourly ozone.10 The air quality trends from these stations are used to represent the ambient air quality in the Project area. The ambient air quality data in Table 4.1-2: Air Quality Monitoring Summary shows that the region has exceeded the O3, PM10, and PM2.5 standards in recent years.

Existing Conditions
The proposed Downtown Specific Plan (DTSP) area is located within the City of San Dimas, within the San Gabriel Valley in the eastern portion of Los Angeles County. The City is surrounded by the Cities of Glendora and Covina, and unincorporated areas of Los Angeles County to the west, the City of La Verne and unincorporated areas of Los Angeles County to the east, the San Gabriel Mountains range to the north, the City of Pomona to the southeast, and the City of Walnut to the southwest. The City is crossed by the 210 (Foothill), 57 (Orange), and 10 (San Bernardino) freeways. Major east-west thoroughfares providing access include Arrow Highway, Foothill Boulevard (Historic Route 66), and Bonita Avenue, on which San 7 Centers for Disease Control and Prevention, Valley Fever Maps, https://www.cdc.gov/fungal/diseases/coccidioidomycosis/maps.html#surveillance, accessed August 2019. 8 Los Angeles County Department of Public Health, Acute Communicable Disease Control, http://publichealth.lacounty.gov/acd/Diseases/Cocci.htm 9 California Air Resources Board, Top 4 Summary: Site Selection, https://www.arb.ca.gov/adam/topfour/topfour2.php.

Accessed September 2023.
10 California Air Resources Board, Top 4 Summary: Site Selection, https://www.arb.ca.gov/adam/topfour/topfour2.php.

Accessed September 2023.

4.1 Air Quality
City of San Dimas 4.1-10 Community Development Department Downtown Specific Plan Draft EIR June 2024
Dimas’ historic downtown is centered. Major north-south thoroughfares include Lone Hill Avenue, the 57 (Orange) Freeway, San Dimas Avenue, Walnut Avenue, and San Dimas Canyon Road.

The City of San Dimas contains a population of approximately 34,000 and is known for its 19th century historical character, its historic downtown core, and its varied residential neighborhoods. The majority of the DTSP area has been previously developed, with uses including commercial, multi-family residential, and public facilities. Between the 57 freeway and North Eucla Avenue, existing uses include highwayoriented commercial, including a hotel, auto-oriented commercial strips, and several big-box retailers.

Between North Eucla Avenue and South Cataract Avenue, there are two vacant properties, a restaurant, a bowling alley, and a small number of professional offices. East of South Cataract Avenue, existing development along Bonita Avenue primarily includes both auto-oriented and street-facing commercial properties, parking lots, and, east of South Walnut Avenue, a small number of multi-family residential properties. A complex of public facilities, including the San Dimas City Hall, the San Dimas Library, and Civic Center Park, is located at the corner of Bonita and South Walnut Avenues. The surrounding area includes residential neighborhoods to the north, the remainder of the Bonita Avenue commercial corridor to the east, industrial, office, and multi-family areas to the south and southwest, and big-box retail commercial shopping areas to the west, opposite the Orange Freeway.

Table 4.1-2: Air Quality Monitoring Summary
Air Pollutant Average Time (Units) 2019 2020 2021
Ozone (O3)
State Max 1 hour (ppm) 0.098 0.180 0.120
Days > CAAQS threshold (0.09 ppm) 3 51 27
National Max 8 hour (ppm) 0.083 0.124 0.092
Days > NAAQS threshold (0.075 ppm) 12 84 41
State Max 8 hour (ppm) 0.084 0.124 0.092
Days > CAAQS threshold (0.07 ppm) 13 88 43
Carbon monoxide (CO) — — —
Nitrogen dioxide (NO2)
National Max 1 hour (ppm) 52.9 50.4 68.6
Days > NAAQS threshold (0.100 ppm) 0 0 0
State Max 1 hour (ppm) 60.0 50.0 60.0
Days > CAAQS threshold (0.18 ppm) 0 0 0
Respirable particulate
matter (PM10)
National Max (µg/m3) 97.9 227.2 121.5
National Annual Average (µg/m3) 21.8 28.0 27.7
Days > NAAQS threshold (150 µg/m3) 0 2 0
State Max (µg/m3) — — —
State Annual Average (µg/m3) — — —
Days > CAAQS threshold (50 µg/m3) — — —

4.1 Air Quality
City of San Dimas 4.1-11 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.1-2: Air Quality Monitoring Summary
Air Pollutant Average Time (Units) 2019 2020 2021
Fine particulate matter
(PM2.5)
National Max (µg/m3) — — —
National Annual Average (µg/m3) — — —
Days > NAAQS threshold (35 µg/m3) — — —
State Max (µg/m3) 75.1 148.1 97.0
State Annual Average (µg/m3) 11.8 14.9 —
Source: California Air Resources Board, Air Quality Monitoring Summary, https://www.arb.ca.gov/adam/topfour/topfour1.php.

Note: (—) = Data not available.

Regulatory Framework
State of California
CARB, a part of the California Environmental Protection Agency (CalEPA), is responsible for the coordination and administration of both State and federal air pollution control programs within California.

In this capacity, CARB conducts research, sets State AAQS, compiles emission inventories, develops suggested control measures, and provides oversight of local programs. CARB establishes emissions standards for motor vehicles sold in California, consumer products, and various types of commercial equipment. It also sets fuel specifications to further reduce vehicular emissions and the CAAQS currently in effect for each of the criteria pollutants, as well as other pollutants recognized by the State. The CAAQS include more stringent standards than the NAAQS. Criteria pollutants that are in nonattainment under the CAAQS include O3, PM2.5, and PM10.

Air Quality and Land Use Handbook
CARB published the Air Quality and Land Use Handbook11 on April 28, 2005, to serve as a general guide for considering health effects associated with siting sensitive receptors proximate to sources of TAC emissions. These recommendations are voluntary and do not constitute a requirement or mandate for either land use agencies or local air districts. The goal of the guidance document is to protect sensitive receptors, such as children, the elderly, acutely ill, and chronically ill persons, from exposure to TAC emissions. Examples of CARB’s siting recommendations include the following: (1) avoid siting sensitive receptors within 500 feet of a freeway, urban road with 100,000 vehicles per day, or rural road with 50,000 vehicles per day; (2) avoid siting sensitive receptors within 1,000 feet of a distribution center (that accommodates more than 100 trucks per day, more than 50 trucks with operating transport refrigeration units per day, or where transport refrigeration unit operations exceed 300 hours per week); and (3) avoid 11 CARB, Air Quality and Land Use Handbook: A Community Health Perspective (April 2005), https://www.arb.ca.gov/ch/handbook.pdf.

4.1 Air Quality
City of San Dimas 4.1-12 Community Development Department Downtown Specific Plan Draft EIR June 2024
siting sensitive receptors within 300 feet of any dry cleaning operation using perchloroethylene and within 500 feet of operations with two or more machines.

Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling (Title 13 of the California Code of Regulations, Section 2485) The Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling12 measure includes regulations that pertain to air quality emissions. Specifically, Section 2485 states that during construction, the idling of all diesel-fueled commercial vehicles weighing more than 10,000 pounds shall be limited to 5 minutes at any location. In addition, Section 93115 in Title 17 of the California Code of Regulations (CCR)13 states that operation of any stationary, diesel-fueled, compression-ignition engines shall meet specified fuel and fuel additive requirements and emission standards.

California Air Resources Board (CARB)
CARB Rule 2449, General Requirements for In-Use Off-Road Diesel-Fueled Fleets Requires off-road diesel vehicles to limit nonessential idling to no more than 5 consecutive minutes.14 CARB Rule 2485, Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling
CARB Rule 2485 requires commercial vehicles weighing more than 10,000 pounds to limit nonessential idling to no more than 5 consecutive minutes.15
Local
South Coast Air Quality Management District
SCAQMD shares responsibility with CARB for ensuring that all State and federal ambient air quality standards are achieved and maintained over an area of approximately 10,743 square miles. This area includes the South Coast Air Basin and portions of the Salton Sea and Mojave Desert Air Basins, all of Orange County, and the non-desert portions of Los Angeles, Riverside, and San Bernardino counties. It does not include the Antelope Valley or the non-desert portion of western San Bernardino County.

SCAQMD is responsible for controlling emissions primarily from stationary sources. SCAQMD maintains air quality monitoring stations throughout the Air Basins. SCAQMD, in coordination with the SCAG, is also 12 CARB, Section 2485 in Title 13 of the CCR, https://www.arb.ca.gov/msprog/truck-idling/13ccr2485_09022016.pdf. 13 CARB, Stationary diesel ATCM), Accessed July 2023.https://ww2.arb.ca.gov/our-work/programs/stationary-dieselatcm#:~:text=Final%20Regulation%20Order%20Amendments%20to,compression%20ignition%20(CI)%20engines. 14 CARB, Final Regulation Order: Regulation for In-Use Off-Road Diesel-Fueled Facts, accessed July 2023, https://ww2.arb.ca.gov/our-work/programs/use-road-diesel-fueled-fleets-regulation 15 SCAQMD, Rule 1113 Architectural Coating (amended September 6, 2013).

4.1 Air Quality
City of San Dimas 4.1-13 Community Development Department Downtown Specific Plan Draft EIR June 2024
responsible for developing, updating, and implementing the AQMP for the Air Basins. An AQMP is a plan prepared and implemented by an air pollution district for a county or region designated as nonattainment of the national and/or California ambient air quality standards.

The SCAQMD adopted the Final 2022 AQMP on December 2, 2022.16 The 2022 AQMP includes transportation control measures developed by SCAG from the 2020 Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS), as well as the integrated strategies and measures needed to meet the NAAQS. The 2022 AQMP includes strategies to meet the 8-hour ozone NAAQS as well as the latest 24-hour and annual PM2.5 standards.

Under the Federal CAA, SCAQMD has adopted federal attainment plans for O3 and PM10. The SCAQMD reviews projects to ensure that they would not (1) cause or contribute to any new violation of any air quality standard; (2) increase the frequency or severity of any existing violation of any air quality standard; or (3) delay the timely attainment of any air quality standard or any required interim emission reductions or other milestones of any federal attainment plan.

The SCAQMD is responsible for limiting the number of emissions that can be generated throughout the Basin by various stationary, area, and mobile sources. Specific rules and regulations have been adopted by the SCAQMD Governing Board. These rules and regulations limit the emissions that can be generated by various uses or activities and identify specific pollution reduction measures, which must be implemented in association with various uses and activities. These rules not only regulate the emissions of the federal and State criteria pollutants, but also toxic air contaminants and acutely hazardous materials. The rules are also subject to ongoing refinement by SCAQMD.

Among the SCAQMD rules applicable to the Project are Rule 212 (Standards for Approving Permits and Issuing Public Notice), Rule 403 (Fugitive Dust), Rule 1113 (Architectural Coatings), Rule 1401 (New Source Review of Toxic Air Contaminants), and Regulation XIII (New Source Review). Rule 212 states that the Executive Officer has the power to deny a Permit to Construct or Permit to Operate based on standard operating procedures and required notifications. Rule 403 requires the use of stringent best available control measures to minimize PM10 emissions during grading and construction activities. Rule 1113 requires reductions in the VOC content of coatings, with a substantial reduction in the VOC content limit for specified types of coatings. Rule 1401 requires limits for maximum individual cancer risk, cancer burden, and noncancer acute and chronic hazard index from new permit units, relocations, or modifications to existing permit units which emit toxic air contaminants. Regulation XIII requires new onsite facility nitrogen dioxide emissions to be minimized through the use of emission control measures (e.g., 16 SCAQMD, Air Quality Management Plan (2022), http://www.aqmd.gov/home/air-quality/clean-air-plans/air-quality-mgtplan. Accessed July 2023.

4.1 Air Quality
City of San Dimas 4.1-14 Community Development Department Downtown Specific Plan Draft EIR June 2024
use of best available control technology for new combustion such as boilers, emergency generators, and water heaters).

City of San Dimas
Local jurisdictions have the authority and responsibility to reduce air pollution through their police power and decision-making authority. Specifically, the City is responsible for the assessment and mitigation of air pollutant emissions resulting from its land use decisions. The City is also responsible for the implementation of transportation control measures as outlined in the AQMP. Examples of such measures include bus turnouts, energy-efficient streetlights, and synchronized traffic signals. In accordance with CEQA requirements and the CEQA review process, the City assesses the air quality impacts of new development projects, requires mitigation for significant air quality impacts by conditioning discretionary permits and monitors and enforces implementation of such mitigation. The City does not, however, have the expertise to develop plans, programs, procedures, and methodologies to ensure that air quality within the City and region would meet federal and State standards. Instead, the City relies on the expertise of the SCAQMD and utilizes the CEQA Air Quality Handbook as the guidance document for the environmental review of plans and development proposals within its jurisdiction.

4.1.3 IMPACT ANALYSIS
Under CEQA, SCAQMD is a commenting agency on air quality within its jurisdiction or impacting its jurisdiction. Under the Federal CAA, SCAQMD has adopted federal attainment plans for O3, PM2.5, and PM10. SCAQMD reviews projects to ensure that they would not: (1) cause or contribute to any new violation of any air quality standard; (2) increase the frequency or severity of any existing violation of any air quality standard; or (3) delay timely attainment of any air quality standard or any required interim emission reductions or other milestones of any federal attainment plan.

Daily Emissions Thresholds
SCAQMD has identified thresholds to determine the significance of both local air quality impacts and impacts to regional air quality for construction activities and project operation, as shown in Table 4.1-3:

Mass Daily Emissions Thresholds.

Table 4.1-3: Mass Daily Emissions Thresholds
Pollutant
Construction Operational
pounds/day
Volatile Organic Compounds (VOC) 75 55

4.1 Air Quality
City of San Dimas 4.1-15 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.1-3: Mass Daily Emissions Thresholds
Pollutant
Construction Operational
pounds/day
Nitrogen dioxide (NOx) 100 55
Carbon monoxide (CO) 550 550
Sulfur dioxide (SOx) 150 150
Respirable particulate matter (PM10) 150 150
Fine particulate matter (PM2.5) 55 55
__________
Source: SCAQMD, CEQA Air Quality Handbook (November 1993), accessed July 2023, https://www.aqmd.gov/docs/defaultsource/ceqa/handbook/scaqmd-air-quality-significance-thresholds.pdf.

Localized Significance Thresholds
The local significance thresholds are based on the SCAQMD Final Localized Significance Threshold (LST) Methodology (LST Methodology)17 guidance document for short-duration construction activities. The SCAQMD recommends the evaluation of localized air quality impacts to sensitive receptors in the immediate vicinity of the Project Site because of construction activities. The SCAQMD provides voluntary guidance on the evaluation of localized air quality impacts to public agencies conducting environmental review of projects located within its jurisdiction. Localized air quality impacts are evaluated by examining the on-site generation of pollutants and their resulting downwind concentrations. For construction, pollutant concentrations are compared to significance thresholds for particulates (PM10 and PM2.5), CO, and NO2. The significance threshold for PM10 represents compliance with SCAQMD Rule 403 (Fugitive Dust). The threshold for PM2.5 is designed to limit emissions and to allow progress toward attainment of the AAQS. Thresholds for CO and NO2 represent the allowable increase in concentrations above background levels that would not cause or contribute to an exceedance of their respective AAQS.

The LST Methodology provides lookup tables of emissions that are based on construction projects of up to 5 acres in size. These LST lookup tables were developed to assist lead agencies with a simple tool for evaluating the impacts from small typical projects. Ambient conditions for Pomona/Walnut Valley, as recorded in SRA 10 by the SCAQMD, were used for ambient conditions in determining appropriate 17 South Coast Air Quality Management District, Final Localized Significance Threshold (LST) Methodology, (June 2003, rev.

July 2008).

4.1 Air Quality
City of San Dimas 4.1-16 Community Development Department Downtown Specific Plan Draft EIR June 2024
threshold levels. Thresholds for each criteria pollutant for construction activity and Project operation are listed in Table 4.1-4: Localized Significance Thresholds.

Table 4.1-4: Localized Significance Thresholds
Pollutant
Construction Operational
pounds/day
Nitrogen dioxide (NO2) 236 236
Carbon monoxide (CO) 1,566 1,566
Respirable particulate matter (PM10) 12 3
Fine particulate matter (PM2.5) 7 2
__________
Notes: Based on a distance to sensitive receptors of 25 meters (82 feet). SCAQMD’s Localized Significance Threshold (LST) Methodology for CEQA Evaluations guidance document provides that projects with boundaries located closer than 25 meters to the nearest receptor should use the LSTs for receptors located at 25 meters.

LST values for 5-acre site.

CO Hotspot
The significance of localized project impacts depends on whether ambient CO levels in the vicinity of the proposed Project are above or below State and federal CO standards. If the Project causes an exceedance of either the State 1-hour or 8-hour CO concentrations, the Project would be considered to have a significant local impact. If ambient levels already exceed a State or federal standard, then project emissions are considered significant if they increase 1-hour CO concentrations by 1.0 parts per million (ppm) or more, or 8-hour CO concentrations by 0.45 ppm or more pursuant to SCAQMD Rule 1303(b).

Cumulative
SCAQMD’s CEQA Air Quality Handbook identifies several methods to determine the cumulative significance of land use projects (i.e., whether the contribution of a project is cumulatively considerable).

However, SCAQMD no longer recommends the use of these methodologies. Instead, SCAQMD recommends that any construction-related emissions and operational emissions from individual development projects that exceed the project-specific mass daily emissions thresholds identified previously also can be considered cumulatively considerable.18 SCAQMD neither recommends quantified 18 “White Paper on Regulatory Options for Addressing Cumulative Impacts from Air Pollution Emissions,” SCAQMD Board Meeting, September 5, 2003, Agenda No. 29, Appendix D, D-3.

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City of San Dimas 4.1-17 Community Development Department Downtown Specific Plan Draft EIR June 2024
analyses of the emissions generated by a set of cumulative development projects, nor provides thresholds of significance to be used to assess the impacts associated with these emissions.

Methodology
The DTSP is a planning document proposed to guide development within the proposed specific plan area; no specific development projects are proposed at this time. Accordingly, a program level analysis of the potential air quality impacts that may result from future development may be facilitated by the DTSP is provided.

Air pollutant emissions would result from construction and operation of subsequent individual development projects within the DTSP. The analysis methodologies for all potential sources of air emissions associated with the proposed DTSP are discussed below.

Emissions Inventory Modeling
The California Emissions Estimator Model, known as CalEEMod, is the CARB–approved computer program model recommended by SCAQMD for use in the quantification of air quality emissions. CalEEMod was developed under the auspices of SCAQMD, with input from other California air districts. CalEEMod utilizes widely accepted models for emissions estimates combined with appropriate data that can be used if sitespecific information is not available. For example, CalEEMod incorporates USEPA-developed emission factors; CARB’s on-road and off-road equipment emission models, such as EMFAC and OFFROAD;19 and studies commissioned by other California agencies, such as the California Energy Commission and CalRecycle.

CalEEMod provides a platform to calculate both construction emissions and operational emissions from a land use development project. Emission sources covered by CalEEMod model include the following:
• One-time construction emissions associated with demolition, grading, utility installation, building, application of architectural coatings (e.g., paint), and paving from emission sources that include both off-road construction equipment and on-road mobile equipment associated with workers, hauling, and the delivery of construction materials to the Project Site. Construction emissions associated with dust control and disposal of waste at landfills are also included in the CalEEMod model. • Operational emissions associated with the occupancy of development, such as on-road mobile vehicle traffic generated by the land uses; off-road emissions from landscaping equipment; energy (i.e., electricity and natural gas) and water usage in the buildings; and emissions from painting operations. 19 EMFAC is an emissions factor model used to calculate emissions rates from on-road vehicles (e.g., passenger vehicles; haul trucks). OFFROAD is an emissions factor model used to calculate emission rates from off-road mobile sources (e.g., construction equipment). CalEEMod version 2022.1 utilizes CARB’s 2021 version of EMFAC.

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City of San Dimas 4.1-18 Community Development Department Downtown Specific Plan Draft EIR June 2024
The disposal of solid waste generated during the postconstruction use of the buildings is also included in the CalEEMod model.

CalEEMod version 2022.1.1.14 was used to quantify the proposed Project’s air quality pollutants. Proposed Project development would generate air pollutants from a number of individual sources during both construction and postconstruction (operational) use of the buildings and related activities.

For purposes of analysis, the mix of development from Table 2.0-2 in Section 2.4: Development Potential was assumed as a projection of the development that may occur over an approximately 20-year period and was used to estimate construction and operational emissions.

Construction Emissions
Construction of individual development projects within the DTSP has the potential to generate temporary criteria pollutant emissions through the use of heavy-duty construction equipment and through vehicle trips generated from workers and haul trucks traveling to and from the Project Site. In addition, fugitive dust emissions would result from soil-handling activities. Mobile-source emissions, primarily NOx, would result from the use of construction equipment, such as dozers and loaders. Construction emissions can vary substantially from day to day, depending on the level of activity, the specific type of construction activity, and prevailing weather conditions.

Daily regional emissions during construction are forecasted by assuming a conservative estimate of construction activities (i.e., assuming all construction occurs at the earliest feasible date) and applying the mobile source and fugitive dust emissions factors. CalEEMod is based on outputs from the CARB off-road emissions model (OFFROAD) and the CARB on-road vehicle emissions model (EMFAC), which are emissions estimation models developed by CARB and used to calculate emissions from construction activities, including on- and off-road vehicles. The input values used in this analysis are based on conservative assumptions in CalEEMod, with appropriate, Project-specific adjustments based on equipment types and expected construction activities. These values were then applied to the construction phasing assumptions used in the criteria pollutant analysis to generate criteria pollutant emissions values for each construction activity.

Operational Emissions
Operation of the Project has the potential to generate criteria pollutant emissions through vehicle trips traveling to and from the Project Site. In addition, emissions would result from area sources on site, such as natural gas combustion, landscaping equipment, and use of consumer products.

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City of San Dimas 4.1-19 Community Development Department Downtown Specific Plan Draft EIR June 2024
Operational emissions were estimated using the CalEEMod software, which was used to forecast the daily regional emissions from area sources that would occur during long-term Project operations. In calculating mobile-source emissions, CalEEMod calculates the emissions associated with on-road mobile sources associated with residents, workers, customers, and delivery vehicles visiting the proposed land uses.

CalEEMod defaults were used to estimate the air quality emissions related to mobile uses due to the nature of the Downtown Specific Plan.

Localized Significance Emissions
Localized air quality impacts are evaluated by examining the on-site generation of pollutants and their resulting downwind concentrations. Emissions were estimated using the CalEEMod software. The LST mass rate look-up tables are applicable to the following pollutants only: NOx, CO, PM10, and PM2.5. LSTs are derived based on the location of the activity (i.e., the source/receptor area); the emission rates of NOX, CO, PM2.5, and PM10; and the distance to the nearest exposed individual. The location of the activity and the distance to the nearest exposed individual can be determined by maps, aerial and site photos, or site visits.
a. Would the project conflict with or obstruct implementation of the applicable air quality plan? Consistency with the Air Quality Management Plan
A consistency determination with regard to the SCAQMD’s AQMP plays an important role in local agency project review by linking local planning and individual projects to the AQMP. In accordance with the procedures established in the SCAQMD’s CEQA Air Quality Handbook,20 the analysis below addresses the criteria identified by the SCAQMD to determine the proposed Project’s consistency with SCAQMD and SCAG air quality related policies.
• Will the project result in any of the following:
− Increase the frequency or severity of existing air quality violations? − Cause or contribute to new air quality violations?
Delay the timely attainment of the air quality standards or the interim emission reductions According to the South Coast Air Quality Management District’s CEQA Handbook, the consistency determination based on the first criterion pertains to ambient pollutant concentrations, rather than to total regional emissions, thus, requiring an analysis of the proposed Project’s pollutant emissions relative to localized pollutant 20 SCAQMD, CEQA Air Quality Handbook (April 1993), p. 12-3.

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City of San Dimas 4.1-20 Community Development Department Downtown Specific Plan Draft EIR June 2024
concentrations.21 A complete review of the proposed Project’s potential impact on ambient pollutant concentrations during construction and operation is provided below.

Regional Emissions
It is mandatory for all construction projects in the SCAB to comply with SCAQMD Rule 403 for fugitive dust.

Rule 403 control requirements include measures to prevent the generation of visible dust plumes.

Measures include, but are not limited to, applying soil binders to uncovered areas, reestablishing ground cover as quickly as possible, utilizing a wheel washing system or other control measures to remove bulk material from tires and vehicle undercarriages before vehicles exit the Project Site, and maintaining effective cover over exposed areas. In addition, SCAQMD Rule 1113 would limit the VOC content of architectural coatings. Thus, compliance with these SCAQMD rules would further reduce construction related regional emissions.

Potential construction-related emissions of criteria air pollutants and precursors were modeled in accordance with SCAQMD-recommended methodologies. Project-specific data (e.g., construction schedule, equipment types and number requirements, and maximum daily acreage disturbed) is not available at this time. Potential emissions from projected development in the DTSP Area was modeled based on the proposed land uses, projected daily trips and default CalEEMod settings and parameters attributable to the construction period and site location.

Table 4.1-5: Project Construction Diesel Equipment Inventory displays the construction equipment required for each activity. The forecast of emissions generated during Proposed Project construction is based on assumptions regarding the type and number of off-road equipment operating.

Table 4.1-5: Project Construction Diesel Equipment Inventory Phase Off-Road Equipment Type Amount Daily
Hours
Horsepower[HP]
(Load Factor)
Demolition
Concrete/Industrial Saws 1 8 33 (0.73)
Excavators 3 8 36 (0.38)
Rubber Tired Dozers 2 8 367 (0.40)
Site Preparation
Rubber Tired Dozers 3 8 367 (0.40)
Tractors/Loaders/Backhoes 4 8 84 (0.37)
Grading
Excavators 2 8 36 (0.38)
Graders 1 8 148 (0.41)
Rubber Tired Dozers 1 8 367 (0.40)
21 South Coast Air Quality Management District, CEQA Air Quality Handbook, p. 12-3, 1993.

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City of San Dimas 4.1-21 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.1-5: Project Construction Diesel Equipment Inventory Phase Off-Road Equipment Type Amount Daily
Hours
Horsepower[HP]
(Load Factor)
Scrapers 2 8 423 (0.48)
Tractors/Loaders/Backhoes 2 8 84 (0.37)
Building Construction
Cranes 1 7 367 (0.29)
Forklifts 3 8 82 (0.20)
Generator Sets 1 8 14 (0.74)
Tractors/Loaders/Backhoes 3 7 84 (0.37)
Welders 1 8 46 (0.45)
Architectural Coating Air compressors 1 6 37 (0.48)
Paving
Pavers 2 8 81 (0.42)
Paving Equipment 2 8 89 (0.36)
Rollers 2 8 36 (0.38)
Refer to Appendix B, Section 3.0: Construction Detail, for equipment inventory information.

The maximum daily regional construction emissions are provided in Table 4.1-6: Unmitigated Regional Maximum Construction Emissions. CalEEMod assumed the construction period would last approximately 16 years based on the Project details. These impacts would be temporary in nature, lasting only for the construction period, and would not have a long-term impact on the region’s ability to meet State and federal air quality standards. As shown in Table 4.1-6, when modeled without regulatory compliance measures, construction emissions would not exceed SCAQMD daily regional thresholds and impacts would be less than significant.

Table 4.1-6: Unmitigated Regional Maximum Construction Emissions Year
VOC NOx CO SOx PM10 PM2.5
pounds/day
1 3.7 47.0 34.0 0.1 19.4 5.5
2 3.4 31.7 31.2 <0.1 9.3 5.3
3 13.3 46.8 227.0 0.2 47.4 11.7
4 12.8 45.1 212.0 0.2 47.2 11.6
5 12.2 42.3 201.0 0.2 47.2 11.6
6 11.8 39.5 189.0 0.2 47.2 11.6
7 11.3 37.2 178.0 0.2 47.1 11.6
8 9.5 36.0 168.0 0.2 47.1 11.6
9 9.2 33.6 159.0 0.2 47.1 11.5

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City of San Dimas 4.1-22 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.1-6: Unmitigated Regional Maximum Construction Emissions Year
VOC NOx CO SOx PM10 PM2.5
pounds/day
10 8.9 31.4 151.0 0.2 47.1 11.5
11 8.5 30.5 143.0 0.2 47.1 11.5
12 8.3 29.8 137.0 0.2 47.1 11.5
13 71.2 29.5 155.0 0.2 55.3 13.4
14 70.9 29.0 149.0 0.2 55.3 13.4
15 70.7 28.4 145.0 0.2 55.3 13.4
16 63.5 7.1 28.0 <0.1 8.6 2.1
Maximum 71.2 47.0 227.0 0.1 55.3 13.4
SCAQMD threshold 75 100 550 150 150 55
Threshold exceeded? No No No No No No
__________
Source: CalEEMod. Refer to Air Quality Output Sheets in Appendix B.

CO = carbon monoxide; NOx = nitrogen oxides; PM10 = particulate matter less than 10 microns; PM2.5 = particulate matter less than 2.5 microns; VOC = volatile organic compounds; SOx = sulfur oxides.

On-road mobile vehicles, electricity, natural gas, water, landscape equipment, solid waste, and wastewater use associated with the occupancy of development would generate the majority of emissions on-site. The land uses within the DTSP include residential, commercial, retail, restaurant, office, service, open space, and civic uses. The primary source of long-term criteria air pollutant emissions would be from Projectgenerated vehicle trips. As discussed further in Section 4.11: Transportation, it is estimated that projected development in the DTSP Area would generate 691,395 VMT (vehicle miles traveled) in the year 2045 from those traveling within and to the DTSP area. The maximum daily regional operational emissions are provided in Table 4.1-7: Unmitigated Regional Maximum Operational Emissions. As shown in Table 4.1- 7, operational emissions from projected development in the DTSP Area would exceed the SCAQMD daily regional thresholds and area considered significant for this reason. It should be noted that these significance thresholds were developed by SCAQMD for evaluation of individual development projects and, for this reason, the emissions estimated for plans like the DTSP will usually exceed these thresholds.

When taking into account the removal of the existing uses, the net operational emissions would be reduced, however impacts would remain significant.

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City of San Dimas 4.1-23 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.1-7: Unmitigated Regional Maximum Operational Emissions Source
VOC NOx CO SOx PM10 PM2.5
pounds/day
Area 226 55 299 <1 4 4
Energy 1 16 9 <1 1 1
Mobile 154 101 1,290 4 402 103
Total 381 172 1,598 4 407 108
SCAQMD Threshold 55 55 550 150 150 55
Threshold Exceeded? Yes Yes Yes No Yes Yes
__________
Source: CalEEMod. Refer to Air Quality Output Sheets in Appendix B.

Abbreviations: CO = carbon monoxide; NOx = nitrogen oxide; PM10 = particulate matter less than 10 microns; PM2.5 = particulate matter less than 2.5 microns; VOC = volatile organic compound; SCAQMD = South Coast Air Quality Management District; SOX = sulfur oxide.

The DTSP is a planning document to guide development and no specific development projects are proposed at this time. The DTSP would not directly enable or entitle construction or development activities and all future development within the proposed DTSP area will be subject to existing regulations, including adopted air quality standards, and subsequent environmental review under CEQA.

Localized Emissions
Ambient pollutant concentrations standards are forecasted for all criteria pollutants during proposed Project construction. The maximum localized construction and operational emissions are provided in Table

4.1-8: Localized Construction and Operational Emissions. These estimates assume the maximum area that would be disturbed during construction on any given day during the assumed 20-year buildout period for the implementation of the DTSP. Additionally, localized construction emissions include compliance with SCAQMD Rule 403 which is required to reduce impacts related to fugitive dust from the construction site.

The proposed Project would result in a significant construction and operation health impact if concentration impacts would exceed these thresholds and standards.22 As shown in Table 4.1-8, the daily maximum localized construction and emissions would not exceed the SCAQMD daily significance thresholds for NOx, CO, or PM2.5, however, emissions would likely result in an exceedance of daily PM10 emissions. During operation, emissions would not exceed the significance threshold for NOx or CO, however emissions would result in an exceedance of daily PM10 and PM2.5 emissions. Therefore, the daily localized impact of PM10 and PM2.5 emissions would be considered a potentially significant impact. 22 SCAQMD, “Final Localized Significance Methodology.”

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City of San Dimas 4.1-24 Community Development Department Downtown Specific Plan Draft EIR June 2024
As discussed above, the DTSP is a planning document to guide development. Future development facilitated by the DTSP would be subject to the development review process and any potential impacts identified at that time would be addressed through mitigation measures specific to each project.

Table 4.1-8: Localized Construction and Operational Emissions Source
NOx CO PM10 PM2.5
On-Site Emissions (pounds/day)
Construction
Total maximum emissions 36 33 14 3
LST threshold 236 1,566 12 7
Threshold Exceeded? No No Yes No
Operational
Project area/energy emissions 71 308 5 5
LST threshold 236 1,566 3 2
Threshold Exceeded? No No Yes Yes
Source: CalEEMod. Refer to Air Quality Output Sheets in Appendix B Notes: Totals in table may not appear to add exactly due to rounding in the computer model calculations.

CO = carbon monoxide; NOx = nitrogen oxide; PM10 = particulate matter less than 10 microns; PM2.5 = particulate matter less than 2.5 microns.

Valley Fever
Nearby sensitive receptors, as well as workers at the Project site, could be exposed to Valley Fever from fugitive dust generated during construction. There is the potential that cocci spores would be stirred up during excavation, grading, and earth-moving activities, exposing construction workers and nearby sensitive receptors to these spores and thereby to the potential of contracting Valley Fever. However, compliance with SCAQMD Rule 403 during construction, which identifies measures to reduce fugitive dust and is required to be implemented at all construction sites located with the SCAB, and implementation of Mitigation Measure (MM) AQ-2, which would provide personal protective respiratory equipment to construction workers and provide information to all construction personnel and visitors about Valley Fever, the risk of exposure to Valley Fever would be reduced to a less than significant impact. Compliance with the SCAQMD fugitive dust rule and implementation of MM AQ-2, would reduce dust from construction of the Proposed Project, and would not expose nearby sensitive receptors to the Valley Fever fungus.

Accordingly, impacts would be less than significant with mitigation.

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City of San Dimas 4.1-25 Community Development Department Downtown Specific Plan Draft EIR June 2024
Consistency with the 2020-2045 RTP/SCS
The 2020-2045 RTP/SCS provides socioeconomic forecast projections of regional population growth for 14 subregions. The population, housing, and employment forecasts which are adopted by SCAG’s Regional Council, are based on the local plans and policies applicable to the specific area; these are used by SCAG in all phases of implementation and review.

With respect to the first criterion for determining consistency with AQMP growth assumptions, the projections in the AQMP for achieving air quality goals are based on assumptions in SCAG’s 2020 RTP/SCS regarding population, housing, and employment growth. A project is consistent with the AQMP, in part, if it is consistent with the population, housing, and employment growth assumptions that were used in the development of the AQMP. In the case of the 2022 AQMP, SCAG’s 2020 RTP/SCS form the basis of the projections of air pollutant emissions.

According to SCAG, the City of San Dimas had a resident population of 34,200 in 2016 and with growth to 35,000 residents currently projected in 2045.23 Employment is currently projected to increase from 12,100 in 2016 to 12,300 in 2045.24 As discussed in Section 4.9: Population and Housing of this Draft EIR, one of the primary objectives of the proposed DTSP is to change the zoning for the sites identified in the City’s recently adopted 2022 Housing Element for the development of housing needed to meet the City’s Regional Housing Needs Assessment (RHNA) target for the planning period of 2021-2029 identified by SCAG.25 Based on the average household size in San Dimas of 2.91 persons per household, the rezoning within the proposed DTSP Area has the potential to increase the City’s population by approximately 3,631 persons by 2029 if all of these 1,248 units included in the City’s RHNA are built by this date and all of the residents were also new to the City. The resulting increase in population of 1.76 percent (i.e., an increase of 557 people) from the 2021 population. By 2045, the City’s population is projected by SCAG to increase to 35,000, which is an increase of 2.93 percent (i.e., an increase of 997 people) from the 2021 population.

If all 1,248 new units (i.e., 3,631 potential people) are occupied by new residents, the population could increase to 37,634, which is an increase of 3.8 percent (i.e., an increase of 3,631 people) from the 2021 population. This increase in population is higher than the SCAG 2030 population projection of 34,600 and 2045 population projection of 35,000. However, an addition of 1,248 housing units would not substantially induce population growth as the projected growth represents a difference of 9.06 percent (i.e., 3,134 23 Southern California Association of Governments (SCAG), Current context, Demographics and Growth Forecast, accessed July 2023, https://scag.ca.gov/sites/main/files/file-attachments/0903fconnectsocal_demographics-and-growthforecast.pdf?1606001579. 24 Southern California Association of Governments (SCAG), Current context, Demographics and Growth Forecast, accessed July 2023, https://scag.ca.gov/sites/main/files/file-attachments/0903fconnectsocal_demographics-and-growthforecast.pdf?1606001579. 25 City of San Dimas, General Plan, Housing Element,
https://sandimasca.gov/departments/community_development/planning_division/general_plan/housing_element_updat e.php. Accessed July 2023.

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City of San Dimas 4.1-26 Community Development Department Downtown Specific Plan Draft EIR June 2024
people) and 7.53 percent (i.e., 2,634 people) for the years 2030 and 2045, respectively. It is also possible that existing residents currently sharing homes may locate to new units. As the development potential of the proposed DTSP is greater than the current RHNA target of 1,248 units, additional growth in housing units and population could occur between 2029 and 2045 that would further exceed the current SCAG growth forecast for San Dimas. However, all potential growth that may occur as a result of approval of the DTSP would be consistent with the City’s General Plan, which the DTSP is proposed to implement. While the proposed project could potentially increase the population forecast by approximately 9 or greater by 2045, this increase is not considered substantial as the growth would occur over an extended period and the proposed project is intended to help the City implement its Housing Element and meet its RHNA allocation. Future housing development facilitated by the proposed DTSP would occur incrementally over time through 2045, based on market conditions and other constraints. For this reason, the population and housing growth that may be facilitated by the DTSP is considered consistent with the projected growth in the City’s General Plan.
− Does the project include air quality mitigation measures? Future development within the DTSP area would be required to comply with SCAQMD Rule 403, which identifies measures to reduce fugitive dust and is required to be implemented at all construction sites located with the SCAB. Therefore, compliance with SCAQMD Rule 403 that would further reduce fugitive dust emissions was included in CalEEMod as a regulatory compliance measure:
− Control Efficiency of PM10. During construction, methods and techniques should be applied to various operations or equipment when appropriate to reduce estimated emissions related to particulate matter. This includes replacing ground cover in disturbed areas as quickly as possible, yielding an emission reduction efficiency of 15 – 49 percent.26 In addition, SCAQMD Staff recommends that the use of Tier 4 construction equipment of 50 horsepower or greater be required during construction. In the event that Tier 4 construction equipment is unavailable or unfeasible, alternative, and applicable strategies include equipment retrofits with Best Available Control Technology (BACT) devices, but not limited to, a CARB-certified Level 3 Diesel Particulate Filters (DPF).

Level 3 DPFs are capable of achieving at least an 85 percent reduction in particulate matter emissions.27 26 SCAQMD, CEQA Handbook, Tables 11-4, page 11-15, and A11-9-A, page A11-77, accessed July 2023, http://www.aqmd.gov/docs/default-source/ceqa/handbook/localized-significance-thresholds/final-sample-constructionscenario-report.pdf. 27 CARB, Heavy-Duty DECS Installation and Maintenance, accessed July 2023, https://ww2.arb.ca.gov/resources/factsheets/heavy-duty-decs-installation-and-maintenance-frequently-askedquestions#:~:text=Level%203%20%2D%20The%20strategy%20reduces,Example%3A%20Wall%20flow%20filter.

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City of San Dimas 4.1-27 Community Development Department Downtown Specific Plan Draft EIR June 2024
− Construction Equipment Controls. During construction, all off-road construction equipment greater than 50 horsepower shall meet USEPA Tier 3 emission standards with Level 3 DPF to minimize emissions of NOx and particulate matter associated with diesel construction equipment.

As shown in Tables 4.1-7 and 4.1-8, construction and operational emissions would exceed SCAQMD regional and localized thresholds and would potentially result in significant impacts. Mitigation measures MM AQ-1 through MM AQ-4 discussed below, would mitigate the emissions generated by subsequent individual development projects within the DTSP area. MM AQ-1 would require individual developments within the DTSP area to conduct project specific air quality analysis and implement additional mitigation as needed. MM AQ-2 and MM AQ-3 would directly reduce construction emissions including CO, NO2, PM2.5, and PM10 by implementing working training that reviews the SCAQMD Dust Control Plan and requiring the use Tier 4 construction equipment. MM AQ-4 would reduce operational area and energy emissions by using more efficient technology.
b. Would the project result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or State ambient air quality standard?
The cumulative significance methodologies contained in the CEQA Air Quality Handbook, SCAQMD staff has suggested that the emissions-based thresholds be used to determine if a project’s contribution to regional cumulative emissions is cumulatively considerable. Individual projects that exceed SCAQMDrecommended daily thresholds for project-specific impacts would be considered to cause a cumulatively considerable increase in emissions for those pollutants for which the SCAB is in nonattainment.

By applying SCAQMD’s cumulative air quality impact methodology, implementation of the Project would not result in exceedance of regional thresholds during construction (refer to Table 4.1-6). However, the Project would exceed operational thresholds (refer to Table 4.1-7). The proposed Project’s emissions would contribute to existing violations of the criteria pollutants in exceedance (PM10) and are considered potentially significant for this reason. As such, the proposed Project’s cumulative construction and operation related impacts would be potentially significant.

As mentioned previously, the DTSP is a planning document to guide development; it does not propose specific development projects. All future developed would be subject to the existing regulatory environment, including adopted air quality standards, and any impacts identified through site-specific review would be addressed through mitigation measures specific to the impact.

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City of San Dimas 4.1-28 Community Development Department Downtown Specific Plan Draft EIR June 2024
c. Would the project expose sensitive receptors to substantial pollutant concentrations? Implementation of the Proposed Project could expose sensitive receptors to elevated air pollutant concentrations during construction and operation-related activities, specifically carcinogenic or toxic air contaminants as well as elevated air concentrations of CO, NO2, PM10, PM2.5, and SO2. The SCAQMD recommends the evaluation of localized air quality impacts to sensitive receptors in the immediate vicinity of the Project Site because of construction activities. As shown in Table 4.1-8 above, localized construction and operational emissions would likely exceed SCAQMD daily thresholds for PM10 and PM2.5 and would potentially be significant. As discussed above, regulatory compliance measures will be implemented to reduce air quality impacts. Additionally, MM AQ-1 through MM AQ-3 would be required. d. Would the project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
As shown in Table 4.1-7 and Table 4.1-8, the construction and operation of subsequent individual projects within the DTSP area may result in emissions in exceedance of SCAQMD operational thresholds and localized significance thresholds and adverse health impacts from criteria pollutants would be significant.

Mandatory compliance with SCAQMD Rule 1113 would limit the number of VOCs in architectural coatings and solvents and compliance with SCAQMD Rule 403 and 403.1 would reduce particulate emissions during construction activities. However, as shown in Table 4.1-8, future development activity in the DTSP area may generate significant dust (particulate matter) emissions.

SCAQMD does not consider odors generated from the use of construction equipment and activities to be objectionable. For potential odor impacts from the occupancy and operation of subsequent individual development projects, before granting approval of a specific project that would result in the citing of a new source of odor or exposure of a new receptor to existing or planned odor sources, the City would need to consider odor impacts. Since the DTSP is planning document meant to guide development, and no specific development projects are proposed at this time, future projects within the DTSP area would be subject to the development review process and potential impacts identified would be addressed through mitigation measures specific to the impact. Further, the Specific Plan does not permit any land uses associated with strong odor impacts such as wastewater treatment plants, landfills or transfer stations, composting facilities, confined animal facilities, food manufacturing, and chemical plants. For these reasons, potential impacts related to odors would be less than significant.

4.1.4 MITIGATION
As shown in Tables 4.1-7 and 4.1-8, estimated construction and operational emissions from future development in the proposed DTSP area are likely to exceed regional and localized thresholds. For this

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City of San Dimas 4.1-29 Community Development Department Downtown Specific Plan Draft EIR June 2024
reason, the following mitigation measures are proposed to reduce potential emissions to the greatest degree feasible:

Construction Emissions
MM AQ-1: The City shall require future projects subject to discretionary approval that are not found to be exempt from CEQA review to evaluate potential air quality impacts and implement respective mitigation measures to minimize impacts that exceed SCAQMD thresholds.

MM AQ-2: Prior to the issuance of any construction permits, the applicant for an individual development project within the DTSP Area shall prepare and implement a worker training program that describes the potential health hazards associated with Valley Fever, common symptoms, proper safety procedures to minimize health hazards, and notification procedures if suspected work-related symptoms are identified during construction.

Additionally, this training program shall include worker training on the implementation requirements of the SCAQMD approved Dust Control Plan. Copies of the training program shall be provided to the County of Los Angeles Department of Regional Planning. The worker training program shall identify safety measures to be implemented by construction contractors during construction. These measures shall include the following:
• HEPA-filtered, air-conditioned enclosed cabs shall be provided on heavy equipment when available. Workers shall be trained on the proper use of cabs, such as turning on air conditioning prior to using the equipment;
• Communication methods, such as two-way radios, shall be provided for use by workers in enclosed cabs;
• Personal protective equipment (PPE), such as half-mask and/or full-mask respirators equipped with particulate filtration, shall be provided to workers active in dusty work areas upon request;
• Separate, clean eating areas with hand-washing facilities shall be provided for construction workers; and
• Equipment, vehicles, and other items shall be cleaned before they are moved off-site to other work locations.

MM AQ-3: Construction Equipment. The applicant for an individual development project within the DTSP Area shall ensure the following requirements are incorporated into applicable bid documents, purchase orders, and contracts. Contractors shall confirm the ability to supply the compliant construction equipment prior to any ground-disturbing and construction activities:

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City of San Dimas 4.1-30 Community Development Department Downtown Specific Plan Draft EIR June 2024
• Mobile off-road construction equipment (wheeled or tracked) greater than 50 hp used during construction of the project shall meet the U.S. EPA Tier 4 final standards.

In the event of specialized equipment use where Tier 4 equipment is not commercially available at the time of construction, the equipment shall, at a minimum, meet the Tier 3 standards. Zero-emissions construction equipment may be incorporated in lieu of Tier 4 final equipment. A copy of each equipment’s certified tier specification or model year specification shall be available to the City upon request at the time of mobilization of each piece of equipment.
• Mobile off-road construction equipment less than 50 hp used during construction of the individual projects shall be electric or other alternative fuel type. A copy of each unit’s certified tier specification or model year specification shall be available to the City upon request at the time of mobilization of each applicable unit of equipment. • Electric hook-ups to the power grid shall be used instead of temporary diesel- or gasoline-powered generators, whenever feasible during construction of development or projects envisioned in the DTSP. If generators need to be used, the generators shall be non-diesel generators.

Operational Emissions
MM AQ-4: Before occupancy of new structures within the Project Site, the applicant for an individual development project within the DTSP Area must provide to the Director of Community Development of the incorporation of low-emission technology including solar water heaters, air-source heat pump, natural gas, and/or gas boosted solar as deemed appropriate by future project specific analysis.

4.1.5 SIGNIFICANCE AFTER MITIGATION
There are no feasible mitigation measures available to emissions likely to be generated by subsequent individual development projects in the proposed DTSP area to less than significant that would be consistent with the objectives of the DTSP. Reducing growth in the DTSP areas would not necessarily reduce population growth because people could still move to the region or Basin but would reside outside of the DTSP Area. Additionally, as the AQMP is updated to reflect new growth assumptions, the anticipated growth from the DTSP would be accounted for in the next AQMP. Therefore, even with the incorporation of mitigation, impacts would remain significant and unavoidable.

City of San Dimas 4.2-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.2 CULTURAL RESOURCES

4.2.1 INTRODUCTION
This section examines the potential impacts of the Project on cultural resources.

4.4.2 THRESHOLDS OF SIGNIFICANCE
The following thresholds for determining the significance of impacts related to cultural resources are derived from the environmental checklist form contained in Appendix G of the most recent update of the State CEQA Statutes and Guidelines.
a. Would the project cause a substantial adverse change in the significance of a historical resource pursuant to § 1506.5.(b)?
b. Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to § 15064.5.(c)?
c. Would the project disturb any human remains, including those interred outside of formal cemeteries pursuant to § 15064.5.(d)?

4.2.3 ENVIRONMENTAL SETTING
Background
San Dimas is located within the San Gabriel Valley on a large alluvial fan complex that originates from the south flanks of the San Gabriel Mountains. The geology in the vicinity of the specific plan area includes Pre-Mesozoic to Cretaceous plutonic igneous rocks of the Peninsular Ranges Batholith; Paleozoic metamorphic rocks; Late Cenozoic terrestrial, marine, and volcanic deposits; and widespread Quaternary alluvial fan and valley deposits.

Recent archaeological studies within the surrounding area indicate that human occupation of the area dates back almost 10,000 years. San Dimas is thought to sit along the fringes of territories traditionally belonging to the Serrano and Gabrielino Native American cultural groups. Tribal Cultural Resources are discussed in Section 4-14 of this DEIR.

The first Americans arriving in the locality presently known as San Dimas were a band of explorers headed by Jedediah Strong Smith, who camped at a Cienega (marshy area), later called Mud Springs, in 1826. A monument on E. Arrow Highway marks the approximate location. In 1837, two Spanish Dons, Señor Ignacio Palomares and Señor Ricardo Vejar, acquired these vast semi-arid and wilderness pastures. Their immense land grant was christened Rancho San Jose and was a range for vast herds of cattle. An era of droughts and financial reverses resulted in the break-up of the California Rancho. Around this time, a

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City of San Dimas 4.2-2 Community Development Department Downtown Specific Plan Draft EIR June 2024
station of the Banning Stage Line was constructed near the Mud Springs under the purview of Dennis Clancy, the line’s operator. In the 1860s, the Clancy family’s two children were the first American settlers to be born in San Dimas. The site of the former Mud Springs, on Palomares Street, has long been dry.

The first farmers to settle in the area arrived in 1878. They leased large acreage upon which they raised grain until the citrus era dawned, and San Dimas became the “Queen of the citrus belt” in Southern California. With the growth of the Los Angeles metropolitan area, the citrus groves of the early 1900s have, in turn, given way to urbanization, and in 1960 (August 4) the citizens of San Dimas incorporated as a city so that they might chart the course of their development more effectively. Since its incorporation in 1960, the growth of San Dimas has transformed the City from a primarily rural area to an urbanized community containing several industrial, commercial, and residential uses.

Existing Conditions
The Project area consists of portions of the existing downtown of San Dimas and immediately adjacent areas. Most properties within the Project area have been previously developed, with uses including commercial, multi-family residential, and public facilities. The historic commercial downtown district situated along Bonita Avenue (between Cataract and Walnut Avenues) contains a fine-grained urban form with smaller parcels, street-oriented buildings with small setbacks, and buildings that conform to the “Early California Village” architectural theme discussed in the City’s Land Use Element. Outside of this downtown area, the eastern and western portions of the Project area predominantly feature larger parcels on irregular blocks of varying shapes and sizes, with most buildings generally constructed in the middleto late-twentieth century.

The historic downtown, or “Town Core,” contains numerous historic homes, churches, and other buildings.1 The City of San Dimas conducted a historic survey of all pre-1940 buildings in 1991.2 Over 300 structures were identified in this survey as being locally significant, having a state level of significance, or having the potential to be placed on the National Register of Historic Places.

Based in part on the 1991 survey, the City of San Dimas has compiled a list of historically significant structures present within the Project area. This list includes 25 properties that are either locally significant (LS), nationally significant (NS), or are part of the Lower San Dimas Historic District (LSDHD). These buildings are considered notable examples of their architectural style, appear to be in good condition, do 1 LA Conservancy, City of San Dimas, “Historic Structure List,” 1991. Accessed December 23, 2021. https://www.laconservancy.org/sites/default/files/community_documents/San%20Dimas%20Historic%20Structures%20Li st.pdf.
2 City of San Dimas, Planning Division, “Historic Preservation and Sustainability,” accessed December 23, 2021. https://sandimasca.gov/departments/community_development/planning_division/historic_preservation_and_sustainabili ty.php.

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City of San Dimas 4.2-3 Community Development Department Downtown Specific Plan Draft EIR June 2024
not appear to have been significantly modified, and have been listed in the City Register. Therefore, these properties, detailed in Table 4-2.1: Historic Properties in DTSP Study Area below, are considered historical resources for purposes of evaluation of the potential for the proposed Specific Plan to result in significant impacts to historical resources as defined in the CEQA and CEQA Guidelines.

Table 4.2-1: Historic Properties in DTSP Study Area
Address Historic Significance Existing Use
219 E. Arrow Highway Locally Significant Castle Pet Resort (pet grooming and lodging) 121 E. Bonita Ave. Locally Significant Vacant (formerly Police Tax) 145 E. Bonita Ave. Locally Significant Studio K Beauty Suite 246 E. Bonita Ave. Locally Significant San Dimas Chamber of Commerce 358 E. Bonita Ave. Locally Significant Calvary Church of San Dimas 108 W. Bonita Ave. Locally Significant Early Ford Store 114 W. Bonita Ave. Locally Significant Pozzetto's Italian Dining 142 W. Bonita Ave. Locally Significant San Dimas Grain Co. 150 W. Bonita Ave. Locally Significant Agence (hair salon) 151 W. Bonita Ave. Locally Significant Better Home Financial Group 152-68 W. Bonita Ave. Locally Significant
The Perfect 10 Beauty Studios (168), San
Dimas Barber Shop (164), Roady's
Restaurant (160), San Dimas Cake Co. (156),
The Train Tunnel (152)
163 W. Bonita Ave. Locally Significant Quality Instant Printing 175 W. Bonita Ave. Locally Significant ICI World Wide Inc. Corporate Office 201 W. Bonita Ave. Locally Significant
San Dimas Hardware; Existing building is a
complete reconstruction of the former
building
210 W. Bonita Ave. Nationally Significant Pacific Railroad Museum 211-12 W. Bonita Ave. Locally Significant Puzzle Zoo Store; Residential units have been constructed above through MCTA
221 W. Bonita Ave. Locally Significant Sata Lawnmower Shop 225 W. Bonita Ave. Locally Significant San Dimas Wine Shop 233-35 W. Bonita Ave. Locally Significant Second Time Around (233), The Little Back House (235)
115 N. Cataract Ave. Nationally Significant M & E San Dimas LLC; Former San Dimas Packing House
112 N. San Dimas Ave. LSDHD Platform (hair salon)
121 N. San Dimas Ave. LSDHD; Nationally Significant The Walker House

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City of San Dimas 4.2-4 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.2-1: Historic Properties in DTSP Study Area
Address Historic Significance Existing Use
114 E. First St. LSDHD San Dimas Mountain Rescue/LA County Sheriff's Dept.
144 E. First St. LSDHD Existing Single-Family Residence 146 E. First St. LSDHD Existing Single-Family Residence

Source: City of San Dimas

Regulatory Framework
National Historic Preservation Act
The National Historic Preservation Act of 1966 established the National Register of Historic Resources to recognize resources associated with the country’s history and heritage. Structures and features must be at least 50 years old to be considered for listing on the National Register, barring exceptional circumstances. Criteria for listing on the National Register are significance in American history, architecture, archaeology, engineering, and culture as present in districts, sites, buildings, structures, and objects that possess integrity of location, design, setting, materials, workmanship, feeling, and association, and that are any of the following:
a. Associated with events that have made a significant contribution to the broad patterns of our history; b. Associated with the lives of persons significant in our past; c. Embodying the distinctive characteristics of a type, period, or method of construction; represent the work of a master; possess high artistic values; represent a significant and distinguishable entity whose components may lack individual distinction; and
d. Have yielded, or may be likely to yield, information important in prehistory or history (Criterion D is usually reserved for archaeological and paleontological resources).

California Register of Historical Resources
The California Register of Historic Resources (CRHR) includes California State Historical Landmarks; eligible Points of Historical Interest; and resources listed, or formally determined eligible for listing, in the National Register. To be eligible for listing in the California Register, a resource must meet at least one of the following criteria:

1. Be associated with events that have made a significant contribution to the broad patterns of local or regional history or the cultural heritage of California or the United States;

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2. Be associated with the lives of persons important to local, California, or national history;

3. Embodies the distinctive characteristics of a type, period, region, or method of construction or represents the work of a master or possesses high artistic values; or

4. Has yielded, or has the potential to yield, information important to the prehistory or history of the local area, California, or the nation.

In addition, resources must have integrity for the period of significance. The period of significance is the date or span of time within which significant events transpired, or significant individuals made their important contributions. Integrity is the authenticity of a historical resource’s physical identity as evidenced by the survival of characteristics or historic fabric that existed during the resource’s period of significance. Alterations to a resource or changes in its use over time may have historical, cultural, or architectural significance. Simply, resources must retain enough of their historic character or appearance to be recognizable as historical resources and must convey the reasons for their significance.

California Environmental Quality Act
State CEQA Guidelines Section 15064.5 defines a historical resource as: (1) a resource listed in, or determined to be eligible by the State Historical Resources Commission, for listing in the CRHR; (2) a resource included in a local register of historical resources, as defined in Public Resources Code (PRC) Section 5020.1(k) or identified as significant in a historical resource survey meeting the requirements of PRC Section 5024.1(g); and (3) any object, building, structure, site, area, place, record, or manuscript which a lead agency determines to be historically significant or significant in the architectural, engineering, scientific, economic, agricultural, educational, social, political, military, or cultural annals of California by the lead agency, provided the lead agency’s determination is supported by substantial evidence in light of the whole record.

Archaeological resources are defined in CEQA Section 21083.2, which states that a “unique” archaeological resource is an archaeological artifact, object, or site that has a high probability of meeting any of the following criteria:
• Contains information needed to answer important scientific research questions and there is a demonstrable public interest in that information;
• Has a special and particular quality such as being the oldest of its type or the best available example of its type; or
• Is directly associated with a scientifically recognized important prehistoric or historic event or person.

Unique archaeological resources as defined in Section 21083.2 may require reasonable efforts to preserve resources in place (Section 21083.1(a)). If preservation in place is not feasible, mitigation measures shall

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City of San Dimas 4.2-6 Community Development Department Downtown Specific Plan Draft EIR June 2024
be required. Additionally, the State CEQA Guidelines state that if an archaeological resource is neither a unique archaeological nor a historical resource, the effects of the project on those resources shall not be considered a significant effect on the environment (State CEQA Guidelines Section 15064.5(c)(4)).

Section 15064.5(e)(1) and (2) of the CEQA Guidelines provides applicable standards that apply to the accidental discovery of human remains.

City of San Dimas
Following the 1991 historic resources survey, the City prepared design guidelines to help building owners to preserve and rehabilitate buildings identified in the historic resources survey and located within the Town Core area. This resulted in the creation of the San Dimas Town Core Design Guidelines, adopted by the City Council in 1993.

The 1991 historic resources survey also serves as the foundation for the City’s preservation tax incentive program. Any structure identified as a “Historic Resource” by the 1991 survey is eligible for local tax incentives under the Mills Act. The Mills Act is a state law that enables the owner of a structure designated as historically significant by the City to enter an agreement with the City to preserve, maintain, and possibly rehabilitate the structure. Money saved from reduced property taxes under the Mills Act is then available for the owner to maintain and restore the structure. In San Dimas specifically, the Mills Act requires that the owner spend their tax savings on preserving and restoring the historic structure, and under select circumstances, may permit the owner to claim expenses associated with the rehabilitation of historic properties as an additional tax deduction. In order to quality for tax abatement under the Mills Act, a structure:
• Must be a privately owned property which is not exempt from property taxation; • Must be identified as a “Historic Resource” by the City’s 1991 Historic Resources Survey and must not have been altered since the survey in a manner that would change its historical significance, and; • Must include all of their basic structural elements consistent with the Guidelines For The Assessment of Enforceably Restricted Historic Property adopted by the State Board of Equalization in 2005.

The City of San Dimas further maintains standards for how historic preservation must be conducted, following rules developed by the U.S. Department of Interior known as the “Secretary of Interior Standards for Rehabilitation,” listed below. “Rehabilitation” is defined as “the process of returning a property to a state of utility, through repair or alteration, which makes possible an efficient contemporary use while preserving those portions and features of the property which are significant to its historical, architectural, and cultural values.”

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City of San Dimas 4.2-7 Community Development Department Downtown Specific Plan Draft EIR June 2024
The 10 Standards pertain to historic buildings of all materials, construction types, sizes, and occupancy and encompass the exterior and the interior, related landscape features and the building’s site and environment as well as attached, adjacent, or related new construction. The following Standards are to be applied to specific rehabilitation projects in a reasonable manner, taking into consideration economic and technical feasibility:
• A property shall be used for its historic purpose or be placed in a new use that requires minimal change to the defining characteristics of the building and its site and environment. • The historic character of a property shall be retained and preserved. The removal of historical materials or alteration of features and spaces that characterize a property shall be avoided. • Each property shall be recognized as a physical record of its time, place, and use. Changes that create a false sense of historical development, such as adding conjectural features or architectural elements from other buildings, shall not be undertaken.
• Most properties change over time; those changes that have acquired historic significance in their own right shall be retained and preserved.
• Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a property shall be maintained.
• Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials. Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence. • Chemical or physical treatments, such as sandblasting, that cause damage to historical materials shall not be used. The surface cleaning of structures, if appropriate, shall be undertaken using the gentlest means possible.
• Significant archeological resources affected by a project shall be protected and preserved. If such resources must be disturbed, mitigation measures shall be undertaken. • New additions, exterior alterations, or related new construction shall not destroy historic materials that characterize the property. The new work shall be differentiated from the old and shall be compatible with the massing, size, scale, and architectural features to protect the historical integrity of the property and its environment.
• New additions and adjacent or related new construction shall be undertaken in such a manner that if removed in the future, the essential form and integrity of the historic property and its environment would be unimpaired.

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City of San Dimas 4.2-8 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.2.4 IMPACT ANALYSIS
Project Impact
a. Cause a substantial adverse change in the significance of a historical resource pursuant to § 1506.5.(b)?
The proposed Downtown Specific Plan (DTSP) would establish a planning and zoning framework for encouraging transit-oriented development in the greater downtown area while preserving the character of the historic commercial district. The DTSP encourages compact development near the new Metro “A” Line transit station to decrease automobile dependency, reduce both local and regional traffic congestion and related greenhouse gas emissions, and provides additional guidance and includes plans to increase multimodal access to and from the historic Downtown area.

The DTSP land use plan includes guidelines to retain and reflect the historic feel and scale of the buildings along Bonita Avenue in the historic core of the downtown area, generally from Cataract Avenue to San Dimas Avenue, where the historic buildings identified above are located. The Specific Plan strongly encourages the preservation, rehabilitation, and adaptive re-use of historic buildings, and requires new development or redevelopment projects within the Town Core to be architecturally compatible with the existing historic buildings in within the zone.

As described previously, there are 25 recognized historic structures within the planning area that are considered historic resources for the purposes of CEQA. 18 are locally significant, 3 are nationally significant, and 5 are part of the proposed Lower San Dimas Historic District (the Walker House located at 121 N. San Dimas is both nationally significant and part of the proposed Lower San Dimas Historic District).

Several of these structures, particularly along Bonita Avenue, have been modified to accommodate commercial uses.

Section 5.10 Historic Preservation and Adaptive Reuse in the proposed DTSP addresses preservation of individual historic resources and the general historic character of the town core district. Section 5.10.1 of the DTSP addresses adaptive re-use of historic buildings to accommodate new uses, stating that the adapting historic buildings to accommodate new uses, with minimal changes to the structure and maintenance of the historic integrity of a structure, is preferred over the significant alteration or demolition of any historic resource.

In addition, Section 5.10.2 contains the following standards applicable to the alteration and/or adaptive reuse of the structures on the inventory list of the City of San Dimas and as may be added to this list over time:

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City of San Dimas 4.2-9 Community Development Department Downtown Specific Plan Draft EIR June 2024
A. A historic building should be used asit was historically or given a new use thatrequiresminimal change to its distinctive materials, features, spaces and spatial relationships.

B. The historic character of a property should be retained and preserved. The removal of distinctive materials or alteration of features, spaces, and spatial relationships that characterize a property shall be avoided.

C. Each property shall be recognized as a physical record of its time, place and use. Changes that create a false sense of historical development, such as adding conjectural features or elements from other historic properties, shall not be undertaken. Changes to a property that have acquired historic significance in their own right shall be retained and preserved.

D. Distinctive materials, features, finishes, and construction techniques or examples of craftsmanship that characterize a property shall be preserved.

E. Deteriorated historic features shall be repaired rather than replaced. Where the severity of the deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture and where possible, materials.

F. Replacement of missing features shall be substantiated by documentary and physical evidence.

G. Chemical or physical treatments, if appropriate, shall be undertaken using the gentlest means possible. Treatments that cause damage to historic materials shall not be used.

H. Archaeological resources shall be protected and preserved in place. If such resources must be disturbed, mitigation measures shall be undertaken.

Section 5.10.3 of the DTSP includes guidelines for development of sites within the Town Core area and for properties adjacent to identified historic resources. These guidelines call for new development within the Town Core to be particularly sensitive to the existing, established, historic building form and block patterns. In addition, new development located adjacent to properties on the City’s historic inventory list is to be designed with appropriate transitions, massing, and scale to avoid overwhelming and dominating adjacent historic buildings.

As a plan proposed to implement the City’s General Plan, the DTSP would not result in any specific individual development projects that could directly or indirectly impact historic resources considering the proposed policies, design guidelines and development standards. Since the date of the 1991 historic resource survey, other buildings and structures in the downtown area may have attained an age of 45 years or greater and may qualify as historic resources. As discussed above, the policies, guidelines, and standards in the proposed DTSP will apply to structures on the current inventory list of the City of San Dimas and resources that may be added to this list over time. Furthermore, all individual historic resources are protected under CEQA. Mitigation Measures MM CUL-1 and MM CUL-2 are proposed to ensure that development that may be facilitated by the DTSP avoids impacts to historic resources to the fullest extent

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City of San Dimas 4.2-10 Community Development Department Downtown Specific Plan Draft EIR June 2024
feasible. Adoption and implementation of these measures will mitigate potential impacts to historic resources in the DTSP area to less than significant.
b. Cause a substantial adverse change in the significance of an archaeological resource pursuant to § 15064.5.(c)?
There are no known archaeological sites reported within the Project area and the portions of the Project area that have been previously disturbed are unlikely to yield intact archaeological deposits. c. Disturb any human remains, including those interred outside of formal cemeteries pursuant to § 15064.5.(d)?
There are no known human burials within the Project area. Construction of the future development enabled by the Project could uncover unknown subsurface resources. In the event of an accidental discovery or recognition of any suspected human remains, California State Health and Safety Code Section 7050.5 dictates that no further excavation or disturbance of the site may occur until the County Coroner determines that no investigation of the cause of death is required. If human remains are encountered and determined to be Native American in origin, the County Coroner shall contact the Native American Heritage Commission by telephone within 24 hours.

Cumulative Impacts
Potential impacts of the Project on cultural resources combined with the impacts of other reasonably foreseeable projects could contribute to a cumulative loss of cultural resources. Each development proposal within the Project and each related project proposed in the surrounding area would be required to comply with the requirements of CEQA, including regulatory requirements and the mitigation measures discussed below. These measures would ensure that the future development within the Project would not result in significant impacts on cultural resources and would likewise ensure that the Project would not have a considerable contribution to significant cumulative impacts.

4.2.5 MITIGATION
To address the potential impacts on historic resources, the following mitigation shall be incorporated into the Project:

MM-CUL-1 Historical Resources Evaluation. During review of applications for individual development projects in the DTSP area, the City shall confirm the presence of historical resources with the potential to be impacted by the proposed project. If the property on which the project or development is proposed is not currently designated but contains built environment features over 45 years of age, a historical resources evaluation shall be prepared by an architectural historian or historian who meets the Secretary of the Interior’s (SOI)

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City of San Dimas 4.2-11 Community Development Department Downtown Specific Plan Draft EIR June 2024
Professional Qualification Standards (PQS) in architectural history or history (36 Code of Federal Regulations Part 61). The qualified architectural historian or historian shall conduct an intensive-level survey and perform the historical evaluation in accordance with the guidelines and best practices promulgated by the California Office of Historic Preservation (OHP). Properties shall be evaluated within their historic context and documented in a report meeting the California OHP guidelines. All evaluated properties shall be documented on California Department of Parks and Recreation Series 523 Forms.

The report with attached DPR forms shall be submitted to the City for review and concurrence.

MM-CUL-2 Prior to obtaining a building permit for any structure that would modify a structure included on the City’s list of historic resources, a Historical Resource Documentation Report shall be prepared by an architectural historian or historian who meets the Secretary of the Interior’s (SOI) Professional Qualification Standards (PQS) in architectural history or history (36 Code of Federal Regulations Part 61) that demonstrates that all modifications will be designed and implemented in compliance with the Secretary of the Interior’s Standards for Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring, and Reconstructing Historic Buildings and/or the State Historical Building Code, as appropriate.

With regulatory compliance and implementation of the mitigation measures above, no significant unavoidable adverse impacts relating to cultural resources would occur.

City of San Dimas 4.3-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.3 ENERGY

4.3.1 THRESHOLDS OF SIGNIFICANCE
The following thresholds for determining the significance of impacts related to energy resources are derived from the environmental checklist form contained in Appendix G of the most recent update of the State CEQA Statutes and Guidelines.

Except as provided in Public Resources Code Section 21099, would the project:
a. Result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? b. Conflict with or obstruct a state or local plan for renewable energy or energy efficiency?

4.3.2 ENVIRONMENTAL SETTING
Existing Conditions
The primary forms of energy consumed in San Dimas are electricity, natural gas and petroleum used for vehicles. San Dimas is serviced by Southern California Edison (SCE) for electricity and by Southern California Gas Company (SoCalGas) for natural gas.1 Petroleum fuels are generally purchased individually at retail locations.

Regulatory Framework
Senate Bill 2 (1X)
SB 2 (1X) was passed in April 2011 and became effective December 10, 2011. SB 2 (1X) requires utilities to procure eligible renewable energy resources of 33 percent by 2020, including the following interim targets:
• Maintain at least an average of 20 percent renewables between 2011 and 2013. • Achieve 25 percent renewables by 2016.
• Achieve 27 percent renewables by 2017.
• Achieve 29 percent renewables by 2018.
• Achieve 31 percent renewables by 2019.
• Achieve 33 percent renewables by 2020.
1 City of San Dimas. “Utilities & Franchises.” Accessed May 2024. https://sandimasca.gov/departments/administration/utilities___franchises.php.

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Senate Bill 350
SB 350, which was passed in September 2015 and became effective October 7, 2015, requires utilities to procure eligible renewable energy resources of 50 percent by 2030, including the following interim targets:
• Achieve 40 percent renewables by 2024.
• Achieve 45 percent renewables by 2027.
• Achieve 50 percent renewables by 2030 and maintain this level in all subsequent years.

SB 350 also requires the State to double statewide energy efficiency savings in electricity and natural gas uses by 2030. The law requires publicly owned utilities to establish annual targets for energy efficiency savings and demand reductions consistent with the Statewide goal. The Public Utilities Commission also must approve programs and investments by electrical corporations in transportation electrification, including electric vehicle charging infrastructure.

California’s Renewable Portfolio Standard (Senate Bill 100) SB 100, signed September 10, 2018, is the 100 Percent Clean Energy Act of 2018. SB 100 updates the goals of California’s RPS and SB 350, as discussed above, to the following: achieve 50 percent renewable resources target by December 31, 2026, and achieve a 60-percent target by December 31, 2030. SB 100 also requires that eligible renewable energy resources and zero-carbon resources supply 100 percent of retail sales of electricity of California end-use customers and 100 percent of electricity procured to serve all state agencies by December 31, 2045.

California Building Standards (Title 24)
The California Building Energy Efficiency Standards for Residential and Nonresidential Buildings (California Code of Regulations, Title 24, Part 6) were adopted to ensure that building construction and system design and installation achieve energy efficiency and preserve indoor and outdoor environmental quality. The current California Building Energy Efficiency Standards (Title 24 standards) are the 2022 Title 24 standards, which became effective on January 1, 2023. The 2022Title 24 standards continue to improve upon the 2019Title 24 standards for new construction of, and additions and alterations to, residential and nonresidential buildings which include efficiency improvements to the residential standards for attics, walls, water heating, and lighting, and efficiency improvements to the nonresidential standards include alignment with the American Society of Heating and Air-Conditioning Engineers (ASHRAE) 90.1-20173 national standards.

The California Green Building Standards Code (California Code of Regulations, Title 24, Part 11), commonly referred to as the CALGreen Code, initially went into effect on January 1, 2011, and is updated every three

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years. The 2022 CALGreen Code includes mandatory measures for residential and nonresidential development related to site development; energy efficiency; water efficiency and conservation; material conservation and resource efficiency; and environmental quality. For new multifamily dwelling units, the residential mandatory measures were revised to provide additional EV charging requirements, including quantity, location, size, single EV space, multiple EV spaces, and identification.

Sustainable Communities Strategy
The Sustainable Communities and Climate Protection Act of 2008, or SB 375, coordinates land use planning, regional transportation plans, and funding priorities to help California meet its GHG reduction goals. SB 375 specifically required each Metropolitan Planning Organization (MPO) to prepare a “Sustainable Communities Strategy” (SCS) as part of its Regional Transportation Plan (RTP). The Specific Plan Area is located within the planning jurisdiction of Southern California Association of Governments (SCAG). SCAG’s first Sustainable Communities Strategy (SCS) was the 2012-2035 Regional Transportation Plan/Sustainable Communities Strategy (2012-2035 RTP/SCS), which was adopted by SCAG in April 2012.

SCAG has since adopted the 2016-2040 RTP/SCS and the 2020-2045 RTP/SCS, its current iteration. The goals and policies of the SCS are intended to reduce VMT and result in corresponding decreases in transportation-related fuel consumption by focusing on transportation and land use planning that include building infill projects, locating residents closer to where they work and play, and designing communities so there is access to high quality transit service.

4.3.3 IMPACT ANALYSIS
a. Result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? b. Conflict with or obstruct a state or local plan for renewable energy or energy efficiency? The Project creates a planning framework for future development. As such, the Project would not have direct energy impacts. However, the Project facilitates future development that would consume energy during construction and operation.

As indicated above in presenting the regulatory framework, the energy suppliers are required to achieve greater energy efficiency and conservation over time and no conflict between the Project and these plans has been identified. In addition, future development within the Project would be required to meet the building standards if the Project as well as the requirements of the California Building Code related to water and energy conservation, including Energy Efficiency Standards and Green Building Standards, that are applicable at the time of construction. As such, energy use by future projects would be more efficient.

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The Project also creates a framework for development that would be mixed-use and transit-oriented. A Transit Oriented Development is a “moderate to higher-density development, located within an easy walk of a major transit stop, generally with a mix of residential, employment and shopping opportunities designed for pedestrians without excluding the auto.”2 As such, the Project would support a reduction in vehicle miles traveled, which would reduce the consumption of transportation fuel energy.

Based on the above, the Project would neither result in wasteful, inefficient or unnecessary consumption of energy nor conflict with state or local plan for renewable energy or energy efficiency.

Cumulative Impact
Energy consumption is regional in nature as the energy providers such as SCE and SoCalGasforecast energy needs based on regional growth forecasts. The Project accommodates expected growth in San Dimas in a framework that would reduce average energy consumption through the design of a walkable, transitoriented downtown with new Building Code-compliant structures. As such, the Project would not result in a considerable contribution to regional cumulative energy impacts.

4.3.4 MITIGATION
As impacts would be less than significant, no mitigation is necessary. 2 California Department of Transportation. Statewide Transit Oriented Development Study – Factors for Success in California. 2002.

City of San Dimas 4.4-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.4 GEOLOGY AND SOILS

4.4.1 INTRODUCTION
This section examines the potential impacts of the Project on paleontological resources. The Initial Study prepared for the Project determined that impacts to other geology and soil thresholds would be less than significant and therefore did not need to be evaluated in this EIR.

4.4.2 THRESHOLDS OF SIGNIFICANCE
The following thresholds for determining the significance of impacts related to geology is derived from the environmental checklist form contained in Appendix G of the most recent update of the State CEQA Statutes and Guidelines:
a. Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?

4.4.2 ENVIRONMENTAL SETTING
Existing Conditions
The Project site is predominantly developed urban land that has been disturbed in the past. Most properties within the Study Area have been previously developed, with uses including commercial, multifamily, and public facilities. No unique paleontological resource or site or unique geologic feature have been recorded as unearthed within the project boundary.

Paleontological resources are the fossilized remains of organisms that have lived in a region in the geologic past and whose remains are found in the accompanying geologic strata. Paleontological records searches conducted for other projects with the City have indicated that fossils have been found in the area of Puddingstone Lake and Bonelli Regional Park.1 The closest recorded find was at Puddingstone Dam, within a mile of the Project site.

Regulatory Framework
City of San Dimas General Plan
The Conservation Element of the City’s General Plan states that “Paleontological sites yield specimens of fossil flora and fauna which are a resource for scientific knowledge.” It continues to note that there are fossil bearing rocks within the City specifically shale and siltstone strata in the Via Verde and around Bonelli 1 UltraSystems Environmental Inc. Initial Study and Mitigated Negative Declaration (IS/MND) for Allen-Cataract Warehouse Project, State Clearinghouse Number 2023030132. January 2023. Accessed May 2024. https://ceqanet.opr.ca.gov/2023030132.

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Park. The General Plan concludes that “Future Development should avoid needless destruction of the remaining paleontological sites.”2
Paleontological Resources Preservation Act
The Paleontological Resources Preservation Act (PRPA) of 2009 calls for uniform policies and standards that apply to fossils on all federal public lands. The Project does not contain Federal Public Land, and as such the PRPA does not apply. However, the Society for Vertebrate Paleontology (SVP) has established standard guidelines3 that satisfy the stipulations of the PRPA and these guidelines provide a definition of unique paleontological resources that is useful in the evaluation of the Project not within Federal Public Land.

Based on the significance definitions of the SVP4
, all identifiable vertebrate fossils are considered to have significant scientific value. Vertebrate fossils are relatively uncommon, and only rarely will a site yield a statistically significant number of specimens of the same genus. Therefore, every vertebrate fossil found has the potential to provide significant new information on the taxon it represents, its paleoenvironment, and/or its distribution. Furthermore, all geologic units in which vertebrate fossils have previously been found are considered to have high sensitivity. Identifiable plant and invertebrate fossils are considered significant if found in association with vertebrate fossils or if defined as significant by project paleontologists, specialists, or local government agencies.

4.4.3 IMPACT ANALYSIS
a. Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? No unique paleontological resources or unique geologic feature are known to be present within the Project Site. While unique paleontological resources have been found within one mile of the Project site, these finds are within an area identified in the General Plan as a different geologic stratum.

Nonetheless, if future development enabled by the Project involves excavation of previously undisturbed soils, while unlikely, it is possible that unknown resources could be inadvertently unearthed. During this process it is possible, though unlikely, that paleontological resources may be unearthed. As such, an additional mitigation measure has been detailed below in the case that such an event were to occur. 2 City of San Dimas. General Plan Conservation Element, Page VI-16. 3 Society of Vertebrate Paleontology, Standard Procedures for the Assessment and Mitigation of Adverse Impacts to Paleontological Resources, 2010, http://vertpaleo.org/Membership/Member-Ethics/SVP_Impact_Mitigation_ GUIDELINES.aspx.
4 Society of Vertebrate Paleontology, Assessment and Mitigation of Adverse Impacts to Nonrenewable Palaeontologic Resources: Standard Guidelines, Society of Vertebrate Paleontology News Bulletin 163:22-27, 1995.

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Cumulative Impact
Cumulative impacts could occur through widespread adverse changes in the significance of paleontological resources. Implementation of the mitigation measure identified below would ensure that the Project would not have a considerable contribution to cumulative impacts on paleontological resources.

4.4.4 MITIGATION
The following mitigation measure shall be incorporated into the Project to reduce the potential for impacts from inadvertent discovery of paleontological resources:

MM-GEO-1: Unanticipated Discovery of Paleontological Resources. In the event an unanticipated fossil discovery is made during project development, work in the immediate vicinity of the find shall be stopped, and a qualified professional paleontologist shall be retained to evaluate the discovery, determine its significance, and identify if mitigation or treatment is warranted. Significant paleontological resources found during construction monitoring shall be prepared, identified, analyzed, and permanently curated in an approved regional museum repository. Work around the discovery shall only resume once the find is properly documented and authorization is given to resume construction work.

With implementation of the above mitigation measure, no significant unavoidable adverse impacts relating to paleontological would result.

City of San Dimas 4.5-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.5 GREENHOUSE GAS EMISSIONS

4.5.1 THRESHOLDS OF SIGNIFICANCE
Appendix G of the State CEQA Statutes and Guidelines includes the following greenhouse gas thresholds as part of the environmental checklist:

Would the project:
a. Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment?
b. Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases?
In addition, Section 15064.4 of the CEQA Guidelines provides guidance for lead agencies to determine the significance of greenhouse gas (GHG) impacts. Specifically, a lead agency has the discretion to determine, in the context of a particular project, whether to use a model or methodology to quantify GHG emissions or to rely on a qualitative analysis or performance-based standards. Furthermore, a lead agency should consider the extent to which the project may increase or reduce GHG emissions as compared to the existing environmental setting and the extent to which the project complies with regulations or requirements adopted to implement a statewide, regional, or local plan for the reduction or mitigation of GHG emissions.

Neither the City nor the State have adopted specific applicable quantitative thresholds for Greenhouse Gases (GHG) emissions. In the context of CEQA, “GHG impacts are exclusively cumulative impacts; there are no noncumulative GHG emission impacts from a climate change perspective.”1 Per CEQA Guidelines, a project’s incremental contribution to a cumulative impact can be found not cumulatively considerable if the project would comply with an approved plan or mitigation program that provides specific requirements that would avoid or substantially lessen the cumulative problem within the geographic area of the project.2 In 2020 the Southern California Association of Governments (SCAG) adopted Connect SoCal as the 2020–2045 Regional Transportation Plan and Sustainable Communities Strategy to provide policies and growth strategies designed to achieve the State’s GHG reduction goals for the region. As such, 1 CAPCOA, CEQA & Climate Change (January 2008), p. 35. See also SCAQMD, CEQA Guide (February 2016), p. 6-1 [“…from the standpoint of CEQA, GHG impacts to global climate change are inherently cumulative…”]; SJVAPCD, Guidance for Valley Land-use Agencies in Addressing GHG Emission Impacts for New Projects under CEQA (December 2009), p. 4 [“…effects of project specific GHG emissions are cumulative…”]; California Natural Resources Agency, Final Statement of Reasons for Regulatory Action, December 2009.
2 CEQA Guidelines Section 15064(h)(3).

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a finding of less than significant impact on GHG emissions can be made if the Project complies with the policies and strategies of Connect SoCal.

4.5.2 ENVIRONMENTAL SETTING
Sources of Greenhouse Gas Emissions
GHGs are a group of emissions that include CO2, methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorinated chemicals (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). Other GHGs emissions are less abundant than CO2 so are frequently expressed in the equivalent mass of CO2; denoted as CO2e.

GHGs are the result of both natural and anthropogenic activities. With respect to anthropogenic activities, motor vehicle travel, air travel, consumption of fossil fuels for power generation, industrial processes, heating and cooling, landfills, agriculture, and wildfire are the primary sources of GHG emissions.

Additionally, land use decisions and future development projects pursuant to implementation of a general plan can affect the generation of GHG emissions from multiple sectors, resulting in direct or indirect GHG emissions. For example, electricity consumed in the lighting and heating of buildings is an indirect source of GHG emissions because it requires electricity from power plants, which emit GHG directly into the atmosphere. Conversely, tailpipe emissions from the use of vehicles generate direct GHG emissions.

Greenhouse Effect
GHGs are global pollutants that have long atmospheric lifetimes (one year to several thousand years).

GHGs persist in the atmosphere for a long enough time to be dispersed around the globe. GHGs play a critical role in determining the Earth’s surface temperature, as these gases absorb solar radiation. Solar radiation enters the Earth’s atmosphere from space. A portion of the radiation is absorbed by the Earth’s surface, and a smaller portion of this radiation is reflected into space. The radiation absorbed by the Earth is reradiated as lower-frequency infrared radiation, which is then selectively absorbed by GHGs in the Earth’s atmosphere. As a result, the greater the amount of GHGs in the atmosphere, the greater the amount of infrared radiation trapped, resulting in a warming of the atmosphere. This phenomenon is commonly referred to as the “greenhouse effect.” Scientists have speculated that increased GHG emissions from human activity (anthropogenic) could lead to a less habitable climate. Anthropogenic GHG emissions leading to atmospheric levels more than natural ambient concentrations are responsible for intensifying the greenhouse effect and have led to a trend of unnatural warming of the Earth’s atmosphere and oceans, with corresponding effects on global air and water circulation patterns. According to the California Air Resources Board (CARB) some of the potential California-specific impacts of this climate change may include loss of snowpack, sea level rise, more extreme heat days per year, more high ozone days, more large forest fires, and more drought years.

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Regulatory Framework
Executive Order S-3-05
Executive Order S-3-05, signed by Governor Arnold Schwarzenegger and issued in June 2005, proclaimed that California is vulnerable to the impacts of climate change.3 It declared that increased temperatures could reduce the Sierra snowpack, further exacerbate California’s air quality problems, and potentially cause a rise in sea levels. To combat those concerns, the Executive Order established targets of reducing GHG emissions to 2000 levels by 2010; to 1990 levels by 2020; and to 80 percent below 1990 levels by 2050. However, in adopting the California Global Warming Solutions Act of 2006, also known as Assembly Bill (AB) 32 (Pavley), discussed below, the Legislature did not adopt the 2050 horizon-year goal from Executive Order No. S-3-05 and, in the 2006 legislative session, rejected legislation to enact the Executive Order’s 2050 goal.

Executive Order S-01-07
Executive Order S-1-07, the Low Carbon Fuel Standard (issued on January 18, 2007), requires a reduction of at least 10 percent in the carbon intensity of California’s transportation fuels by 2020.4 Regulatory proceedings and implementation of the Low Carbon Fuel Standard have been directed to CARB. The Low Carbon Fuel Standard has been identified by CARB as a discrete early action item in the adopted Climate Change Scoping Plan (discussed below). CARB expects the Low Carbon Fuel Standard to achieve the minimum 10 percent reduction goal; however, many of the early action items outlined in the Climate Change Scoping Plan work in tandem with one another. Other specific emission reduction measures included are the Million Solar Roofs Program5 and AB 1493 (Pavley I), Vehicle Emissions: Greenhouse Gases, which establishes motor vehicle GHG emissions standards.6 To avoid the potential for doublecounting emission reductions associated with AB 1493, the Climate Change Scoping Plan has modified the aggregate reduction expected from the Low Carbon Fuel Standard to 9.1 percent. In accordance with the Climate Change Scoping Plan, this analysis incorporates the modified reduction potential for the Low Carbon Fuel Standard. CARB released a draft version of the Low Carbon Fuel Standard in October 2008.

The final regulation was approved by the Office of Administrative Law and filed with the Secretary of State on January 12, 2010; the Low Carbon Fuel Standard became effective on the same day. 3 National Resources Conservation Service, “Emerging Issues Committee Members,” https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_008701.pdf. 4 Office of the Governor, Executive Order S-01-07 (January 18, 2007), https://www.arb.ca.gov/fuels/lcfs/eos0107.pdf. 5 US Department of Energy, “Laying the Foundation for Solar America: The Million Solar Roofs Initiative,” October 2016, https://www.nrel.gov/docs/fy07osti/40483.pdf.
6 The standards enacted in Pavley I are the first GHG standards in the nation for passenger vehicles and took effect for model years starting in 2009 and going through 2016. Pavley I could potentially result in 27.7 million metric tons CO2e reduction in 2020. Pavley II will cover model years 2017 to 2025 and potentially result in an additional reduction of 4.1 million metric tons CO2e.

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Executive Order B-30-15 and B-55-18
Executive Order B-30-15, signed by Governor Edmund Gerald “Jerry” Brown and issued on April 29, 2015, established a new Statewide policy goal to reduce GHG emissions to 40 percent below their 1990 levels by 2030. Reducing GHG emissions by 40 percent below 1990 levels in 2030, and by 80 percent below 1990 levels by 2050 (consistent with Executive Order S-3-05), aligns with scientifically established levels needed to limit global warming to less than 2 degrees Celsius.7 EO B-30-15 also directed all State agencies with jurisdiction over GHG-emitting sources to implement measures designed to achieve the new interim 2030 target, as well as the preexisting, long-term 2050 target identified in EO S-3-05 (see discussion above).

Additionally, EO S-3-05 directed CARB to update its Scoping Plan (see discussion below) to address the 2030 target. EO B-55-18, issued by Governor Brown on September 10, 2018, directs the State to achieve carbon neutrality no later than 2045 and achieve and maintain net negative emissions thereafter.

Assembly Bill 32
AB 32, the Global Warming Solutions Act of 2006, required a sharp reduction of GHG emissions to 1990 levels by 2020. To achieve these goals, AB 32 mandates that CARB establish a quantified emissions cap and institute a schedule to meet the cap; implement regulations to reduce Statewide GHG emissions from stationary sources consistent with the California Climate Action Team strategies; and develop tracking, reporting, and enforcement mechanisms to ensure that reductions are achieved. To reach the reduction targets, AB 32 requires CARB to adopt—in an open, public process—rules and regulations that achieve the maximum technologically feasible and cost-effective GHG reductions.

The California Climate Action Team stated that “smart land use” is an umbrella term for strategies that integrate transportation and land-use decisions.8 Such strategies generally encourage jobs/housing proximity, promote transit-oriented development (TOD), and encourage high-density residential/commercial development along transit corridors. These strategies develop more efficient landuse patterns within each jurisdiction or region to match population increases, workforce, and socioeconomic needs for the full spectrum of the population. “Intelligent transportation systems” is the application of advanced technology systems and management strategies to improve operational efficiency of transportation systems and the movement of people, goods, and service.9 7 Office of the Governor, “Governor Brown Established Most Ambitious Greenhouse Gas Reduction Target in North America” (April 29, 2015), https://www.gov.ca.gov/2015/04/29/news18938/. 8 California Energy Commission, “The Role of Land Use in Meeting California’s Energy and Climate Change Goals” (June 2007), http://www.energy.ca.gov/2007publications/CEC-600-2007-008/CEC-600-2007-008-SD.PDF. 9 California Environmental Protection Agency, Climate Action Team Report to Governor Schwarzenegger and the Legislature (March 2006), 58.

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City of San Dimas 4.5-5 Community Development Department Downtown Specific Plan Draft EIR June 2024
AB 197: Statewide GHG Emissions Limit
On September 8, 2016, Governor Brown signed AB 197, which requires CARB to approve a Statewide GHG emissions limit equivalent to the Statewide GHG emission level in 1990 to be achieved by 2020.10 AB 197 requires the CARB to prepare and approve a scoping plan for achieving the maximum technologically feasible and cost-effective reductions in GHG emissions. The bill became effective on January 1, 2017.

Senate Bill 375
SB 375, signed into law in September 2008, aligns regional transportation planning efforts, regional GHG reduction targets, and land use and housing allocations.11 The act requires metropolitan planning organizations (MPOs) to adopt a Sustainable Communities Strategy (SCS) or Alternative Planning Strategy (APS) that prescribes land use allocation in that MPO’s regional transportation plan (RTP).

CARB Scoping Plan
As required by AB 32, CARB approved a Climate Change Scoping Plan in 2008 and has adopted updated plans in 2014, 2017, and 2022. The Scoping Plans have included a range of GHG reduction actions at the state level and recommendations at the local level.

SCAG 2020-2045 Regional Transportation Plan/Sustainable Communities Strategy SCAG is the metropolitan planning organization (MPO) for Los Angeles, Orange, Ventura, Riverside, San Bernardino, and Imperial Counties and serves as a forum for the discussion of regional issues related to transportation, the economy, community development, and the environment. To comply with SB 375, SCAG has prepared and adopted the 2020–2045 RTP/SCS,12 which includes a Sustainable Communities Strategy that addresses regional development and growth forecasts. The SCAG 2020–2045 RTP/SCS is a long-range visioning plan that balances future mobility and housing needs with economic, environmental, and public health goals, with a specific goal of achieving an 8 percent reduction in passenger vehicle GHG emissions on a per capita basis by 2020, a 19 percent reduction by 2035, and a 21 percent reduction by 2040 as compared to the 2005 levels.
10 California Legislative Information, Assembly Bill No. 197 (September 8, 2016), https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201520160AB197. 11 California Legislative Information, Senate Bill No. 375 (September 30, 2008), https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=200720080SB375. 12 Southern California Association of Governments (SCAG), Connect SoCal: 2020-2045 Regional Transportation Plan/Sustainable Communities Strategies Draft, “Chapter 1,” https://www.connectsocal.org/Pages/Connect-SoCal-DraftPlan.aspx, Accessed on July 10, 2020.

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4.5.3 IMPACT ANALYSIS
a. Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment?
b. Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases?
Characteristics of the Project
The Project would create a new development framework for Downtown San Dimas. The Specific Plan aims to enhance the existing character of the downtown area and provide opportunities for new housing, retail, restaurant, cultural, and civic uses that would vitalize the commercial center of the City. The Project would establish the general type, parameters, and character of development to foster an integrated downtown and transit-oriented district around the new Metro station. By allowing for a variety of housing types, the Project would provide increased housing opportunities located within a walkable mixed-use area that is also served by regional transit. The Project would promote alternative transportation methods to link the community to the new rail station. The Project would also foster safe, accessible pedestrian routes within and around downtown, and would also support growth that is sustainable for the City’s public infrastructure and public services.

Consistency with Connect SoCal
As stated previously, a finding of less than significant impact on GHG emissions can be made if the Project complies with the policies and strategies of Connect SoCal. Connect SoCal includes strategies that identify how growth within the region can be accommodated to achieve the targeted GHG reductions. The core vision of Connect SoCal is to build upon and expand land use and transportation strategies established over several planning cycles to increase mobility options and achieve a more sustainable growth pattern.

Connect SoCal focuses on transportation infrastructure and existing job centers to determine where future growth of employment and households should occur. Priority Growth Areas have been identified in the region where growth is forecasted to occur due to proximity to existing and planned transit, existing job centers, existing and planned infrastructure to support more walkability and use of alternative transportation modes, and in areas identified for jurisdictional expansion (i.e. spheres of influence). These Priority Growth Areas include Transit Priority Areas, High Quality Transit Areas, Job Centers, Livable Corridors, and Neighborhood Mobility Areas. Collectively, these Priority Growth Areas are anticipated to contain 95 percent of the growth in the region through the horizon year of 2045. The following tables present the consistency of the Project with the goals, strategies, and tools of Connect SoCal.

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Table 4.5-1: Consistency with Connect SoCal Goals
Goals Consistency Analysis
Goal 1: Encourage regional
economic prosperity and global
competitiveness
Supportive. This goal is directed towards regional economic status. The Project would facilitate the continued economic vitality of downtown San Dimas that would support the overall prosperity of the region.

Goal 2: Improve mobility,
accessibility, reliability, and travel
safety for people and goods.

Supportive. The Project would support a safe, attractive, and accessible mobility network for multiple methods of travel within the downtown area.

Goal 3: Enhance the preservation,
security, and resilience of the
regional transportation system.

Supportive. The Project would support the use of the Metro transit system by promoting development in the downtown that is transit oriented in nature.

Goal 4: Increase person and goods
movement and travel choices within
the transportation system.

Supportive. The Project would support this goal by providing multiple choices of transportation mode within the downtown area.

Goal 5: Reduce greenhouse gas
emissions and improve air quality.

Supportive. The Project would create a framework for development that would be transit- oriented and pedestrian-friendly in an area classified by SCAG as a high-quality transit area. As such, it is expected to reduce vehicle miles travelled as compared to other development frameworks.

Goal 6: Support healthy and
equitable communities.

Supportive. The Project would support the development of a range of housing types as well as commercial uses and public facilities that would support the community.

Goal 7: Adapt to a changing climate
and support an integrated regional
development pattern and
transportation network.

Supportive. The Project would create a framework for the long-term vitality of the downtown that is integrated into the regional transit network.

Goal 8: Leverage new transportation
technologies and data-driven
solutions that result in more efficient
travel.

Supportive. The Project leverages Metro’s investment in rail transit as well as data driven-planning strategies intended to create a more travel-efficient downtown.

Goal 9: Encourage development of
diverse housing types in areas that
are supported by multiple
transportation options.

Supportive. The Project would provide for a range of residential unit types in an area in the City that offers multiple transportation options.

Goal 10: Promote conservation of
natural and agricultural lands and
restoration of habitats.

Supportive. The Project would support infill development that would accommodate development demand and thereby reduce development pressure on natural and agricultural lands.

Source: SCAG, Connect SoCal, 2020–2045 RTP/SCS, September 2020.

Table 4.5-2: Consistency with Connect SoCal Principles
Principles Consistency Analysis
Principle 1. Base transportation investments on
adopted regional performance indicators and MAP21/FAST Act regional targets.

No Conflict. This principle directs SCAG in allocating
transportation investments. This principle does not apply to the Project.

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Goals Consistency Analysis
Principle 2. Place high priority for transportation
funding in the region on projects and programs that
improve mobility, accessibility, reliability and safety, and that preserve the existing transportation system
No Conflict. This principle directs SCAG in allocating
transportation system funding. This principle does not
apply to the Project.

Principle 3. Assure that land use and growth
strategies recognize local input, promote
sustainable transportation options, and support
equitable and adaptable communities
Consistent. The Project would create a land use and growth framework that was developed with local input and is
intended to promote a multimodal, sustainable downtown.

Principle 4. Encourage RTP/SCS investments and
strategies that collectively result in reduced
nonrecurrent congestion and demand for single
occupancy vehicle use, by leveraging new
transportation technologies and expanding travel
choices
No Conflict. This principle is directed at investment in transportation technology and transportation choices and does not apply directly to the Project. However, the Project is intended to reduce demand for single occupancy vehicle use and expanding travel choices in the downtown San
Dimas.

Principle 5. Encourage transportation investments
that will result in improved air quality and public
health, and reduced greenhouse gas emissions
Consistent. The project would increase housing options in downtown San Dimas such that residents be more likely to walk and utilize transit that would thereby reduce vehicle trips and associated regional and localized air pollutant and GHG emissions.

Principle 6. Monitor progress on all aspects of the
Plan, including the timely implementation of
projects, programs, and strategies
No Conflict. This principle is directed towards SCAG and not does apply directly to the project.

Principle 7. Regionally, transportation investments
should reflect best-known science regarding climate
change vulnerability, in order to design for long term
resilience
No Conflict. This principle is directed towards SCAG and not does apply directly to the project. However, the Project is intended to provide a framework of downtown San
Dimas that would facilitate long term resilience.

Source: SCAG, Connect SoCal, 2020–2045 RTP/SCS, September 2020.

Table 4.5-3: Consistency with Connect SoCal Land Use Strategies Strategies Consistency Analysis
Sustainable Community Strategy 1: Focus Growth Near Destinations and Mobility Options Sustainable Community Strategy 1a: Emphasize
land use patterns that facilitate multimodal access
to work, educational and other destinations.

Consistent. The land use concepts of the Project
emphasize the multimodal aspect of downtown
San Dimas.

Sustainable Community Strategy 1b: Focus on a
regional jobs/housing balance to reduce commute
times and distances and expand job opportunities
near transit and along center-focused main streets
Consistent. The Project provides for greater
housing opportunities as well as commercial uses
near transit and within the downtown.

Sustainable Community Strategy 1c: Plan for
growth near transit investments and support
implementation of first/last mile strategies
Consistent. The Project provides for growth near
the San Dimas light rail station and includes
first/last mile strategies.

Sustainable Community Strategy 1d: Promote the
redevelopment of underperforming retail
developments and other outmoded nonresidential
uses.

Consistent. The Project is designed to promote
the ongoing vitality of the downtown and foster
redevelopment activity.

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Table 4.5-3: Consistency with Connect SoCal Land Use Strategies Strategies Consistency Analysis
Sustainable Community Strategy 1e: Prioritize infill
and redevelopment of underutilized land to
accommodate new growth, increase amenities and
connectivity in existing neighborhoods.

Consistent. The Project is designed to promote
residential infill development.

Sustainable Community Strategy 1f: Encourage
design and transportation options that reduce the
reliance on number of solo car trips (this could
include mixed uses or locating and orienting close
to existing destinations).

Consistent. The Project is designed to promote
mixed-use, transit supporting development.

Sustainable Community Strategy 1g: Identify ways
to “right size” parking requirements and promote
alternative parking strategies (e.g. shared parking
or smart parking).

Consistent. The Project includes parking
strategies and codes to “right-size” parking within
the downtown.

Sustainable Community Strategy 2: Promote Diverse Housing Choices Sustainable Community Strategy 2a: Preserve and
rehabilitate affordable housing and prevent
displacement.

Consistent. The Project focuses on
redevelopment of underutilized commercial and
vacant property and does not include existing
residential neighborhoods.

Sustainable Community Strategy 2b: Identify
funding opportunities for new workforce and
affordable housing development.

Not Applicable. This strategy is directed toward
SCAG and local jurisdictions funding mechanisms
and does not apply to a downtown specific plan.

Sustainable Community Strategy 2c: Create
incentives and reduce regulatory barriers for
building context-sensitive accessory dwelling units
to increase housing supply.

Not Applicable. This strategy is directed toward
housing policy. The Project is intended to increase
housing supply but does not include existing
residential neighborhoods within which
accessory dwelling units could be considered.

Sustainable Community Strategy 2d: Provide
support to local jurisdictions to streamline and
lessen barriers to housing development that
supports reduction of greenhouse gas emissions.

Consistent. This strategy relates to SCAG support
of local jurisdictions and as such is not applicable
to the Project. However, the Project is intended
to streamline and lessen barriers to housing
development that is within the framework of the
Specific Plan and would therefore support the
reduction of GHG emissions.

Sustainable Community Strategy 3: Leverage Technology Innovations Sustainable Community Strategy 3a: Promote low
emission technologies such as neighborhood
electric vehicles, shared rides hailing, car sharing,
bike sharing and scooters by providing supportive
and safe infrastructure such as dedicated lanes,
charging and parking /drop off space.

Consistent. The Project includes an infrastructure
plan for the downtown which would promote
low-emission transportation choices.

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Table 4.5-3: Consistency with Connect SoCal Land Use Strategies Strategies Consistency Analysis
Sustainable Community Strategy 3b: Improve
access to services through technology such as
telework and telemedicine as well as other
incentives such as a “mobility wallet”, an app-based
system for storing transit and other multi modal
payments.

Not Applicable. This strategy addresses
technology options to reduce transportation
impacts and does not apply to a downtown
specific plan.

Sustainable Community Strategy 3c: Identify ways
to incorporate “micro-power grids” in
communities, for example solar energy, hydrogen
fuel cell power storage and power generation.

Not Applicable. This strategy is directed toward
energy policy and does not apply to a downtown
specific plan such as the Project.

Sustainable Community Strategy 4: Support Implementation of Sustainability Policies Sustainable Community Strategy 4a: Pursue
funding opportunities to support local sustainable
development implementation projects that reduce
greenhouse gas emissions.

Consistent. This strategy relates to SCAG support
of local jurisdictions and as such is not applicable
to the Project. However, the Project is intended
to be a sustainable land use framework that
would support development that would reduce
GHG emissions.

Sustainable Community Strategy 4b: Support
statewide legislation that reduces barriers to new
construction and that incentivizes development
new transit corridors and stations.

Not Applicable. This strategy is directed towards
SCAG support for statewide legislation and does
not apply to the Project.

Sustainable Community Strategy 4c: Support local
jurisdictions in the establishment of Enhanced
Infrastructure Financing Districts (EIFDs),
Community Revitalization and Investment
Authorities (CRIAs), or other tax increment or value
capture tools to finance sustainable infrastructure
and development projects, including parks and
open space.

Consistent. This strategy is directed towards
SCAG support for public finance programs to
support sustainable infrastructure and
development projects. The Project would utilize
local financing programs that would support
sustainable infrastructure and development
projects, including parks and open space.

Sustainable Community Strategy 4d: Work with
local jurisdictions/communities to identify
opportunities and assess barriers to implement
sustainability strategies.

Not Applicable. This strategy addresses SCAG
working with local agencies and does not directly
apply to the Project. Nonetheless, the Project
includes sustainability strategies to support the
long-term vitality of downtown.

Sustainable Community Strategy 4e: Enhance
partnerships with other planning organizations to
promote resources and best practices in the SCAG
region.

Not Applicable. This strategy is directed towards
SCAG actions and does not apply to individual
development projects.

Sustainable Community Strategy 4f: Continue to
support long range planning efforts by local
jurisdictions.

Consistent. This strategy is directed towards
SCAG actions. However, the Project is a long
range planning effort by a by local jurisdictions.

Sustainable Community Strategy 4g: Provide
educational opportunities to local decisionmakers
and staff on new tools, best practices and policies
relating to implementing the Sustainable
Communities Strategy.

Not Applicable. This strategy is directed towards
SCAG actions and does not apply to the Project.

4.5 Greenhouse Gas Emissions
City of San Dimas 4.5-11 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.5-3: Consistency with Connect SoCal Land Use Strategies Strategies Consistency Analysis
Sustainable Community Strategy 5: Promote a Green Region Sustainable Community Strategy 5a: Support
development of local climate adaptation and
hazard mitigation plans, as well as project
implementation that improves community
resiliency to climate change and natural hazards.

Not Applicable. This strategy addresses SCAG
support of local planning efforts related to
community resiliency and does not apply to
directly to the Project. Nevertheless, the Project
represents a long-term planning vision for the
downtown that is intended to improves
community resiliency.

Sustainable Community Strategy 5b: Support local
policies for renewable energy production,
reduction of urban heat islands and carbon
sequestration.

Not Applicable. This strategy addresses SCAG
support for local policies on renewable energy
production, reduction of urban heat islands and
carbon sequestration and does not apply directly
to the Project.

Sustainable Community Strategy 5c: Integrate local
food production into the regional landscape.

Not Applicable. This strategy addresses local food
production in the region and does not apply
directly to the Project.

Sustainable Community Strategy 5d: Promote
more resource efficient development focused on
conservation, recycling and reclamation.

Consistent. The Project would facilitate new
development that would comply with the
CALGreen requirements for resource efficient
building materials and systems.

Sustainable Community Strategy 5e: Preserve,
enhance and restore regional wildlife connectivity.

Not Applicable. This policy addresses regional
wildlife movement and corridors and does not
apply to downtown San Dimas.

Sustainable Community Strategy 5f: Reduce
consumption of resource areas, including
agricultural land.

Consistent. The Project would create a
framework for the future development of
downtown San Dimas which would reduce
development pressure on resource areas such as
agricultural land.

Sustainable Community Strategy 5g: Identify ways
to improve access to public park space.

Consistent. The Project would create a
framework for future development that includes
open space and promote public plazas within the
downtown.

Table 4.5-4: Consistency with Connect SoCal Land Use Tools Tools Consistency Analysis

CENTER FOCUSED PLACEMAKING
Creating dynamic, connected built environments
that support multimodal mobility, reduced reliance
on single-occupancy vehicles, and reduced GHG
emissions is critical throughout the region.

Consistent. The Project is a Specific Plan for
Downtown San Dimas and thus is a centerfocused framework for future development that would be dynamic, connected and multi-modal.

4.5 Greenhouse Gas Emissions
City of San Dimas 4.5-12 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.5-4: Consistency with Connect SoCal Land Use Tools Tools Consistency Analysis

PRIORITY GROWTH AREAS
Priority Growth Areas (PGAs) follow the principles
of center focused placemaking and are locations
where many Connect SoCal strategies can be fully
realized.

Consistent. The Project is located in a Priority
Growth Area, as defined by SCAG.

JOB CENTERS
Job Centers are where regional strategies that
support economic prosperity can be deployed in
catalytic ways. Job Centers have been identified in
all six counties in the SCAG region and represent
areas that have a significantly higher employment
density than surrounding areas. Employment
growth and residential growth are prioritized in
existing Job Centers in order to leverage existing
density and infrastructure.

Consistent. The Project is not identified as a job
center by SCAG; nonetheless, the Project
leverages transit infrastructure to support nearby
Job Centers with new residential development.

TRANSIT PRIORITY AREAS
Transit Priority Areas (TPAs) are Priority Growth
Areas that are within one half mile of existing or
planned ‘major’ transit stops in the region.

Consistent. The Project is located within a Transit
Priority Area, as defined by SCAG.

HIGH QUALITY TRANSIT AREAS
High Quality Transit Areas (HQTAs) are corridorfocused Priority Growth Areas within one half mile of an existing or planned fixed guideway transit stop
or a bus transit corridor where buses pick up
passengers at a frequency of every 15 minutes (or
less) during peak commuting hours.

Consistent. The Project is located within a Transit
Quality Transit Area, as defined by SCAG.

NEIGHBORHOOD MOBILITY AREAS
Neighborhood mobility area (NMAs) focus on
creating, improving, restoring and enhancing safe
and convenient connections to schools, shopping,
services, places of worship, parks, greenways and
other destinations. NMAs are Priority Growth Areas
with robust residential to non-residential land use
connections, high roadway intersection densities
and low-to-moderate traffic speeds.

Consistent. The Project is located within a
Neighborhood mobility area, as defined by SCAG.

The Project would improve safe and convenient
connections to between residential, commercial,
public facilities and transit.

LIVABLE CORRIDORS
The Livable Corridor strategy encourages local
jurisdictions to plan and zone for increased density
at nodes along key corridors, and to “redevelop”
single story under-performing retail with welldesigned, higher density housing and employment centers. Growth at strategic nodes along key
corridors, many of which are within HQTAs, will
make transit a more convenient and viable option.

Consistent. The Project includes increased
density throughout the plan, including along
Bonita Avenue, the key corridor through the
center of San Dimas.

4.5 Greenhouse Gas Emissions
City of San Dimas 4.5-13 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.5-4: Consistency with Connect SoCal Land Use Tools Tools Consistency Analysis

SPHERES OF INFLUENCE
Local Agency Formation Commissions, or LAFCos,
are given the authority to determine SOIs for all
local governmental agencies, and each county in
the SCAG region has an associated LAFCo. An SOI is
a planning boundary outside of a local agency’s
legal boundary (such as the city limit line) that
designates the agency’s probable future boundary
and service area.

Not Applicable. The Project is within the City of
San Dimas and is not part of a Sphere of
Influence.

GREEN REGION
A sustainable, “green” region requires that the built
environment and natural resource areas coexist in
a well-balanced land use pattern that encourages
mutual co-benefits.

Consistent. The Project would support new
housing and commercial development within a
Priority Growth Area and away from natural and
farmlands on the urban edges.

TRANSFER OF DEVELOPMENT RIGHTS
Transfer of Development Rights (TDR) is a marketbased planning tool to support growth in locally identified “receiving districts” in lieu of growth in
identified “sending districts.”
Not Applicable. The City of San Dimas has not
identified “receiving districts” or “sending
districts” for transfer of development rights.

URBAN GREENING
Urban Greening is a multi-benefit land use strategy
that improves the relationship between the built
and natural environment.

Consistent. The Project would include design
standards that increase the number of trees on
private development and street trees within the
Project area.

GREENBELTS & COMMUNITY SEPARATORS
Greenbelts and community separators can serve as
contiguous areas between jurisdictions that
support projected regional growth, promote land
conservation, and avert unchecked urbanization.

Not Applicable. The Project is focused on
downtown San Dimas and not areas between
jurisdictions.

As shown in the preceding tables, the Project is consistent with and supportive of the goals, polices and tools of Connect SoCal. As such, it would not conflict with the regional effort to reduce the emissions of greenhouse gases and would not generate greenhouse gas emissionsthat would be considered significant in a regional or state perspective. Furthermore, future development that results from the Project would be required to comply with applicable building regulations such as the California Green Building Standards Code and California’s Title 24 Building Energy Efficiency Standards, that would further reduce GHG emissions of future projects. Therefore, the GHG impacts of the Project would be less than significant.

Cumulative Impacts
GHG emissions are cumulative in nature, as their impact is associated with global climate change. As such, the evaluation of Project impacts is also the determinant of whether a Project has a considerable

4.5 Greenhouse Gas Emissions
City of San Dimas 4.5-14 Community Development Department Downtown Specific Plan Draft EIR June 2024
contribution to cumulative effects. The analysis herein determined that the implementation of the proposed Project would not result in significant adverse impacts related to the emissions of greenhouse gases. As a result, the Project would also not have a considerable contribution to cumulative GHG impacts.

4.5.4 MITIGATION
As impacts would be less than significant, no mitigation is necessary.

City of San Dimas 4.6-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.6 HAZARDS AND HAZARDOUS MATERIALS

4.6.1 THRESHOLDS OF SIGNIFICANCE
The following thresholds for determining the significance of impacts related to Hazards and Hazardous Materials are derived from the environmental checklist form contained in Appendix G of the most recent update of the State CEQA Statutes and Guidelines.
a. Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials?
b. Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? c. Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? d. Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment?
e. For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area? f. Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan?
g. Expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires?

4.6.3 ENVIRONMENTAL SETTING
Hazardous Materials
Section 25501(m) of the California Health and Safety Code defines a “hazardous material” as:

A material that, because of its quantity, concentration, or physical or chemical characteristics, poses a significant present or potential hazard to human health and safety or to the environment if released into the workplace or the environment. “Hazardous Materials” include, but are not limited to, hazardous substances, hazardous wastes, and any materials which a handler or the unified program agency has a reasonable basis for believing that it would be injurious to the health and safety of persons or harmful to the environment if released into the workplace or environment.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-2 Community Development Department Downtown Specific Plan Draft EIR June 2024
“Hazardous waste” is any hazardous material that is abandoned, discarded, or recycled, as defined by Sections 25117 and 25124 of the California Health and Safety Code. In addition, hazardous waste may occasionally be generated by actions that change the composition of previously nonhazardous materials.

The criteria used to characterize a material as hazardous include ignitability, toxicity, corrosivity, reactivity, radioactivity, or bioactivity.

As will be discussed in more detail below, hazardous materials and wastes are defined and regulated in the United States by federal, state, and local regulations, including those administered by the US Environmental Protection Agency (US EPA), the California Environmental Protection Agency (Cal/EPA), the US Occupational Safety and Health Administration, the US Department of Transportation, the US Nuclear Regulatory Commission, and various other agencies. Hazardous materials include hazardous wastes and, in the discussion, below (except as noted) hazardous materials refers to both hazardous materials and wastes.

Public health is potentially at risk whenever hazardous materials are, or would be, used and when hazardous wastes are disposed of, including transportation of hazardous materials and wastes. It is necessary to differentiate between the “hazard” of these materials and the acceptability of the “risk” they pose to human health and the environment. A hazard is any situation that has the potential to cause damage to human health and the environment. The California Department of Toxic Substances Control (DTSC) determines the risk to health and public safety by the probability of exposure, in addition to the inherent toxicity of a material.

Factors that can influence health effects when human beings are exposed to hazardous materials or wastes include: the dose the person is exposed to, the frequency of exposure, the duration of exposure, the exposure pathway (route by which a chemical enters a person’s body), and the individual’s unique biological susceptibility.

Hazardous Waste Generation and Management
There are four general categories of waste management: source reduction, recycling, treatment, and residuals disposal. All of these activities can occur on-site at the location where they are generated.

Recycling, treatment, and disposal can also occur off-site but require additional intermediate support to store and transport the waste.

The generation and handling of hazardous waste in the City is overseen by multiple agencies including: US EPA; California Department of Toxic Substances Control, California Department of Resources, Recycling and Recovery (CalRecycle), Los Angeles County Department of Public Works, Sanitation Districts of Los Angeles County, and the Los Angeles County Fire Department. Businesses that generate hazardous waste

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-3 Community Development Department Downtown Specific Plan Draft EIR June 2024
are either Large-Quantity Generators (e.g., heavy industrial or commercial facilities) or Small-Quantity Generators (e.g., dry cleaners, automotive repair shops, etc.); these businesses require an EPA identification number used to monitor and track hazardous waste activities.

Certain land uses can indicate that there is potential for generating hazardous materials or waste, or that existing hazardous materials or waste may be present (for example: industrial uses, gas stations, and dry cleaners). Hazardous materials can also be used and generated during construction activities. Common hazardous materials that are typically present on construction sites include oil, transmission fluids, fuels, solvents, paints, asphalt, and adhesives. A variety of federal, state, and local regulations require best management practices to be implemented to ensure that these wastes are not released into the environment.

Transportation of Hazardous Materials
The transportation of hazardous materials within the State of California is subject to various federal, state, and local regulations. It is illegal to transport explosives or inhalation hazards on any public highway not designated for that purpose, unless the use of the highway is required to permit loading or delivery of such materials (California Vehicle Code Sections 31602(b), 32104(a)). The California Highway Patrol (CHP) designates through routes to be used for the transportation of hazardous materials. Transportation of hazardous materials in the City is restricted to this route except in cases where additional travel is required from that route to deliver or receive hazardous materials to and from users.

There are several risks associated with the transportation of hazardous materials. Transport of hazardous materials via truck, rail, and other modes involves a degree of risk of accident and release. The use of hazardous materials and the generation of hazardous waste in the construction and maintenance of the transportation system are other avenues for risk or exposure. Past disposal of hazardous materials in a manner that creates residual contamination of soil or water can be a source of risk when such sites are disturbed in the course of construction of transportation projects and development. Each of these avenues is discussed below.

Hazardous materials move through the City by a variety of modes: truck, rail, air, and pipeline. Any given shipment of hazardous materials can involve one or more movements, or trip segments, that can occur by different modes. For instance, a shipment might arrive at a port by ship (out of the City) and be picked up by a truck, with a transfer to rail, and a final delivery by truck again (for a total of four movements). Each movement of hazardous materials implies a degree of risk, depending on the material being moved, the mode of transport, and numerous other factors.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-4 Community Development Department Downtown Specific Plan Draft EIR June 2024
Vehicles transporting hazardous materials through the City use many of the same freeways, arterials, and local streets as other traffic in the region. This creates a risk of accidents and associated release of hazardous materials that could create a risk for drivers and for people living, working, and going to school along these routes. A similar risk exists for use of rail for hazardous materials transport. Rail line maintenance is the responsibility of each private company that owns and operates each line. Rail routes pass through urban areas and near sensitive land uses such as schools, hospitals, and residential areas.

Rail shipments through urban areas and on local rail spurs usually travel at slower speeds than in rural areas reducing the possibility of major safety related accidents. In addition, shipping by rail is often safer than shipping by truck because rail tankers can reduce the number of trucks on the road hauling hazardous materials by four to 10 times, reducing the chances of trucking related accidents.

Pipelines tend to be protected because they are buried and result in relatively low risk, although they could be affected by seismic or other activity that could cause rupture. According to the USDOT, Hazardous Materials Information System, in 2014, highways accounted for the largest share of hazardous materials incidents, with a total of 15,156 incidents or 88 percent of total incidents.

In addition to the CHP designated routes, the City has designed and designated various roadways as truck routes to provide for the regulated movement of trucks through the City. Arrow Highway provide the Specific Plan Area with direct access to truck routes. However, these transportation routes are also used to transport hazardous materials (among other materials/freight) from suppliers to users. Transportation accidents involving hazardous materials could occur on designated truck routes Hazardous Waste Sites
GeoTracker
GeoTracker is the California State Water Resources Control Board’s (SWRCB) data management system for managing sites that impact groundwater, especially those that require groundwater cleanup (Underground Storage Tanks, Department of Defense, Site Cleanup Program) as well as permitted facilities such as operating underground storage tanks (USTs) and land disposal sites.

The Geographic Environmental Information Management System (GEIMS) is a data warehouse that tracks regulatory data about underground fuel tanks, fuel pipelines, and public drinking water supplies using GeoTracker. GeoTracker and GEIMS were developed pursuant to a mandate by the California State Legislature (AB 592, SB 1189) to investigate the feasibility of establishing a statewide GIS for leaking underground fuel tank (LUFT) sites. The GeoTracker database provides lists of several site types including Leaking Underground Storage Tank (LUST) Cleanup Sites, Other Cleanup Sites, Land Disposal Sites, Military Sites, Waste Discharge Report (WDR) Sites, and Permitted Underground Storage Tank (UST) Facilities.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-5 Community Development Department Downtown Specific Plan Draft EIR June 2024
EnviroStor
The DTSC’s EnviroStor database is an online search and Geographic Information System (GIS) tool.

EnviroStor provides access to detailed information on hazardous waste permitted and corrective action facilities, as well as existing site cleanup information. EnviroStor allows a search for information on investigation, cleanup, permitting, and/or corrective actions that are planned, being conducted or have been completed under DTSC’s oversight. The EnviroStor database provides information on a variety of cleanup sites and permitted hazardous materials sites. The cleanup sites include Federal Superfund (National Priority List), State Response, Voluntary Cleanup, School Cleanup, Corrective Action, as well as several others.

4.6.4 REGULATORY FRAMEWORK
Federal
Clean Air Act
The Clean Air Act (CAA) is the comprehensive federal law that regulates air emissions from stationary and mobile sources. Among other things, this law authorizes the United States Environmental Protection Agency (US EPA) to establish National Ambient Air Quality Standards (NAAQS) to protect public health and public welfare and to regulate emissions of hazardous air pollutants. One of the goals of the Act was to set and achieve NAAQS in every state by 1975 in order to address the public health and welfare risks posed by certain widespread air pollutants. The setting of these pollutant standards was coupled with directing the states to develop state implementation plans (SIPs), applicable to appropriate industrial sources in the state, in order to achieve these standards. The Act was amended in 1977 and 1990 primarily to set new goals (dates) for achieving attainment of NAAQS, since many areas of the country had failed to meet the deadlines.

Section 112 of the Clean Air Act addresses emissions of hazardous air pollutants. The 1990 Clean Air Act Amendments revised Section 112 to first require issuance of technology-based standards for major sources and certain area sources. “Major sources” are defined as a stationary source or group of stationary sources that emit or have the potential to emit 10 tons per year or more of a hazardous air pollutant or 25 tons per year or more of a combination of hazardous air pollutants. An “area source” is any stationary source that is not a major source. For major sources, Section 112 requires that US EPA establish emission standards that require the maximum degree of reduction in emissions of hazardous air pollutants. These emission standards are commonly referred to as “maximum achievable control technology” or “MACT” standards. Eight years after the technology-based MACT standards are issued for a source category; US EPA is required to review those standards to determine whether any residual risk exists for that source

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-6 Community Development Department Downtown Specific Plan Draft EIR June 2024
category and, if necessary, revise the standards to address such risk. (All impacts related to air quality are addressed in Section 4.1, Air Quality).

Clean Water Act
The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters. Under the CWA, US EPA has implemented pollution control programs such as setting wastewater standards for industry. Water quality standards for all contaminants in surface waters were also established. The CWA made it unlawful to discharge any pollutant from a point source into navigable waters, unless a permit was obtained. US EPA’s National Pollutant Discharge Elimination System (NPDES) permit program controls discharges. Point sources are discrete conveyances such as pipes or man-made ditches. Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters.

Environmental Protection Agency Regulations
The US EPA’s mission is to protect human health and the environment. The US EPA takes action to reduce risks associated with exposure to chemicals in commerce, indoor and outdoor environments, and products and food. The US EPA continues to oversee the introduction and use of pesticides, improve their Integrated Risk Information System (IRIS) program, reduce radon risks, identify and address children's health risks in schools and homes, and improve chemical management practices. Oversight of chemical storage and manufacturing in coordination with their interagency partners remains a key focus of the US EPA, as well as efforts to reduce urban air toxics.

Comprehensive Environmental Response, Compensation, and Liability Act The Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA” or “Superfund”) provides a federal “superfund” to clean up uncontrolled or abandoned hazardous waste sites as well as accidents, spills, and other emergency releases of pollutants and contaminants into the environment.

Through CERCLA, US EPA was given power to seek out those parties responsible for any release and assure their cooperation in the cleanup. US EPA cleans up orphan sites when potentially responsible parties cannot be identified or located, or when they fail to act. Through various enforcement tools, US EPA obtains private party cleanup through orders, consent decrees, and other small party settlements. US EPA also recovers costs from financially viable individuals and companies once a response action has been completed.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-7 Community Development Department Downtown Specific Plan Draft EIR June 2024
The US EPA is authorized to implement the Act in all 50 states and US territories. Superfund site identification, monitoring, and response activities in states are coordinated through the state environmental protection or waste management agencies.

The Superfund Amendments and Reauthorization Act (SARA) of 1986 reauthorized CERCLA to continue cleanup activities around the country. Several site-specific amendments, definitions clarifications, and technical requirements were added to the legislation, including additional enforcement authorities. This included Title III of SARA authorized the Emergency Planning and Community Right-to-Know Act (EPCRA); this act is discussed in further detail below.

Superfund Amendments and Reauthorization Act of 1986
The Superfund Amendments and Reauthorization Action (SARA) of 1986 reauthorized CERCLA to continue cleanup activities around the country. Several site-specific amendments, definitions, clarifications, and technical requirements were added to the legislation, including additional enforcement authorities.

Hazardous Material Transportation Act
The Hazardous Materials Transportation Act, as amended, is the basic statute regulating hazardous materials transportation in the United States. The purpose of the law is to provide adequate protection against the risks to life and property inherent in transporting hazardous materials in interstate commerce.

This law gives the US Department of Transportation (DOT) and other agencies the authority to issue and enforce rules and regulations governing the safe transportation of hazardous materials.

Occupational Safety and Health Act of 1970
The Occupational Safety and Health Act, which is implemented by OSHA, contains provisions with respect to hazardous materials handling. Federal OSHA requirements, as set forth in Title 29 of the Code of Federal Regulations (CFR) Section 1910, et seq., are designed to promote worker safety, worker training, and a worker’s right–to-know. In California, OSHA has delegated the authority to administer OSHA regulations to the State of California.

Title 49 of the CFR, which contains the regulations set forth by the Hazardous Materials Transportation Act of 1975, specifies additional requirements and regulations with respect to the transport of hazardous materials. Title 49 of the CFR requires that every employee who transports hazardous materials receive training to recognize and identify hazardous materials and become familiar with hazardous materials requirements. Drivers are also required to be trained in operations of their equipment and commodity specific requirements.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-8 Community Development Department Downtown Specific Plan Draft EIR June 2024
Resource Conservation and Recovery Act
The Resource Conservation and Recovery Act (RCRA) gives the EPA the authority to control hazardous waste from the “cradle-to-grave.” This includes the generation, transportation, treatment, storage, and disposal of hazardous waste by “large-quantity generators” (1,000 kilograms/month or more). Under RCRA regulations, hazardous wastes must be tracked from the time of generation to the point of disposal. At a minimum, each generator of hazardous waste must register and obtain a hazardous waste activity identification number. If hazardous wastes are stored for more than 90 days or treated/disposed of at a facility, any treatment, storage, or disposal unit must be permitted under RCRA. Additionally, all hazardous waste transporters are required to be permitted and must have an identification number. RCRA allows individual states to develop their own program for the regulation of hazardous waste as long as it is at least as stringent as RCRA. In California, the US EPA has delegated RCRA enforcement to the State of California.

Department of Transportation Regulations
The Secretary of the Federal Department of Transportation receives the authority to regulate the transportation of hazardous materials from the Hazardous Materials Transportation Act (HMTA), as amended and codified in 49 USC 5101 et seq. The Secretary is authorized to issue regulations to implement the requirements of 49 USC The Pipeline and Hazardous Materials Safety Administration (PHMSA) (formerly the Research and Special Provisions Administration [RSPA]) was delegated the responsibility to write the hazardous materials regulations, which are contained in 49 CFR Parts 100180.

Toxic Substances Control Act
Congress enacted the Toxic Substances Control Act (TSCA) of 1976 to give US EPA the ability to track the approximately 75,000 industrial chemicals currently produced or imported into the United States. The US EPA repeatedly screens these chemicals and can require reporting or testing of those that may pose an environmental or human-health hazard. The US EPA can ban the manufacture and import of those chemicals that pose an unreasonable risk.

Research and Special Programs Administration Regulations The Research and Special Programs Administration Regulations (RSPA) regulations cover definition and classification of hazardous materials, communication of hazards to workers and the public, packaging, and labeling requirements, operational rules for shippers, and training. They apply to interstate, intrastate, and foreign commerce by air, rail, ships, and motor vehicles, and also cover hazardous waste shipments. The Federal Highway Administration (FHWA) is responsible for highway routing of hazardous materials and highway safety permits. The US Coast Guard regulates bulk transport by vessel. The hazardous material

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-9 Community Development Department Downtown Specific Plan Draft EIR June 2024
regulations include emergency response provisions, including incident reporting requirements. Reports of major incidents go to the National Response Center, which in turn is linked with CHEMTREC, a service of the chemical manufacturing industry that provides details on most chemicals shipped in the US.

Emergency and Community Right to Know Act
The Emergency and Community Right to Know Act (EPCRA) was enacted by Congress as the national legislation on community safety. This law was designated to help local communities protect public health, safety, and the environment from chemical hazards. EPCRA was passed in response to concerns regarding the environmental and safety hazards posed by the storage and handling of toxic chemicals. EPCRA establishes requirements for federal, state, and local governments, tribes and industry regarding emergency planning and “Community Right-to-Know” reporting on hazardous and toxic chemicals. The Community Right-to-Know provisions help increase the public’s knowledge and access to information on chemicals at individual facilities, their uses, and releases into the environment. States and communities, working with facilities, can use the information to improve chemical safety and protect public health and the environment. To implement EPCRA, Congress required each state to appoint a State Emergency Response Commission (SERC). The SERCs were required to divide their states into Emergency Planning Districts and to name a Local Emergency Planning Committee for each district.

State
California Environmental Protection Agency and California Department of Toxic Substances Control
The California EPA (Cal/EPA) includes the DTSC, whose mission it is to protect California's people and environment from harmful effects of toxic substances through the restoration of contaminated resources, enforcement, regulation, and pollution prevention. The DTSC regulates hazardous waste, cleans-up existing contamination, and looks for ways to reduce the hazardous waste produced in California.

Approximately 1,000 scientists, engineers, and specialized support staff ensure that companies and individuals handle, transport, store, treat, dispose of, and clean-up hazardous wastes appropriately.

Through these measures, DTSC contributes to greater safety for all Californians, and less hazardous waste reaches the environment.

DTSC regulates hazardous waste in California primarily under the authority of RCRA and the California Health and Safety Code. The DTSC regulates hazardous waste, cleans up existing contamination, and researches ways to reduce the hazardous waste produced in California. In addition, the DTSC develops legislation, coordinates with lawmakers, and responds to constituent complaints. The regulations spell out what those who handle hazardous waste must do to comply with the laws.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-10 Community Development Department Downtown Specific Plan Draft EIR June 2024
Statewide, DTSC cleans-up or oversees approximately 220 hazardous substance release sites at any given time and completes an average of 125 cleanups each year. Ensuring compliance through inspection and enforcement is an important part of effectively regulating hazardous waste. DTSC conducts roughly 200 inspections a year. DTSC‘s Criminal Investigations Branch has the only law enforcement officers in the Cal/EPA. These peace officers, with the powers of arrest, and search and seizure, investigate alleged criminal violations of the Hazardous Waste Control Law. They work closely with district attorneys' offices, the federal Environmental Protection Agency, the Federal Bureau of Investigation, and law enforcement personnel in other states.

The California Hazardous Materials Release Response Plans and Inventory Law of 1985 (Business Plan Act) requires that any business that handles hazardous materials prepare a business plan, which must include:
• Details, including floor plans, of the facility and business conducted at the site; • An inventory of hazardous materials that are handled or stored on-site; • An emergency response plan; and
• A safety and emergency-response training program for new employees with annual refresher courses.

California Occupational Safety and Health Administration Regulations The California Occupational Safety and Health Administration Regulations (Cal/OSHA) has set forth work requirements for disturbance of Asbestos-Containing Construction Materials (ACCMs) including removal operations for all types of ACCMs. In addition, the agency has developed standards for general industry and the construction industry hazardous waste operations and emergency response. Cal/OSHA ensures that employers must have controls to reduce and monitor exposure levels of hazardous materials, an informational program describing any exposure during operations and the inspection of drums and containers prior to removal or opening. Decontamination procedures and emergency response plans must be in place before employees begin working in hazardous waste operations.

California Office of Emergency Services Regulations
The California Office of Emergency Services (CAL OES) Hazardous Materials (HazMat) Section under the Fire and Rescue Division coordinates statewide implementation of hazardous materials accident prevention and emergency response programs for all types of hazardous materials incidents and threats.

In response to any hazardous materials emergency, the section staff is called upon to provide state and local emergency managers with emergency coordination and technical assistance.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-11 Community Development Department Downtown Specific Plan Draft EIR June 2024
Accidental Release Prevention Law
The state’s Accidental Release Prevention Law provides for consistency with federal laws (i.e., the Emergency Preparedness and Community Right-to-Know Act and the Clean Air Act) regarding accidental chemical releases and allows local oversight of both the state and federal programs. State and federal laws are similar in their requirements; however, the California threshold planning quantities for regulated substances are lower than the federal quantities. Local agencies may set lower reporting thresholds or add additional chemicals to the program. The Accidental Release Prevention Law is implemented by the Certified Unified Program Agency (CUPA) and requires that any business, where the maximum quantity of a regulated substance exceeds the specified threshold quantity, register with the County as a manager of regulated substances and prepare a risk management plan. A risk management plan must contain an offsite consequence analysis, a five-year accident history, an accident prevention program, an emergency response program, and a certification of the truth and accuracy of the submitted information. Businesses submit their plans to the CUPA, which makes the plans available to emergency response personnel. The business plan must identify the type of business, location, emergency contacts, emergency procedures, mitigation plans, and chemical inventory at each location.

Hazardous Waste Control Act
The Hazardous Waste Control Act created the state hazardous waste management program, which is similar to but more stringent than the federal Resource Conservation and Recovery Act program. The act is implemented by regulations contained in Title 26 of the CCR, which describes the following required aspects for the proper management of hazardous waste: identification and classification; generation and transportation; design and permitting of recycling, treatment, storage, and disposal facilities; treatment standards; operation of facilities and staff training; and closure of facilities and liability requirements.

These regulations list more than 800 materials that may be hazardous and establish criteria for identifying, packaging, and disposing of such waste. Under the Hazardous Waste Control Act and Title 26, the generator of hazardous waste must complete a manifest that accompanies the waste from generator to transporter to the ultimate disposal location. Copies of the manifest must be filed with DTSC.

Unified Hazardous Waste and Hazardous Materials Management Regulatory Program
The Unified Hazardous Waste and Hazardous Materials Management Regulatory Program (Unified Program) required the administrative consolidation of six hazardous materials and waste programs (Program Elements) under one agency, a CUPA. The Program Elements consolidated under the Unified Program are: Hazardous Waste Generator and On-site Hazardous Waste Treatment Programs (a.k.a. Tiered Permitting); Aboveground Petroleum Storage Tank Spill Prevention Control and Countermeasure Plan

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-12 Community Development Department Downtown Specific Plan Draft EIR June 2024
(SPCC); Hazardous Materials Release Response Plans and Inventory Program (a.k.a. “Hazardous Materials Disclosure” or “Community-Right-To-Know”); California Accidental Release Prevention Program (Cal ARP); UST Program; and Uniform Fire Code Plans and Inventory Requirements. The Unified Program is intended to provide relief to businesses complying with the overlapping and sometimes conflicting requirements of formerly independently managed programs. The Unified Program is implemented at the local government level by CUPAs. Most CUPAs have been established as a function of a local environmental health or fire department. Some CUPAs have contractual agreements with another local agency, a participating agency, which implements one or more Program Elements in coordination with the CUPA.

Hazardous Materials Release Response Plans and Inventory Act of 1985 The Hazardous Materials Release Response Plans and Inventory Act, also known as the Business Plan Act, requires businesses using hazardous materials to prepare a plan that describes their facilities, inventories, emergency response plans, and training programs. Hazardous materials are defined as unsafe raw or unused materials that are part of a process or manufacturing step. They are not considered hazardous waste. Health concerns pertaining to the release of hazardous materials, however, are similar to those relating to hazardous waste.

Hazardous Waste Source Reduction and Management Review Act of 1989 This Act requires generators of 12,000 kilograms/year of typical/operational hazardous waste to conduct an evaluation of their waste streams every four years and to select and implement viable source reduction alternatives. This Act does not apply to nontypical hazardous waste (such as asbestos and polychlorinated biphenyls).

California Vehicle Code
The California Vehicle Code (Title 13 of the CCR) establishes regulations for motor carrier transport of hazardous materials. For example, all motor carrier transporters of hazardous materials are required to have a Hazardous Materials Transportation license issued by the California Highway Patrol. In addition, placards identifying that hazardous materials are being transported must be displayed on the vehicle.

California Health and Safety Code
The transport of hazardous waste materials is further governed by the California Health and Safety Code Section 25163 and Title 22, Chapter 13, of the CCR. Specifically, Section 25163 of the California Health and Safety Code requires transporters of hazardous waste to hold a valid registration issued by the DTSC in his/her possession while transporting hazardous waste. Additionally, Title 22, Chapter 13 of the CCR includes a number of requirements, which include, but are not limited to, the following:

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-13 Community Development Department Downtown Specific Plan Draft EIR June 2024
• Transporters shall not transport hazardous waste without first receiving an identification number and a registration certificate from DTSC
• Registration as a hazardous waste transporter expires annually, on the last day of the month in which the registration was issued
• To be registered as a hazardous waste transporter, an application must be submitted • Hazardous waste shall not be accepted for transport without a Uniform Hazardous Waste Manifest that has been properly completed and signed by generator and transporter • Hazardous waste shall be delivered to authorized facilities only Local
South Coast Air Quality Management District
The South Coast Air Quality Management District (SCAQMD) works with the California Air Resources Board (CARB) and is responsible for developing and implementing rules and regulations regarding air toxics on a local level. The SCAQMD establishes permitting requirements, inspects emission sources, and enforces measures through educational programs and/or fines. The SCAQMD and regulations related to air quality are discussed in detail in Section 4.1, Air Quality.

Los Angeles County Health Care Agency- Environmental Health Care Division The Certified Unified Program Agency with jurisdiction over the City of Claremont is the County of Los Angeles Fire Department Health Hazardous Materials Division (HHMD). The HHMD became a CUPA in 1997. The HHMD coordinates the regulation of hazardous materials and hazardous wastes in Los Angeles County through the following programs:
• Aboveground Petroleum Tank
• California Accidental Release Prevention (CalARP)
• Hazardous Waste
• Hazardous Materials (Hazardous Material Handler Permit Requirements) • Underground Storage Tank
City Fire Agencies within Los Angeles County have joined in partnership with the CUPA as Participating Agencies (PAs). The CUPA provides its regulated businesses several convenient benefits such as a single point of contact for permitting, billing, and inspections; uniformity and consistency in enforcement of regulations; and a single fee system incorporating all of the applicable fees from the CUPA programs. The HHMD provides detailed guidelines to respond to emergency hazardous materials spills or releases and abandonment.

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-14 Community Development Department Downtown Specific Plan Draft EIR June 2024
The Hazardous Material Handler Permit Requirements indicates that businesses that handle hazardous materials in quantities equal to or greater than 55 gallons of a liquid, 500 pounds of a solid, or 200 cubic feet of compressed gas, or extremely hazardous substances above the threshold planning quantity, are considered a hazardous materials handler and to report appropriate information (i.e. emergency response and contingency plan and employee training plan) in the California Environmental Reporting System (CERS). Compliance with the Hazardous Materials Handler Permit Requirements would ensure that all hazardous wastes generated by existing and proposed uses are properly handled, recycled, treated, stored, and disposed. This program involves inspection of facilities that generate hazardous waste, evaluation of hazardous waste generating industries, investigation of reports of illegal hazardous waste disposal, and response to emergency hazardous chemical spills. The CalARP program aims to prevent accidental releases of hazardous materials that could cause harm to the public or environment.

Standardized Emergency Management System Multi-Hazard Functional Plan The Basic Plan of the Standardized Emergency Management System (SEMS) Multi- Hazard Functional Plan (MHFP) is outlined with different phases. The preparedness phase with increased readiness, response phase with pre-emergency and emergency response, recovery phase, and mitigation phase. These phases provide detailed information to handle disaster events whether they are peacetime emergencies such as natural or technological or national security emergencies such as food and petroleum shortages or nuclear attack. Assessments of the major threats to the City of Claremont are included in the SEMS MHFP which includes earthquake, hazardous materials from spills during transit, flooding, dam failure, and many others. Each threat is assessed for its impact to the City including damage to vital service systems, transit routes, and fuel access. An appropriate response to the threat is also discussed.

4.6.5 IMPACT ANALYSIS
a. Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials?
Implementation of the DTSP would result in an increase in density and population through development and redevelopment of properties within the Specific Plan area. Routine transportation of hazardous materials, including through traffic, poses a risk to residents within the City as a result of potential accidents involving trucks, rail, and other modes that are used to transport hazardous materials and wastes and are shared with the public. As the DTSP is a programmatic, planning-level policy document, the Project would not directly initiate or entitle any new development. Future development initiated pursuant to the DTSP could result in the construction of residential uses and other sensitive receptors adjacent to existing land uses such as dry cleaners or gas stations that require the routine transport, use, and disposal of hazardous materials. The proposed land uses, which do not include industrial uses, do not generally

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-15 Community Development Department Downtown Specific Plan Draft EIR June 2024
involve the routine use, transport, or disposal of significant amounts of hazardous materials, including hazardous chemical, radioactive, and biohazardous materials.

The operation of land uses that use, create, or dispose of hazardous materials is regulated and monitored by federal, state, and local regulations and policies. Within the Specific Plan area specifically, future development would be subject to compliance with the programs administered by the City of San Dimas and the Los Angeles County Health and Hazardous Materials Division (HHMD) Certified Unified Program Agency (CUPA). The owners or operators of businesses that handle or store hazardous materials equal to or above the reportable quantities would be subject to compliance with the CUPA programs detailed above. These programs, as well as other federal, state, and local regulations and policies, provide a high level of protection to the public and the environment. As such, impacts from routine use, transport, or disposal of hazardous materials would be less than significant. b. Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? The land uses that would be allowed by the DTSP do not include industrial uses and generally do not involve the routine use, transport, or disposal of significant amounts of hazardous materials. As the DTSP is a programmatic, planning-level policy document, the Project would not directly initiate or entitle any new development projects. Future development initiated pursuant to the DTSP could result in the construction of residential uses and other sensitive receptors adjacent to existing land uses such as dry cleaners or gas stations that require the routine transport, use, and disposal of hazardous materials. The operation of land uses that use, create, or dispose of hazardous materials is regulated and monitored by federal, state, and local regulations and policies. These materials would be stored, used, and disposed of in accordance with applicable regulations. Compliance with these regulations and guidelines would reduce hazards from hazardous materials to the public and the environment. As such, impacts associated with upset or accident conditions involving the release of hazardous materials would be less than significant. c. Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? The nearest school to the DTSP planning area is Fred Ekstrand Elementary School, located approximately

0.25 miles to the north. As the DTSP is a programmatic, planning-level policy document, the Project would not directly initiate or entitle any new development projects. The proposed Project would not emit hazardous emissions or include the handling of hazardous or acutely hazardous materials, substances, and/or wastes within one-quarter mile of an existing or proposed school. Any transport of hazardous substances or materials to-and-from the Project site that may occur during construction and operation of the Project would be required to comply with applicable federal, State, and local regulations intended to reduce public safety hazards. Compliance with these regulations and guidelines would reduce hazards

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-16 Community Development Department Downtown Specific Plan Draft EIR June 2024
from hazardous materials to the public and the environment. The proposed Project would not pose a significant risk of hazardous emissions or significant handling of hazardous materials or substances within one-quarter mile of an existing or proposed school and impacts would be less than significant. d. Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment?
California Government Code Section 65962.5 references the following types of hazardous materials sites:
hazardous waste facilities; hazardous waste discharges for which the State Water Quality Control Board has issued certain types of orders; public drinking water wells containing detectable levels of organic contaminants; underground storage tanks with reported unauthorized releases; and solid waste disposal facilities from which hazardous waste has migrated. The EDR Radius Map Report records search, see Appendix C, includes hazardous materials sites compiled pursuant to Government Code Section 65962.5.

Further, information on hazardous materials sites pursuant to Government Code Section 65962.5 is compiled on the websites of the State Department of Toxic Substance Control (DTSC), the State Water Resources Control Board, and California Environmental Protection Agency (CalEPA).

The records search identified the DTSP planning area on the Hazardous Waste Information System (HAZNET) site, the National Pollution Discharge Elimination System (NPDES) site, and the Hazardous Waste Tracking System (HWTS) site. Any transport of hazardous substances or materials to-and-from the Project site that may occur during construction and operation of the Project would be required to comply with applicable federal, State, and local regulations intended to reduce public safety hazards. Compliance with these regulations and guidelines would reduce hazards from hazardous materials to the public and the environment. As such, all potentially hazardous materials would be used and stored in compliance with applicable federal, State, and local regulations.

The DTSP planning area includes eight Cortese List sites identified in the RWQCB GeoTracker database.

The provisions in Government Code Section 65962.5 are commonly referred to as the “Cortese List”. The list, or a site’s presence on the list, has bearing on the local permitting process as well as on compliance with the California Environmental Quality Act (CEQA). Further, two sites listed on the DTSC EnviroStor database are also within the DTSP planning area. Cleanup sites designated as completed have received a closure letter or other formal case closure decision from the relevant regulatory agency. The sites listed, which include automobile service stations, automobile repair, city service facilities, and a machinery equipment company, are detailed in Table 4.6-1: GeoTracker and EnviroStor Sites below. One site, located at 304 W. Bonita Avenue, is listed by both the RWQCB GeoTracker and DTSC EnviroStor databases. All of the sites listed in the RWQCB GeoTracker and DTSC EnviroStor databases have been determined to be fully remediated, and thus would not result in significant hazards to the public or environment.

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City of San Dimas 4.6-17 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.6-1: GeoTracker and EnviroStor Sites
GeoTracker
Name Media Contaminants Status Status Date Address
Shell #204-6774-0369 Soil Diesel Completed -
Closed 7/22/1993 630 W Bonita Ave.

Chevron #9-1099 Soil Gasoline Completed -
Closed 9/29/1995 111 W Bonita Ave.

City of San Dimas Soil Aviation Completed -
Closed 4/10/1997 245 E Bonita Ave.

Texaco (Former) Soil Gasoline Completed -
Closed 11/17/2000 304 W Bonita Ave.

Machinery &
Equipment*
None
Specified
Metals/Heavy Metals,
Petroleum/Fuels/Oils
Completed -
Closed 11/2/2001 115 N Cataract Ave.

Shell Service Station Aquifer Gasoline Completed -
Closed 2/23/2011 630 W Bonita Ave.

LA Co. Sheriff San
Dimas Soil Gasoline Completed -
Closed 6/19/2018 122 N San Dimas
Ave.

Gas & Go (Former M&N
Drive-In Dairy)
Under
Investigation Diesel, Gasoline Completed -
Closed 2/8/2019 105 E Arrow Hwy.

EnviroStor
Name Media Contaminants Status Status Date Address
Coopers Plating Co Soil
Lead (tetraethyl lead),
Chromium III, Copper,
Compounds
Completed -
Closed 6/20/1995 304 W Bonita Ave.

Texaco Service Station Soil Lead Completed -
Closed 8/15/1995 304 W Bonita Ave.

As the DTSP is a programmatic, planning-level policy document, the Project would not directly initiate or entitle any new development projects on said sites. While the sites have been determined safe by the relevant regulatory bodies, future development projects on any such site would be subject to site-specific review by the City of San Dimas, potentially including environmental review under the California Environmental Quality Act. Future development projects would be required to analyze any potential impacts resulting from the site’s past uses involving hazardous materials and to implement any mitigation measures deemed necessary to address any potential impacts identified. The Project would result in development projects within the Specific Plan area, and the demolition of existing buildings and ground disturbance for construction. As such, the proposed Project would not be located on a site which is

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-18 Community Development Department Downtown Specific Plan Draft EIR June 2024
included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5.

Therefore, impacts would be less than significant.
e. For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area? Portions of the DTSP planning area lie within the Airport Influence Area (AIA) established in the Brackett Field Airport Land Use Compatibility Plan (ALUCP). Bracket Field Airport, located less than two miles to the southeast of the planning area in La Verne, is a public general aviation airport owned and operated by Los Angeles County.

The portions of the DTSP planning area that lie within the AIA are designated Zone E – Other Airport Environs, which consists of all areas in a two-mile radius of the airport but that lie outside of any other established safety zones. Properties designated Zone E lie beyond the airport’s CNEL 55 dB contour and are subject only to very low noise impacts and are considered to be subject to low risk of near-airport accidents. Buildings in Zone E are limited to 150 feet or more above runway elevation to further reduce risk related to potential near-airport accidents. As the land use regulations that would be established as part of the DTSP would not permit the development of buildings above 150 feet, the Project would not conflict with the provisions of the Brackett Field Airport ALUCP. Therefore, impacts on people residing or working in the project area resulting from airport noise or other safety hazards would be less than significant.
f. Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan?
The Project provides design guidance for roadways, sidewalks, and driveways within the DTSP planning area that would ensure emergency access would be maintained. Further, existing City development standards would require new development within the Specific Plan to be designed so as not to interfere with an adopted emergency response plan or emergency evacuation plan. The potential for roadway impacts during construction is discussed in Section 4.11, Transportation. g. Expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires?
The Downtown Specific Plan area is located within an urban area that does not contain wildlands and is not located in an area classified as a Very High Fire Hazard Severity Zone. The entirety of the Project Area falls within a Local Responsibility Area (LRA). Local Responsibility Areas include incorporated cities, urban regions, agriculture lands, and portions of the desert where the local government is responsible for

4.6 Hazards and Hazardous Materials
City of San Dimas 4.6-19 Community Development Department Downtown Specific Plan Draft EIR June 2024
wildfire protection. This is typically provided by city fire departments, fire protection districts, counties, and by CAL FIRE under contract. As such, no impacts would occur.

Cumulative Impacts
As discussed above, implementation of the Downtown Specific Plan would result in development that has the potential to occur on or adjacent to sites that use or have previously used hazardous materials, which could place construction workers and future residents at-risk. Construction-related hazardous materials impacts would generally be site-specific and limited to the duration of the construction activity, and would continue to be highly regulated under federal, state, and local regulations. Therefore, there would not be a cumulatively considerable contribution to a cumulatively significant impact.

Residential development as part of the cumulative development may be located in proximity or adjacent to facilities that use, store, transport, and dispose hazardous materials, which could increase an individual’s exposure to hazardous materials. The cumulative projects that would use, store, transport, and dispose hazardous materials would also be required to comply with hazardous materials laws, which are designed to avoid and minimize adverse impacts on public health, safety, and the environment. Each cumulative project has been or would be subject to environmental review and if significant impacts are identified, mitigation measures would be implemented to avoid or reduce the impacts. Therefore, the cumulative impact would be less than significant.

4.6.6 MITIGATION
As impacts would be less than significant, no mitigation is necessary.

City of San Dimas 4.7-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.7 LAND USE AND PLANNING

4.7.1 THRESHOLDS OF SIGNIFICANCE
The following thresholds for determining the significance of impacts related to land use and planning are derived from the environmental checklist form contained in Appendix G of the most recent update of the State CEQA Statutes and Guidelines.
a. Physically divide an established community?
b. Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect?

4.7.2 ENVIRONMENTAL SETTING
Existing Conditions
The Project Area consists of portions of the existing downtown area of San Dimas and the surrounding Town Core area. Most properties within the Study Area have been previously developed, with uses including commercial, multi-family, and public facilities. Between the 57 (Orange) freeway and North Eucla Avenue, existing development uses can be characterized as highway-oriented commercial, including a hotel, auto-oriented commercial strips, and several big-box retailers. Between North Eucla Avenue and South Cataract Avenue, there are two vacant properties, a restaurant, a bowling alley, and a small number of professional offices. East of South Cataract Avenue, existing development along Bonita Avenue primarily includes both auto-oriented and street-facing commercial properties, parking lots, and, east of South Walnut Avenue, a small number of multi-family residential properties. A complex of public facilities, including the San Dimas City Hall, the San Dimas Library, Civic Center Park, United States Post Office, Los Angeles County Fire Department Station 64, and the San Dimas Sheriff’s Office are located at the intersection of Bonita and South Walnut Avenues.

The Downtown Specific Plan (DTSP) area is roughly divided from the northwest to the southeast by the Metro “A” Line (formerly known as the “Gold”/”L” Line) right-of-way, which intersects with Bonita Avenue at Cataract Avenue. The San Dimas Station of the Metro “A” Line is situated at San Dimas Avenue, just south of Bonita Avenue. The DTSP area is further bounded to the west by the 57 (Orange) Freeway. The surrounding area includes residential neighborhoods to the north, the remainder of the Bonita Avenue commercial corridor to the east, industrial, office, and multi-family areas to the south and southwest, and big-box retail commercial shopping areas to the west, opposite the Orange Freeway.

4.7 Land Use and Planning
City of San Dimas 4.7-2 Community Development Department Downtown Specific Plan Draft EIR June 2024
Regulatory Framework
City of San Dimas General Plan
California Planning and Zoning Law requires each city to prepare and adopt “a comprehensive, long term general plan for the physical development” of land within its jurisdiction. Under Gov. Code Section 65302, each General Plan must include a land use element that designates the general distribution, location and extent of the uses of the land.

California Government Code Section 65450 states that a city may prepare a specific plan “for the systematic implementation of the general plan…” A Specific Plan must include text and diagrams that specify the distribution, location, and extent of uses of land and infrastructure within the plan area, standards for development, and a program of implementation. California Government Code 65454 states that “No specific plan may be adopted or amended unless the proposed plan or amendment is consistent with the general plan.”
The San Dimas General Plan is the blueprint for future growth and development in the City. The land use element of the General Plan is based on a community vision to establish a pattern for compatible land uses which reflect existing conditions, approved land use, open space areas, and to guide future development. The Plan area is currently designated in the General Plan as a range of commercial, residential, and institutional uses. In addition, the Land Use Element contains the following land use goals:

1. Maintain the rural small-town low-density atmosphere of San Dimas.

2. Preserve the integrity of the foothills, including the northern foothills, Puddingstone Hills, and Way Hill.

3. Ensure that all portions of the City are adequately served with essential services, utilities, and recreational and open space facilities.

4. Plan and create an urban form that effectively utilizes urban infrastructure and services. Plan for orderly growth rather than “leapfrog” development.

5. Provide well planned commercial centers and nodes. Discourage “strip” commercial development.

6. Revitalize and improve downtown as a community focus.

7. Maintain existing mobile homes to meet the need for affordable housing stock for the citizens of San Dimas.

8. Ensure adequate community participation in planning for the future of San Dimas.

9. Enhance a unified and high-quality visual image for the City.

10. Development of the northern foothills area shall maximize preservation of the natural environment, recognize the opportunities and constraints that the land imposes, and accommodate such

4.7 Land Use and Planning
City of San Dimas 4.7-3 Community Development Department Downtown Specific Plan Draft EIR June 2024
development as can be designed to minimize impacts on the natural environment and protect public health and safety.

Connect SoCal
The State of California adopted Senate Bill (SB) 375, the Sustainable Communities and Climate Protection Act of 2008, to outline growth strategies and better integrate regional land use and transportation planning in a way that will help the State meet its GHG reduction mandates. SB 375 requires that the State’s 18 metropolitan planning organizations incorporate a “sustainable communities strategy” within their respective regional transportation plans to achieve their respective region’s GHG emission reduction targets set by CARB. SCAG is the metropolitan planning organization for the region that includes the Project. On September 3, 2020, SCAG adopted the 2020–2045 RTP/SCS: Connect SoCal which includes regional land use goals and growth strategies.

4.7.3 IMPACT ANALYSIS
Project Impacts
a. Physically divide an established community?
Rather than dividing an established community, the Project is intended to encourage greater connections within the DTSP area and between the DTSP area and the surrounding community by fostering a highquality, pedestrian-oriented public realm framed by context-sensitive buildings that enhance the historic character of Downtown San Dimas. The Project will result in compact development near the new Metro “A” Line transit station to decrease automobile dependency, reduce both local and regional traffic congestion and related greenhouse gas emissions, and provide additional guidance and plans to increase multimodal access to and from the historic Downtown area. The DTSP Project Area also includes several opportunity sites within walking distance of the transit station that provide significant potential for infill development and adaptive reuse of existing underutilized downtown properties, the redevelopment of which would support greater pedestrian and multi-modal connectivity in the surrounding area through the enhancement of the public realm.
b. Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? City of San Dimas General Plan
The Project has been designed to further the vision of San Dimas contained in the San Dimas General Plan.

The Project would support mixed-use, transit-oriented development that is consistent with the existing General Plan and includes a high-quality, pedestrian-oriented public realm framed by context-sensitive buildings that emulate the historic character of San Dimas’ Historic Core. The Project represents a model

4.7 Land Use and Planning
City of San Dimas 4.7-4 Community Development Department Downtown Specific Plan Draft EIR June 2024
of sustainable development practices; seeks to support existing residential neighborhoods through providing a vibrant link between the existing downtown area and the surrounding neighborhoods; and accommodates a range of uses. Furthermore, by focusing a portion of the forecasted growth of San Dimas into the Project area, the City’s open space and habitat resources that are at distant locations would experience less development pressure. As such, the Project is supportive of the General Plan Land Use Goals.

The Project would establish land use regulations, zoning, development standards, and design guidelines for the Project area. The Project would include a General Plan Amendment and amendments to the municipal code to establish consistency between the Project and the General Plan. As stated in Government Code section 65450, the intent of a specific plan is to implement the General Plan in a specified geographic area and California Government Code Section 65454 requires that all specific plans be consistent with the general plan. As such, the Project would not conflict with the land use plans and policies of the City and impacts would be less than significant.

Connect SoCal
Table 4.7-1: Connect SoCal Consistency, provides an assessment of the Project’s relationship to regional goals pertaining to issues of environmental concern contained in various chapters of the SCAG 2020-2045 RTP/SCS. The analysis contained in Table 4.7-1 concludes that the Project would not conflict with the land use goals of Connect SoCal. In addition, SCAG has identified priority growth areas within which cities are encouraged to focus growth. Downtown San Dimas is one of these priority growth areas due to the presence of transit and neighborhood mobility features. Accordingly, impacts would be less than significant.

Table 4.7-1: Connect SoCal Consistency
Goals and Policies Consistency Analysis
Goal 1: Encourage regional economic prosperity
and global competitiveness
Consistent. This Goal is directed towards actions taken by SCAG and the City and does not apply to the Project.

Nonetheless, the Project would enhance the prosperity of the neighborhood through the creation of up to
approximately 3,600 additional residential units, providing residential opportunities to the community.

Goal 2: Improve mobility, accessibility, reliability,
and travel safety for people and goods.

Consistent. The Project would be consistent with the City of San Dimas General Plan, including its Circulation Element.

The traffic analysis conducted pursuant to CEQA
requirements finds that the Project would have a less than significant impact on the City’s transportation system, and that impacts regarding VMT generation would also be less than significant. The Project thus would not conflict with

4.7 Land Use and Planning
City of San Dimas 4.7-5 Community Development Department Downtown Specific Plan Draft EIR June 2024
Table 4.7-1: Connect SoCal Consistency
Goals and Policies Consistency Analysis
efforts to improve mobility, accessibility, reliability, and travel safety for people and goods.

Goal 3: Enhance the preservation, security, and
resilience of the regional transportation system.

Consistent. While not necessarily applicable to an individual development project, the Project would support this goal by improving the viability of alternative forms of
transportation in the area immediately surrounding the
Project site. The Project includes the development of a transit-oriented, mixed-use downtown area designed to
provide better connections to sidewalks, bicycle
infrastructure, and the new Metro “A” Line under
construction in the City.

Goal 4: Increase person and goods movement and
travel choices within the transportation system.

Consistent. While not necessarily applicable to an individual development project, the Project would support this goal by improving local access to alternative forms of
transportation, including walking, biking, and transit, with appropriate design considerations to account for future population growth and multi-modal choices.

Goal 5: Reduce greenhouse gas emissions and
improve air quality.

Consistent. The Project involves the development of a
multi-modal, mixed-use downtown core area that would
facilitate walking, biking, and transit access for residents, businesses, and visitors to the Project area. The Project’s provisions for safe and convenient walking, biking, and the use of improved transit facilities to reach social, recreation, and employment opportunities supports the goal of
reducing GHG emissions and improving air quality through promoting the use of these alternative modes among
residents of the community.

Goal 6: Support healthy and equitable
communities.

Consistent. The Project would support healthy, active
lifestyles among residents through the creation of a new transit-oriented, mixed-use downtown district that
supports walking, bicycling, and transit use to reach
employment and recreational opportunities.

Goal 7: Adapt to a changing climate and support an
integrated regional development pattern and
transportation network.

Consistent. This policy is directed towards SCAG actions to support integrated regional development patterns.

However, the Project would result in infill development that is integrated with the existing transportation network, and thus would support this goal. The Project would further be consistent with the City of San Dimas General Plan,
supporting the City’s overall vision for regional
development.

Goal 8: Leverage new transportation technologies
and data-driven solutions that result in more
efficient travel.

Not Applicable. This policy is directed towards SCAG actions to leverage the use of new transportation technologies
using data-driven solutions.

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Table 4.7-1: Connect SoCal Consistency
Goals and Policies Consistency Analysis
Goal 9: Encourage development of diverse housing
types in areas that are supported by multiple
transportation options.

Consistent. The Project would result in the development of new multi-family housing consisting of apartments,
townhomes and condominiums in the City’s downtown,
which would increase the range of housing types available in the vicinity. As the Project is designed to complement the development of the new San Dimas Metro “A” Line station, all such new housing would be well-supported by transit infrastructure, and the DTSP’s pedestrian-oriented design considerations would result in a walkable area that
promotes active transportation among residents and
visitors.

Goal 10: Promote conservation of natural and
agricultural lands and restoration of habitats.

Consistent. The Project is located in the highly-urbanized downtown area of the City and would promote higherdensity development in this area to maximize the utility of existing and planned infrastructure. As discussed in this EIR, focusing new development in the central area of the City would reduce development pressures on outlying areas,
including hillside and environmentally sensitive areas.

Source: SCAG, Connect SoCal, 2020–2045 RTP/SCS, September 2020.

Cumulative Impact
The Project is centered on the San Dimas’ existing Town Core and downtown areas, and is surrounded by residential neighborhoods, highway-oriented commercial uses, and the site of the future Metro “A” Line station. Development following the adoption of the Downtown Specific Plan would knit these areas together. The maximum Floor Area Ratio (FAR) for the planning area would range from 1.5 to 2.0, which is the same as other nearby mixed-use districts, and the development standards of the Project would create a transitional scale at the interface with adjacent residential neighborhoods. As stated above, the intent of the Project is to implement the principles of the City’s General Plan over a specified geographic area.

As such, the Project would not have a considerable contribution to a cumulative impact.

4.7.4 MITIGATION
As impacts would be less than significant, no mitigation is necessary.

City of San Dimas 4.8-1 Community Development Department Downtown Specific Plan Draft EIR June 2024

4.8 NOISE

4.8.1 THRESHOLDS OF SIGNIFICANCE
The following thresholds for determining the significance of impacts related to noise are derived from the environmental checklist form contained in Appendix G of the most recent update of the State CEQA Statutes and Guidelines.
a. Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies?
b. Generation of excessive groundborne vibration or groundborne noise levels? c. For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels?

4.8.2 ENVIRONMENTAL SETTING
Fundamentals of Noise
Sound is mechanical energy transmitted by pressure waves in a compressible medium such as air. Noise is generally defined as unwanted sound. Sound is characterized by various parameters that describe the physical properties of sound waves. These properties include the rate of oscillation (frequency); the distance between successive high and low noise levels, the speed of propagation; and the pressure level or energy content of a given sound wave. In particular, the sound pressure level has become the most common descriptor used to characterize the loudness of an ambient sound level.

The unit of sound pressure expressed as a ratio to the faintest sound detectable to a person with normal hearing is called a decibel (dB). Sound or noise can vary in intensity by more than one million times within the range of human hearing. A logarithmic loudness scale, similar to the Richter scale for earthquake magnitude, is used to describe sound-intensity levels. The human ear is not equally sensitive to all sound frequencies within the entire spectrum. Noise levels at maximum human sensitivity are factored more heavily into sound descriptions in a process called A weighting, written as dBA. Further reference to decibels in this analysis should be understood to be A-weighted.

Several noise descriptors have been developed to evaluate the adverse effect of community noise on people. Since noise level fluctuates over time, an equivalent sound level (Leq) descriptor is used to describe typical time-varying instantaneous noise. Finally, because community receptors are more sensitive to unwanted noise intrusion during evening and nighttime hours, State law requires that an

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artificial decibel increment be added to noise occurring during those time periods. The 24-hour noise descriptor with a specified evening (7:00 PM to 10:00 PM) and nighttime (10:00 PM to 7:00 AM) penalty is called the Community Noise Equivalent Level (CNEL).

Noise sources can generally be categorized as one of two types: (1) point sources, such as stationary mechanical equipment; and (2) line sources, such as a roadway. Sound generated by a point source typically diminishes (attenuates) at a rate of 6 dBA for each doubling of distance from the source to the receptor at acoustically hard sites, and at a rate of 7.5 dBA at acoustically soft sites.1 A hard or reflective site consists of asphalt, concrete, or very hard-packed soil, which does not provide any excess groundeffect attenuation. An acoustically soft or absorptive site is characteristic of normal earth and most ground with vegetation. As an example, a 60-dBA noise level measured at 50 feet from a point source at an acoustically hard site would be 54 dBA at 100 feet from the source and 48 dBA at 200 feet from the source.

Noise from the same point source at an acoustically soft site would be 52.5 dBA at 100 feet and 45 dBA at 200 feet from the source. Sound generated by a line source typically attenuates at a rate of 3 dBA and 4.5 dBA per doubling of distance from the source to the receptor for hard and soft sites, respectively. Table

4.8-1: Noise Descriptors identifies various noise descriptors developed to measure sound levels over different periods of time. Man-made or natural barriers can also attenuate sound levels, as illustrated in Table 4.8-2: Attenuation of Typical Structures.

Noise Terminology
Different types of scales are used to characterize the time-varying nature of sound. Applicable scales include the maximum noise level (Lmax), equivalent noise level (Leq), and the CNEL. Lmax is the maximum noise level measured during a specified period. Leq is the average A-weighted sound level measured over a given time interval. Leq can be measured over any period, but is typically measured for 1-minute, 15- minute, 1-hour, or 24-hour periods. CNEL is an average A-weighted sound level measured over a 24-hour period. However, this noise scale is adjusted to account for some individuals’ increased sensitivity to noise levels during the evening and nighttime hours. A CNEL noise measurement is obtained by adding 5 dBA to sound levels occurring during the evening, from 7:00 PM to 10:00 PM, and 10 dBA to sound levels occurring during the nighttime, from 10:00 PM to 7:00 AM. The 5 dBA and 10 dBA “penalties” are applied to account for increased noise sensitivity during the evening and nighttime hours. Day-night average level (Ldn) is the A-weighted equivalent sound level for a 24-hour period with an additional 10 dB imposed on the equivalent sound levels for nighttime hours of 10:00 PM to 7:00 AM. 1 USDOT FHWA, Fundamentals and Abatement, 97.

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Table 4.8-1: Noise Descriptors
Term Definition
Sound
A disturbance created by a vibrating object, which, when transmitted by pressure waves through a medium such as air, is capable of being detected by a receiving mechanism, such as the human ear or a microphone.

Noise Sound that is loud, unpleasant, unexpected, or otherwise undesirable.

Decibel (dB) The unit for measuring the volume of sound equal to 10 times the logarithm (base 10) of the ratio of the pressure of a measure sound to a reference pressure.

A-Weighted Decibel
(dB[A])
A sound measurement scale that adjusts the pressure of individual frequencies according to human sensitivities. The scale accounts for the fact that the region of highest sensitivity for the human ear is between 2,000 and 4,000 cycles per second (hertz).

Equivalent Continuous
Sound Level (Leq)
The sound level containing the same total energy as a time varying signal over a given time period. Leq is the value that expresses the time averaged total energy of a fluctuating sound level. Leq can be measured over any time period, but is typically measured for 1-minute, 15-minute, 1-hour, or 24-hour periods.

Day-Night Level (Ldn) The energy average of the A-weighted sound levels occurring during a 24-hour period with 10 dBA added sound levels occurring from 10 PM to 7 AM.

Community Noise
Equivalent Level (CNEL)
A rating of community noise exposure to all sources of sound that differentiates between daytime, evening, and nighttime noise exposure. These adjustments add 5 dBA for the evening, 7:00 PM to 10:00 PM, and add 10 dBA for the night, 10:00 PM to 7:00 AM. The 5 and 10 decibel penalties are applied to account for increased noise sensitivity during the evening and nighttime hours. The logarithmic effect of adding these penalties to the 1-hour Leq measurements typically results in a CNEL measurement that is within approximately 3 dBA of the peak-hour Leq.

Sound Pressure level The sound pressure is the force of sound on a surface area perpendicular to the direction of the sound. The sound pressure level is expressed in dB.

Ambient Noise
The level of noise that is all encompassing within a given environment, being usually a composite of sounds from many and varied sources near to and far from the observer. No specific source is identified in the ambient environment.

Note: California Department of Transportation, Technical Noise Supplement; A Technical Supplement to the Traffic Noise Analysis Protocol, (Sacramento, CA: November 2009), N51-N54.

Noise Barrier Attenuation
The introduction of a barrier between a noise source and a sensitive receptor redistributes the sound energy into several paths, including a diffracted path over the top of the barrier, a transmitted path through the barrier, and a reflected path directed away from the sensitive receptor. Diffraction is the bending of sound waves over the top of a barrier. The area behind the barrier in which diffraction occurs is known as a “shadow zone,” and sensitive receptors located in this area will experience some sound attenuation. The amount of attenuation is related to the magnitude of the diffraction angle. The diffraction angle will increase if the barrier height increases or if the distance from sensitive receptors is decreased

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to the barrier. In addition to diffraction with the use of barriers, sound can travel through the barrier itself.

The level of sound transmission through the barrier depends on factors relating to the composition of the barrier (such as its weight and stiffness), the angle of incidence of the sound, and the frequency spectrum of the sound. The rating of a material’s ability to transmit noise is called transmission loss. Transmission loss is related to the ratio of the incident noise energy to the transmitted noise energy, and it is normally expressed in decibels, which represents the amount noise levels will be reduced when the sound waves pass through the material of the barrier. Noise energy can also be reflected by a barrier wall. Thus, the reflected sound energy would not affect the sensitive receptor but may affect sensitive receptors to the left and right of the developed barrier.2 Man-made or natural barriers can also attenuate sound levels; a solid wall or berm may reduce noise levels by 5 to 10 dBA.3 Contemporary wood frame construction techniques in California typically provide about 25 dBA reduction in exterior to interior noise levels. This is due to structural means used to comply with California regulations, such as the Title 24 energy conservation standards. The minimum attenuation of exterior to interior noise provided by typical structures in California is provided in Table 4.8-2: Attenuation of Typical Structures.

Table 4.8-2: Attenuation of Typical Structures
Building Type Open Windows (dBA) Closed Windows (dBA)a
Residences 17.0 25.0
Churches 20.0 30.0
Hospitals/Convalescent homes 17.0 25.0
Offices 17.0 25.0
Theaters 20.0 30.0
Hotels/motels 17.0 25.0
Source: Bolt Beranek and Newman, Inc., Highway Noise: A Design Guide for Highway Engineers, NCHRP Report No. 117, (1971). Prepared for Highway Research Board, National Academy of Sciences, Washington, D.C. a As shown, structures with closed windows can attenuate exterior noise by a minimum of 25.0 to 30.0 dBA.

Vibration
Vibration consists of waves transmitted through a solid medium. Groundborne vibration propagates from the source through the ground to adjacent buildings by surface waves. A vibration may be a single pulse, a series of pulses, or a continuous oscillatory motion. The frequency of a vibrating object describes how 2 U.S. Department of Housing and Urban Development, Office of Community Planning and Development, The Noise Guidebook (n.d.), 21–23.
3 Federal Highway Administration, Highway Noise Fundamentals (1980), 18.

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rapidly it is oscillating, measured in hertz (Hz). Most environmental vibrations consist of a composite, or “spectrum,” of many frequencies, and are generally classified as broadband or random vibrations. The normal frequency range of most groundborne vibrations that can be felt starts from a low frequency of less than 1 Hz to a high of about 200 Hz. Vibration is often measured in terms of the peak particle velocity (PPV) in inches per second (in/sec) because it is related to the stresses that are experienced by buildings.

Vibration is also measured in vibration decibels (VdB). The human threshold of perception is approximately 65 VdB. A vibration velocity of 75 VdB is the approximate dividing line between barely perceptible and distinctly perceptible levels for many people. Vibration levels are acceptable at approximately 85 VdB if there are an infrequent number of events per day.4
Vibration energy attenuates as it travels through the ground, causing the vibration amplitude to decrease with distance away from the source.5 High frequency vibrations reduce much more rapidly than low frequencies, so that in the far-field from a source, the low frequencies tend to dominate. Soil properties also affect the propagation of vibration. When groundborne vibration interacts with a building, there is usually a ground-to-foundation coupling loss, but the vibration can also be amplified by the structural resonances of the walls and floors.6 Vibration in buildings is typically perceived as rattling of windows or of items on shelves, or the motion of building surfaces.

Groundborne vibration is generally limited to areas within a few hundred feet of certain types of construction activities, especially pile driving. Road vehicles rarely create enough groundborne vibration to be perceptible to humans unless the road surface is poorly maintained and there are potholes or bumps.7 If traffic, typically heavy trucks, induces perceptible vibration in buildings, such as window rattling or shaking of small loose items, then it is most likely an effect of low-frequency airborne noise or ground characteristics. Human annoyance by vibration is related to the vibration energy and the number and duration of events, as well as the setting in which the person experiences the vibration. As discussed previously, vibration can be amplified by the structural resonances of the walls and floors of buildings. The more the events or the greater the duration, the more annoying it will be to humans.

Existing Conditions
The proposed DTSP Area includes approximately 202 acres including existing commercial, residential and institutional uses. The DTSP Area includes highway-oriented commercial uses, including a hotel, autooriented commercial strips, and several big-box retailers between the 57 freeway and North Eucla Avenue.

Between North Eucla Avenue and South Cataract Avenue, there are two vacant properties, a restaurant, a 4 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, September 2018), 7-8. 5 California Department of Transportation, Earthborne Vibrations (1990), VII-27. 6 Federal Transit Administration, Transit Noise and Vibration Impact Assessment Manual, September 2018, 7-1, 7-2. 7 Federal Transit Administration (2018), 7-9.

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bowling alley, and a small number of professional offices. East of South Cataract Avenue, existing development along Bonita Avenue primarily includes both auto-oriented and street-facing commercial properties, parking lots, and, east of South Walnut Avenue, a small number of multi-family residential properties. A complex of public facilities, including the San Dimas City Hall, the San Dimas Library, and Civic Center Park, is located at the corner of Bonita and South Walnut Avenues.

Existing Noise Levels
The City of San Dimas General Plan Noise Element identifies the main sources of noise within the City as noise from roadway traffic, noise from train movements on the rail lines, as well as some noise from leaf blowers, special events, and heavy industrial land uses.8 The Noise Element identifies goals, objectives, and policies to avoid noise impacts.

There are two existing rail lines in San Dimas, one located south of Arrow Highway, approximately 0.1 mile south of the DTSP area, and one, previously used as the AT & SF rail line, bisects the DTSP area and goes from the northwest corner of the DTSP area through to the southeast corner. These rail lines are being incorporated into the the Foothill Gold Line light rail line project, which is currently scheduled for completion in January 2025.

The former AT & SF rail line rail line located in the proposed DTSP Area had seventeen operations per day and was identified as a significant source of noise in the General Plan Noise Element.9 The noise levels at these residences near this rail line ranged from 70 to 72 dB Ldn. Measures to mitigate noise from operations on this rail line in the EIR prepared for the Foothill Gold Line Extension Project include noise barriers, building sound insulations, and modifications to warning devices and operations to reduce these impacts to a less than significant level.10 Additional mitigation measures for temporary construction impacts were identified in the 2011 Supplemental EIR for the Foothill Gold Line Extension Project including limiting construction hours, using specified equipment, and temporary noise barriers.11 In the 2012 Final 8 City of San Dimas, General Plan, Noise Element (1991), https://files.sandimasca.gov/Document_Center/Department/Community%20development/Planning%20division/General% 20plan/General%20Plan%20Sections/general-plan-noise-element.pdf. Accessed July 2023. 9 City of San Dimas, General Plan, Noise Element (1991), https://files.sandimasca.gov/Document_Center/Department/Community%20development/Planning%20division/General% 20plan/General%20Plan%20Sections/general-plan-noise-element.pdf. Accessed July 2023. 10 Los Angeles and San Bernardino Counties, Gold Line Foothill Extension Pasadena to Montclair Final Environmental Impact Report (2007), Noise and Vibration, https://foothillgoldline.org/default/final-environmental-impact-report-completed2007/. Accessed August 2023. 11 Los Angeles and San Bernardino Counties, Metro Gold Line Foothill Extension Final Supplemental Environmental Impact Report (2011), https://foothillgoldline.org/default/2010-draft-supplemental-environmental-impact-report/. Accessed August 2023.

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supplemental Impact report, noise and vibration impacts from the Foothill Gold Line Extension project were determined to be less than significant with mitigation.12 Ambient noise measurements were taken at 14 locations within and surrounding the DTSP area, as shown in Figure 4.8-1: Noise Measurement Locations, on February 7, 2023, during daytime hours to determine the existing noise environment. Results are shown in Table 4.8-3: Ambient Noise Measurements.

The ambient noise measurements ranged from 48.9 dBA at Site 14, located along the west end of E. Hera Street, in a residential neighborhood adjacent to Public/Semi-Public land uses, to 83.7 dBA at Site 7, on the northeast corner of S. Cataract Avenue and W. Bonita Avenue, between residential and commercial uses. Existing noise levels exceeded the standards identified in Table 4.8-7: San Dimas Exterior Noise Limits at 9 of the 14 locations. The locations where noise levels were exceeded the City’s noise standards were located close to busy roadways, the 57 freeway and Bonita Avenue, as well as near industrial areas.

The sites where noise levels did not exceed exterior limits were located closer to residential areas as shown in Figure 4.8-1.

Table 4.8-3
Ambient Noise Measurements
Location
Number Description Nearest Use(s) Time Period dBA
1 North of Arrow Highway, west of 57 Freeway, south
of train tracks
Commercial
7:00 AM – 7:15 AM 57.1
1:18 PM – 1:33 PM 59.1
2 North of Arrow Highway
and west of 57 Freeway Commercial
7:19 AM – 7:34 AM 68.4
1:00 PM – 1:15 PM 70.4
3 South of Arrow Highway
and north of W. Cienega
Avenue
Commercial
7:42 AM – 7:57 AM 67.4
1:39 PM – 1:54 PM 68.1
4 Southwest corner of W.

Bonita Avenue and S. Eucla
Avenue
Commercial
8:02 AM – 8:17 AM 57.6
2:00 PM – 2:15 PM 56.2
5 Along S. Acacia Street and
northwest of W. Calora
Street
Residential
8:20 AM – 8:35 AM 53.1
2:18 PM – 1:33 PM 56.8
6 South side of W. Bonita
Avenue and between S. Acacia Street and S. Cataract Avenue Park and
Commercial
8:46 AM – 9:01 AM 63.7
2:37 PM – 1:52 PM 66.0
12 Los Angeles and San Bernardino Counties, Metro Gold Line Foothill Extension Final Supplemental Environmental Impact Report No. 2 (2012), https://foothillgoldline.org/default/2010-draft-supplemental-environmental-impact-report/.

Accessed August 2023.

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Table 4.8-3
Ambient Noise Measurements
Location
Number Description Nearest Use(s) Time Period dBA
7 Northeast corner of S.

Cataract Avenue and W.

Bonita Avenue
Residential and
Commercial
9:04 AM – 9:19 AM 64.0
3:00 PM – 3:15 PM 83.7
8 Southeast corner of S.

Cataract Avenue and W.

Bonita Avenue
Residential
9:21 AM – 9:36 AM 57.5
3:19 PM – 3:34 PM 57.1
9 West of southwest corner
of W. Bonita Avenue and N.

San Dimas Avenue
Commercial
9:51 AM – 10:06 AM 68.1
3:47 PM – 4:02 PM 63.6
10 West of E. Bonita Avenue
and Iglesia Street Commercial
10:13 AM – 10:28 AM 65.1
4:09 PM – 4:24 PM 60.0
11 North of E. Arrow Highway
and west of S. Walnut
Avenue
Industrial
10:33 AM – 10:48 AM 73.9
5:35 PM – 5:50 PM 66.7
12 Northeast corner of E.

Bonita Avenue and S.

Walnut Avenue
Commercial
11:12 AM – 11:27 AM 68.5
4:29 PM –4:44 PM 72.1
13 North of E. Arrow Highway
and east of S. Walnut
Avenue
Industrial
10:53 AM – 11:08 AM 71.9
5:13 PM – 5:28 PM 72.3
14 Along west end of E. Hera
Street Residential
11:33 AM – 11:48 AM 49.8
4:51 PM – 5:06 PM 54.7
Source: Refer to Appendix D for Noise monitoring data sheets.

Notes: dBA = A-weighted decibel; Leq = average equivalent sound level.

Existing Vibration Conditions
As mentioned above existing uses include commercial, multi-family, and public facilities. Based on these uses, the primary source of existing ground-borne vibration within the DTSP area is vehicle traffic on local roadways and trains. According to the FTA,13 typical road traffic-induced vibration levels are unlikely to be perceptible by people. In part, FTA indicates that “it is unusual for vibration from traffic including buses and trucks to be perceptible, even in a location close to major roadways.” Therefore, based on FTA published vibration data, the existing ground vibration environment in the Project vicinity would be below the perceptible levels. Trucks and buses typically generate vibration velocity levels of approximately 63 VdB (at 50-feet distance), and these levels could reach 72 VdB when trucks and buses pass over bumps in the road.
13 Federal Transit Administration, Transit Noise and Vibration Impact Assessment (2018).

Noise Measurement Locations
FIGURE 4.8-1
393-001-23
SOURCE: Google Earth - 2023

APPROXIMATE SCALE IN FEET
0 500 1000 2000
N
Legend:

Project Site
Noise Location Site #

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The FTA also states that vibration from trains is strongly dependent on factors such as how smooth the wheels and rails are as well as other features of the train and the tracks.14 The Metro “A” (formerly “Gold”/”L”) Line Foothill Extension Final EIR identified the potential for high vibration levels in the City of San Dimas for residences located within 50 feet of this planned light rail line.15 Regulatory Framework
Federal
Department of Housing and Urban Development
The US Department of Housing and Urban Development (HUD) has set a goal of 65 dBA CNEL as a desirable maximum exterior standard for residential uses developed under HUD funding. While HUD does not specify acceptable interior noise levels, standard construction of residential uses constructed under Title 24 standards typically provides in excess of 20 dBA of attenuation with the windows closed. Based on this premise, the interior CNEL should not exceed 45 dBA CNEL.16 Federal Transit Administration
The FTA has published a technical manual, Transit Noise and Vibration Impacts Assessment, which provides ground-borne vibration impact criteria with respect to building damage during construction activities.17 According to the FTA guidelines, a vibration criterion of 0.20 PPV should be considered as the significant impact level for nonengineered timber and masonry buildings. Structures or buildings constructed of reinforced concrete, steel, or timber have a vibration damage criterion of 0.50 PPV based on the FTA guidelines. Structures amplify ground-borne vibration, and wood-frame buildings, such as typical residential structures, are more affected by ground vibration than are heavier buildings. The level at which ground-borne vibration is strong enough to cause architectural damage has not been determined conclusively.

The most conservative estimates are reflected in the FTA standards, shown in Table 4.8-4: Construction Vibration Damage Criteria. The FTA has also adopted standards for ground-borne vibration impacts related to human annoyance, as shown in Table 4.8-5: Ground-borne Vibration Sensitivity Criteria. These 14 Federal Transit Administration, Transit Noise and Vibration Impact Assessment (2018). 15 The Construction Authority, “Metro Gold Line foothill Extension From Azusa to Montclair Project” (2013), https://foothillgoldline.org/environmental-reviews/. Accessed August 2023. 16 Code of Federal Regulations, Title 24, sec. 51, Housing and Urban Development, Environmental Criteria and Standards (revised April 1, 2004).
17 US Department of Transportation, Federal Transit Administration (USDOT, FTA), Transit Noise and Vibration Impact Assessment, FTA report no. 0123 (September 2018), accessed May 2020, https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/research-innovation/118131/transit-noise-and-vibration-impactassessment-manual-fta-report-no-0123_0.pdf.

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criteria are based on extensive research that suggests humans are sensitive to vibration velocities in the range of 8 to 80 Hz.18
Table 4.8-4
Construction Vibration Damage Criteria
Building Category PPV (ips) Lv (VdB)
I. Reinforced concrete, steel, or timber (no plaster) 0.5 102 II. Engineered concrete and masonry (no plaster) 0.3 98 III. Nonengineered timber and masonry buildings 0.2 94
IV. Buildings extremely susceptible to vibration damage 0.12 90

Source: Federal Transit Administration Transit Noise and Vibration Impact Assessment Manual, September 2018).

Note: For Max Lv (VdB), Lv = the velocity level in decibels as measured in 1/3 octave bands of frequency over the frequency ranges of 8 to 80 Hz; VdB = vibration decibels; Hz = hertz; ips = inches per second.

Table 4.8-5
Ground-borne Vibration Sensitivity Criteria
Building Category Frequent
Events
Occasional
Events
Infrequent
Events
Category 1: High Sensitivity. Buildings where vibration would interfere with interior operations (e.g., vibration-sensitive research and manufacturing facilities, hospitals with vibration-sensitive equipment, and research operations).
65 VdB1 65 VdB1 65 VdB1
Category 2: Residences and buildings where people normally sleep. 72 VdB 75 VdB 80 VdB Category 3: Institutional land uses, such as schools, churches, other institutions, and quiet offices that do not have vibration-sensitive equipment, but still have the potential for activity interference. 75 VdB 78 VdB 83 VdB
Source: Federal Transit Administration Transit Noise and Vibration Impact Assessment Manual, September 2018.

Note:
1 This criterion limit is based on levels that are acceptable for most moderately sensitive equipment such as optical microscopes. For equipment that is more sensitive, a Detailed Vibration Analysis must be performed.

State
Noise Standards
The California Department of Health Services (DHS) has established guidelines for evaluating the compatibility of various land uses as a function of community noise exposure; these guidelines have been included in the State of California General Plan Guidelines, which is published and updated by the 18 USDOT, FTA, Transit Noise and Vibration Impact Assessment.

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Governor’s Office of Planning and Research.19 According to the State, an exterior noise environment up to 60 dBA CNEL and 65 dBA CNEL is “normally acceptable” for single- and multifamily residential uses, respectively, without special noise insulation requirements. In addition, noise levels up to 75 dBA CNEL are “conditionally acceptable” with special noise insulation requirements, while noise levels at 75 dBA CNEL and above are “clearly unacceptable” for residential uses. In addition, Section 65302(f) of the California Government Code requires each county and city in the State to prepare and adopt a comprehensive long-range general plan for its physical development, with Section 65302(g) requiring a noise element to be included in the general plan. The noise element must (1) identify and appraise noise problems in the community, (2) recognize Office of Noise Control guidelines, and (3) analyze and quantify current and projected noise levels.

DHS’s Office of Noise Control has established guidelines to provide communities with noise environments that it deems to be generally acceptable based on land-use categories. These guidelines serve as a primary tool for a city to use to assess the compatibility between land uses and outdoor noise. Noise exposure for single-family uses is normally acceptable when the CNEL at exterior residential locations is equal to or below 60 dBA, conditionally acceptable when the CNEL is between 55 to 70 dBA, and normally unacceptable when the CNEL exceeds 70 dBA. Some overlap exists between categories. These guidelines apply to noise sources such as vehicular traffic, aircraft, and rail movements.

Vibration Standards
The California Department of Transportation (Caltrans) published its Transportation and Construction Vibration Guidance Manual in April 2020.20 The manual provides practical guidance to Caltrans engineers, planners, and consultants who must address vibration issues associated with the construction, operation, and maintenance of Caltrans projects. This manual provides guidelines for assessing vibration damage potential to various types of buildings, ranging from 0.08 to 0.12 inches per second for extremely fragile historic buildings, ruins, and ancient monuments, to 0.50 to 2.0 inches per second for modern industrial and commercial buildings.

The guidance and procedures provided in the Caltrans manual should be treated as screening tools for assessing the potential for adverse effects related to human perception and structural damage. General information on the potential effects of vibration on vibration-sensitive research and advanced-technology facilities is also provided, but a discussion of detailed assessment methods in this area is beyond the 19 State of California, Governor’s Office of Planning and Research, General Plan Guidelines 2017, 374, accessed July 2023, http://opr.ca.gov/planning/general-plan/guidelines.html. 20 California Department of Transportation (Caltrans), Transportation and Construction Vibration Guidance Manual, April 2020, accessed July 2023, https://dot.ca.gov/-/media/dot-media/programs/environmentalanalysis/documents/env/tcvgm-apr2020-a11y.pdf.

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manual’s scope. The document is not an official policy, standard, specification, or regulation. Therefore, the vibration analysis in this Draft EIR is based on the FTA’s standards and the Caltrans standards are included for informational purposes only.

State of California Building Code
California’s noise insulation standards are codified in the California Code of Regulations, Title 24, Building Standards Administrative Code, Part 2, California Building Code. These noise standards are applied to new construction in California for the purpose of interior noise compatibility from exterior noise sources. The regulations specify that acoustical studies must be prepared when noise-sensitive structures, such as residential buildings, schools, or hospitals, are located near major transportation noise sources, and where such noise sources create an exterior noise level of 60 dBA CNEL or higher. Acoustical studies that accompany building plans must demonstrate that the structure has been designed to limit interior noise in habitable rooms to acceptable noise levels. For new residential buildings, schools, and hospitals, the acceptable interior noise limit for new construction is 45 dBA CNEL.

California Noise Insulation Standards
The California Noise Insulation Standards21 require that interior noise levels from exterior sources be 45 dBA or less in any habitable room of a multi-residential use facility (e.g., hotels, motels, dormitories, longterm care facilities, and apartment houses, except detached single-family dwellings) with doors and windows closed. Measurements are based on CNEL or Ldn (the day–night average): whichever is consistent with the noise element of the local general plan. Where exterior noise levels exceed 60 dBA CNEL, an acoustical analysis for new development may be required to show that the proposed construction will reduce interior noise levels to 45 dBA CNEL. If the interior 45 dBA CNEL limit can be achieved only with the windows closed, the residence must include mechanical ventilation that meets applicable Uniform Building Code (UBC) requirements.

California Department of Health Services
The State of California Department of Health Services, Environmental Health Division, has published recommended guidelines for noise and land use compatibility, referred to as the State Land Use Compatibility Guidelines for Noise (State Noise Guidelines). The State Noise Guidelines, illustrated in Figure 4.3-6: Land Use Compatibility to Noise indicates that residential land uses and other noise-sensitive receptors generally should locate in areas where outdoor ambient noise levels do not exceed 65 to 70 dBA CNEL. According to the State Noise Guidelines, an exterior noise level of 60 dBA CNEL is considered to be “normally acceptable” for single-family, duplex, and mobile homes involving normal, conventional 21 California Code of Regulation, Title 24, sec. 3501 et seq.

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City of San Dimas 4.8-14 Community Development Department Downtown Specific Plan Draft EIR June 2024
construction, without any special noise insulation requirements. Exterior noise levels up to 65 dBA CNEL are typically considered “normally acceptable” for multifamily units and transient lodging without any special noise insulation requirements. Between these values and 70 dBA CNEL, exterior noise levels are typically considered “conditionally acceptable,” and residential construction should only occur after a detailed analysis of the noise reduction requirements and needed noise attenuation features have been included in the Project design. Exterior noise attenuation features include, but are not limited to, setbacks to place structures outside the conditionally acceptable noise contour, orienting structures so no windows open to the noise source, and/or installing noise barriers such as berms and/or solid walls.

Local
City of San Dimas General Plan Noise Element
The City of San Dimas General Plan Noise Element has established noise/land use compatibility guidelines used as a planning tool to establish criteria for the acceptable total noise levels to which land uses are exposed.22 Table 4.8-6 San Dimas Land Use Compatibility for Community Noise Exposure displays these guidelines, which are based on CNEL. As shown in Table 4.8-6, acceptable noise levels increase as the sensitivity of the land use decreases. Once land uses are established, noise levels are regulated through the City’s noise ordinance, which establishes hourly noise level limits and enforcements procedures to restrict noise from individual noise generators.

Additionally, the General Plan Noise Element identifies the impact of construction noise that occurs during the daytime to be minimal for no more than two or three months of activity. 22 City of San Dimas, General Plan, Noise Element (1991), https://files.sandimasca.gov/Document_Center/Department/Community%20development/Planning%20division/General% 20plan/General%20Plan%20Sections/general-plan-noise-element.pdf. Accessed July 2023.

Table 4.8-6
San Dimas Land Use Compatibility for Community Noise Exposure Land Use Categories Community Noise Equivalent Level (CNEL) 55 60 65 70 75 80 85
Residential—Low-Density Single-Family,
Duplex, Mobile Homes
Residential—Multi Family
Transient Lodging - Motel, Hotels

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City of San Dimas Municipal Code
The City’s Noise Ordinance minimizes noise conflicts between neighboring properties through enforcement of applicable regulations. Section 8.36.040 of the San Dimas Municipal Code23 established noise regulations within the City. The Municipal Code establishes interior and exterior noise limits for residential areas within the City which are outlined below in Table 4.8-7: San Dimas Exterior Noise Limits. 23 San Dimas Municipal Code, Title 8, Ch. 8.36, Sec. 8.36.040.

Table 4.8-6
San Dimas Land Use Compatibility for Community Noise Exposure Land Use Categories Community Noise Equivalent Level (CNEL) 55 60 65 70 75 80 85
Schools, Libraries, Churches, Hospitals,
Nursing Homes
Auditoriums, Concert Halls, Amphitheaters
Sports Arena, Outdoor Spectator Sports
Playgrounds, Neighborhood Parks
Golf Courses, Riding Stables, Water
Recreation, Cemeteries
Office Buildings, Businesses, Commercial,
and Professional
Industrial, Manufacturing, Utilities,
Agriculture
Normally Acceptable: Specified land use satisfactory based upon the assumption that any buildings are conventionally constructed with no special noise installation requirements.

Conditionally Acceptable: New construction or development undertaken only after detailed analysis of the noise reduction requirements is made and necessary noise insultation featured are included in design. Conventional construction, but with closed windows and fresh air supply system or air conditioning with normally suffice. Outdoor environment will seem noisy.

Normally Unacceptable: New construction or development generally discouraged, but if it does proceed, a detailed analysis of noise reduction requirements must be made with needed noise insulation features included in design and outdoor areas must be shielded.

Clearly Unacceptable: New construction or development should generally not be undertaken. Construction cost to make indoor environmental acceptable would be prohibitive and outdoor environment would not be usable.

Source: City of San Dimas, General Plan, Noise Element (1991), https://files.sandimasca.gov/Document_Center/Department/Community%20development/Planning%20division/General %20plan/General%20Plan%20Sections/general-plan-noise-element.pdf. Accessed July 2023.

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City of San Dimas 4.8-16 Community Development Department Downtown Specific Plan Draft EIR June 2024
Additionally, Section 8.36.100 prohibits construction work that is within a residential zone or 500 feet from a residential zone to occur during the hours 8:00 PM to 7:00 AM, on Sundays, or on any public holiday.24 Section 8.36 of the Municipal Code cites the dangers of noise at certain levels and potential detriments to health, safety, welfare, and quality of life. Pursuant to the City Noise Ordinance, the City restricts noise generated at a property from exceeding certain noise levels for extended periods of time to protect people from objectionable non-transportation noise sources. However, the City does not set specific noise limits for construction activities.

Table 4.8-7
San Dimas Exterior Noise Limits
Land Use Time Periods Noise Level Standard (dBA)
Residential, Low and Medium Density
7:00 AM − 6:00 PM 50
6:00 PM − 10:00 PM 45
10:00 PM − 7:00 AM 40
Residential, High Density
7:00 AM − 6:00 PM 60
6:00 PM − 10:00 PM 55
10:00 PM − 7:00 AM 50
Commercial
7:00 AM − 6:00 PM 60
6:00 PM − 10:00 PM 55
10:00 PM − 7:00 AM 50
Industrial
7:00 AM − 6:00 PM 70
6:00 PM − 10:00 PM 60
10:00 PM − 7:00 AM 55

Source: San Dimas Municipal Code, Section 8.36.040

4.8.3 IMPACT ANALYSIS
a. Generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies?
Potential noise and vibration impacts associated include short-term construction and long-term operational (stationary source and mobile vehicular) noise. Short-term impacts are usually associated with noise and vibration generated by construction activities. Long-term impacts include effects on both surrounding land uses as well as noise-sensitive on-site uses, which can include stationary and traffic operations. For the purposes of this analysis, it is expected that the long-term operational noise impacts associated with the proposed Project would be a product of increased off- site traffic noise impacts and 24 San Dimas Municipal Code, Title 8, Ch. 8.36, Sec. 8.36.100.

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from on-site stationary noise sources. The evaluation of noise and vibration impacts associated with the proposed Project includes the following:
• Analysis of potential short‐term construction noise and vibration levels at noise‐sensitive uses was evaluated using the City of San Dimas’s Noise Ordinances and the construction vibration building damage and/or human annoyance criteria recommended by the FTA and Caltrans. • Analysis of long‐term potential noise impacts associated with off‐site vehicular traffic was evaluated using guidelines provided by the FHWA and on‐site traffic noise impacts from nearby roads.

Construction
The City’s General Plan and Municipal Code do not establish numeric acceptable source noise levels or noise level increases at potentially affected receivers for construction activities. Section 8.36.100 of the City’s Municipal Code states that it is unlawful for any person within a residential zone, or within a radius of five hundred feet therefrom, to operate equipment or perform any outside construction or repair work on any building, structure or project, or to operate any pile driver, steam shovel, pneumatic hammer, steam or electric hoist or other construction-type equipment or device between the hours of 8:00 PM of one day and 7:00 AM of the next day, at any time on Sunday, or at any time on any public holiday. To evaluate whether the Project will generate a substantial periodic increase in short-term noise levels at offsite sensitive receiver locations, a construction-related noise level threshold is adopted from the Criteria for Recommended Standard: Occupational Noise Exposure prepared by the National Institute for Occupational Safety and Health (NIOSH). A division of the U.S. Department of Health and Human Services, NIOSH identifies a noise level threshold based on the duration of exposure to the source. The constructionrelated noise level threshold starts at 85 dBA for more than eight hours per day, and for every 3 dBA increase, the exposure time is cut in half. This results in noise level thresholds of 88 dBA for more than four hours per day, 92 dBA for more than one hour per day, 96 dBA for more than 30 minutes per day, and up to 100 dBA for more than 15 minutes per day. For the purposes of this analysis, the lowest, more conservative construction noise level threshold of 85 dBA Leq is used as an acceptable threshold for construction noise at the nearby sensitive receiver locations. Since this construction-related noise level threshold represents the energy average of the noise source over a given time period, they are expressed as Leq noise levels. Therefore, the noise level threshold of 85 dBA Leq is used to evaluate the potential Project-related construction noise level impacts at the nearby sensitive receiver locations.

Construction Activities
Certain land uses, such as residences, schools, and hospitals are particularly sensitive to noise and vibration. Sensitive receptors identified in the San Dimas General Plan include residential uses and educational uses. These uses are regarded as sensitive because they are where residents most frequently

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City of San Dimas 4.8-18 Community Development Department Downtown Specific Plan Draft EIR June 2024
engage in activities that are likely to be disturbed by noise, such as reading, studying, sleeping, resting, or engaging in quiet or passive recreation. Commercial and industrial uses are not particularly sensitive to noise or vibration.

Noise levels generated by typical construction equipment are shown in Table 4.8-8: Typical Maximum Noise Levels for Construction Equipment. The construction equipment-reference noise levels are based on measured noise data compiled by the FHWA. These maximum noise levels would occur when equipment is operating under full power conditions. However, equipment used on construction sites typically operate at less than full power. The acoustical usage factor is the percentage of time that each type of construction equipment is anticipated to be in full power operation during a typical construction day. These values are estimates and will vary based on the actual construction process and schedule.

Table 4.8-8
Typical Maximum Noise Levels for Project Construction Equipment Equipment Description Typical Duty Cycle (%) Spec Lmax (dBA)a Actual Lmax (dBA)a Air Compressor 40 80.0 77.7
Backhoe 40 80.0 77.6
Crane 16 85.0 80.6
Dozer 40 85.0 81.7
Forklift 40 85.0 N/A
Generator 50 82.0 80.6
Grader 40 85.0 N/A
Loader 40 80.0 79.1
Paver 50 85.0 77.2
Roller 20 85.0 80.0
Scraper 40 85.0 83.6
Tractor 40 84.0 N/A
Welder 40 73.0 74.0

Source: FHWA Roadway Construction Noise Model (RCNM) version 1.1 Note: N/A = not available.
a Lmax sound levels are measured 50 feet from the source of the equipment.

To characterize construction-period noise levels, the average (hourly Leq) noise level associated with each construction stage was calculated based on the quantity, type, and usage factors for each type of equipment that would be used during each construction stage. These noise levels are typically associated with multiple pieces of equipment operating simultaneously.

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Construction equipment operates at its noisiest levels for certain percentages of time during operation. It is important to note, equipment would operate at different percentages over the course of an hour.25 During a construction day, the highest noise levels would be generated when multiple pieces of construction equipment are operated concurrently.

To characterize construction-period noise levels, the noise level associated with each construction stage was calculated based on the quantity, type, and usage factors for each type of equipment that would be used during each construction stage. These noise levels are typically associated with multiple pieces of equipment operating simultaneously.

Because the DTSP is a planning document and no specific development projects are proposed at this time, noise levels from construction of subsequent individual development projects that could occur cannot be precisely estimated at this time. A general estimate of likely construction noise levels was developed for a scenario in which a reasonable number of pieces of construction equipment was assumed to be operating simultaneously with logistical limitations and with the noise equipment located at the construction area nearest to the affected receptors to present a conservative impact analysis. This is considered a worst-case evaluation because construction of the Project would typically use fewer pieces of equipment simultaneously at any given time and, as such, would likely generate lower noise levels than reported herein.

Forecasts of construction noise levels from on-site construction during each phase of construction were completed and are shown in Table 4.8-9: Construction Maximum Noise Estimates. As shown in Table 4.8- 9, construction noise levels at a distance of 25 feet range from a low of 79.7 dBA during the architectural coating phase to a high of 92.3 dBA during the grading phase.

All subsequent individual development projects within the DTSP Area would be required to comply with the construction hours and days specified in the City’s Municipal Code. Construction noise levels would exceed the City’s exterior noise limits, listed in Table 4.8-7, for Residential Low and Medium, Residential High, Commercial, and Industrial zoned areas. Construction noise impacts would be potentially significant prior to mitigation.

Construction measures would be implemented and enforced by the City of San Dimas during construction activities. These measures include optimal muffler systems for all equipment to a sensitive receptor would reduce construction noise levels by approximately 10 dB or more.26 Additionally, Mitigation Measure MM N-1 would require the preparation of a construction management plan which specifies that all 25 Federal Highway Administration, Traffic Noise Model (2006). 26 FHWA, Special Report—Measurement, Prediction, and Mitigation, updated June 2017, accessed March 2020, https://www.fhwa.dot.gov/Environment/noise/construction_noise/special_report/hcn04.cfm.

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City of San Dimas 4.8-20 Community Development Department Downtown Specific Plan Draft EIR June 2024
construction equipment, fixed or mobile, be equipped with properly operating and maintain mufflers and other State-required noise attenuation devices; require the maximum distance between construction equipment staging areas and occupied residential areas; and require the use of electric air compressors and similar power tools. Limiting the number of noise-generating heavy-duty off-road construction equipment (e.g., backhoes, dozers, excavators, loaders, rollers, etc.) simultaneously used in the DTSP area within close proximity of each other would further reduce construction noise levels by approximately 5 to 10 dBA. Limiting construction equipment to operate simultaneously from 25 feet to 75 feet would reduce construction noise levels by approximately 10 dBA. Temporary abatement techniques include the use of temporary and/or movable shielding for both specific and nonspecific operations. An example of such a barrier utilizes noise curtains in conjunction with trailers to create an easily movable, temporary noise barrier system. Additionally, as the DTSP is a document designed to guide development and does not propose specific development projects, future development would be subject to project specific analysis that would identify any mitigation required.

Table 4.8-9
Construction Maximum Noise Estimates
Construction Phase Max Leq
(25 feet)
Land Use Noise Level
Standard
Maximum Outdoor Noise Increase
over Noise Level Standard without
Mitigation Measures (dBA)
Demolition 90.6 Residential 85 +5.6
Site Preparation 85.1 Residential 85 +0.1
Grading 92.3 Residential 85 +7.3
Building
Construction 89.4 Residential 85 +4.4
Paving 89.1 Residential 85 +4.1
Architectural
Coating 79.7 Residential 85 −
Source: FHWA Roadway Construction Noise Model (RCNM) version 1.1 Refer to Appendix D for Construction noise output sheets.

A noise barrier can achieve a 5 dB noise level reduction when it is tall enough to break the line-of-sight to the receiver. After it breaks the line-of-sight, it can achieve approximately 1.5 dB of additional noise level reduction for each one (1) meter (3.3 feet) of barrier height.27 Therefore, an approximately 15-foot tall construction noise barrier would reduce construction noise levels by a minimum 7 dB. With implementation of MM N-1, construction noise levels would be reduced by a minimum of 27 dB, 27 FHWA, Special Report – Measurement, Prediction, and Mitigation, updated June 2017, accessed July 2023, https://www.fhwa.dot.gov/Environment/noise/construction_noise/special_report/hcn04.cfm

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dependent on the construction activity and height of the temporary noise barrier used. Noise impacts would be reduced to less than significant with mitigation.

Further, because the DTSP is a planning document to guide development, and no specific development projects are proposed at this time. The plan itself does not directly enable or entitle construction or development activities. As such, future projects will be subject to the existing regulations and subsequent analysis as needed for any individual development project proposed within the DTSP Area.

Potential future development allowed by the DTSP could result in construction noise outside the DTSP Area as construction would require worker and vendor truck trips to and from the DTSP area to work on the site and deliver supplies to the site. Potential worker, hauler, and vendor trips were estimated using CalEEMod based on input values using conservative assumptions with appropriate, Project-specific adjustments based on equipment types and expected construction activities (See Appendix B: Air Quality Output Sheets). Trucks traveling to and from the DTSP area would be required to travel along haul routes approved by the City. For a typical development project within the DTSP Area, It was estimated that the construction workforce would consist of 15 worker trips per day and 241 hauling trips per day during demolition; 18 worker trips per day during site preparation; 20 worker trips per day during grading; 3,154 worker trips per day and 645 vendor trips per day during building construction; 15 worker trips per day during paving; and 631 worker trips per day during architectural coating.

Noise associated with construction worker and delivery trips was estimated using the Caltrans FHWA Traffic Noise Model based on the estimated maximum number of worker and truck trips in a day provided by CalEEMod. The 3,799 daily trips (combined 3,154 worker trips and 645 vendor trips per day) would generate noise levels during the daytime of approximately 58.0 dBA, measured at a distance of 75 feet nearby sensitive receptors along the roadway. The hauling trips would generate noise levels ranging from

56.2 to 62.0 dBA, measured at a distance of 75 feet from nearby sensitive receptors, depending on the use of medium or heavy-duty trucks. The noise level increases from worker and vendor related trips would be below the significance exterior threshold of 65 dBA for residential uses and off-site construction related vehicle noise at sensitive receptors would be less than significant.

Operation
Subsequent individual development projects within the DTSP will introduce various stationary noise sources similar to existing conditions based off of current land uses. These sources would include HVAC systems. Sensitive receptors could be potentially affected by the introduction of such equipment. Typically, this type of equipment produces noise levels of approximately 56.0 dBA at 50 feet from the source. As the sound distance doubles at 100 feet from the equipment, sound levels would be 50 dBA, which would be similar to the existing ambient noise levels for this area (refer to Table 4.8-3), which range from a low of