Laguna Hills City Council
February 10, 2026

Appendix D:

Biologist’s Resume

Email: [email protected]
Mobile: 303-818-3632

EDUCATION
B.S., Wildlife Ecology, University
of Wisconsin-Madison, 2004

CERTIFICATIONS
Certified Wildlife Biologist, The
Wildlife Society 2014
Certified Technical Service
Provider (TSP) for Fish and
Wildlife Management Plans,
USDA NRCS 2017
Authorized Desert Tortoise
Biologist – Numerous BOs
Unmanned Aircraft System Pilot
Certification, FAA #4177603

TRAINING
Wetland Delineation Training
Course – The Wetland Institute
(2014)
Southwest Willow Flycatcher
Workshop, 2017
USGS Desert Tortoise Health
Assessment and Tissue
Collection Techniques Training,
2009
Matthew South

PRINCIPAL BIOLOGIST
Matthew South founded South Environmental in 2018. He is a certified wildlife biologist with over 18 years of professional experience providing natural resources consulting services for a wide variety of clients that include residential, commercial, government, utility, infrastructure, research, and non-profit projects. For the last 15 years, Mr. South has been an environmental consultant in southern California acting as a Wildlife Biologist and Geographic Information System (GIS) Analyst. In early 2018 he started South Environmental and has since been supporting clients in Los Angeles, Ventura, Santa Barbara, San Bernardino, and Riverside Counties.

Mr. South’s background in ecology has led to a passion for conservation planning and resources assessments for the purpose of preservation and management. The integration of the latest technologies such as advanced GIS systems, mobile computing, and drone sensing allows him to innovate new data collection, analysis, and collaboration tools for the environmental sciences that produce more accurate data and better-informed resource managers.

EXPERTISE
• Conservation and Management Planning. Mr. South’s has extensive experience preparing mitigation and monitoring plans, habitat conservation plans, and technical biological resources management plans that are compliant with federal, state, and local regulations. Mr.

South is the only active NRCS TSP for Fish and Wildlife Plans Certified in California.
• Biological Resources Assessment. Mr. South has completed dozens of biological resources assessments throughout southern California. • Rare Plants and Arborist Services. Mr. South has surveyed and assessed thousands of native and landscaped trees in southern California. He is a certified arborist with 5-years of tree survey experience working closely with some of the most experienced arborists in California. In addition, he has performed hundreds of hours of rare plant surveys and habitat assessments.
• Wetland & Jurisdictional Delineations. Mr. South has conducted dozens of jurisdictional and wetland delineations per the guidelines and methods from the US Army Corps of Engineers (USACE), California Department of Fish and Wildlife (CDFW), and the state Regional Water Quality Control Boards (RWQCB).
• GIS. Mr. South is an expert at spatial data collection and analysis using ESRI mobile and desktop software products and Trimble hardware.

Matthew South Resume, Page 2

SELECT PROJECT EXPERIENCE
St. Andrews Recreation Center Project, City of Los Angeles Department of Recreation and Parks, California (2023). South Environmental was retained to conduct a Biological Resources Assessment (BRA) and Tree Survey Report for the St. Andrew’s Recreation Center at 8701 S St. Andrew’s Place in the City of Los Angeles, California for development on one parcel (Assessor’s Identification Number [AIN] 6036-009-900) owned by the City of Los Angeles and administered by the Department of Recreation and Parks (RAP). The parcel (study area) is in the Empowerment Congress Southwest Area Neighborhood Council in the southcentral part of the City and within the South Los Angeles Community Plan Area. This report identified sensitive or protected biological resources on the parcel and indicated the regulations governing these resources. The biological resources of the parcel was assessed based on a literature review and a field site survey. The Tree Report included a description of the survey area; methods used to survey the trees involving assessment of tree structure, health, and mapping; and the results of the survey including photographs of each tree.

Bronson Canyon Playground Project, City of Los Angeles Department of Recreation and Parks, California (2023). South Environmental was retained to prepare a BRA, jurisdictional delineation, and rare plant survey for the City of Los Angeles RAP Bronson Canyon Playground Project located at 3200 Canyon Drive in the City of Los Angeles, California, for the proposed construction of a playground and access improvements including a new pedestrian walkway on a parcel owned by the City of Los Angeles in Griffith Park with the Assessor’s Identification Number [AIN] 5583-025-900. The BRA identified and assessed the potential impacts to sensitive or protected biological resources on the project site (development areas and associated work areas), indicated the regulations governing these resources, and discussed recommendations for avoiding or mitigating these impacts. The biological resources of the project site were assessed based on a literature review and a field site survey.

Bell Creek Brush Clearance Project, City of Los Angeles Department of Recreation and Parks, California (2023). South Environmental was retained to prepare an Invasive Plant Treatment and Monitoring Plan (plan) detailing the proposed actions to compensate for the temporary impacts to plant communities from the Bell Creek Brush Clearance Project under a Lake and Streambed Alteration Agreement. The implementation of the plan was consistent with measures included in that agreement, including measure 2.22 regarding invasive species management being conducted to ensure protection of the existing wildlife habitat. Implementation of clearance activities under the plan were designed to reduce the presence of and prevent the spread of nonnative and invasive plant species within the Bell Creek area. The plan outlined monitoring and treatment methods to control the spread of non-native and invasive plant species in the project treatment areas and identified priority species and priority treatment areas to focus efforts and resources toward achieving the final success criteria. The biological resources of the parcel were assessed based on a literature review and a field site survey.

Various Locations, WEAP Trainings and Nesting Bird Surveys, City of Los Angeles Department of Recreation and Parks, California (2023). South Environmental was retained to provide Worker Environmental Awareness and Protection (WEAP) Trainings, field survey, monitoring, and reporting, for several City of Los Angeles RAP locations. South Environmental prepared a contractor education brochure in English and Spanish that provided information on protecting nesting birds and included pictures of sensitive plants and wildlife (particularly bats) occurring within the project areas. South Environmental also conducted environmental awareness training to Department inspectors, contractors, and subcontractors at the project site prior to the start of brush clearance activities. South Environmental also conducted as-needed nesting bird surveys, established buffer zones, and performed biological monitoring in response to the presence of active

Matthew South Resume, Page 3
nests. A brief letter report to RAP was prepared to document field observations, protective measures implemented, and the overall success of the measures.

Sepulveda Basin Prescribed Burn Project, City of Los Angeles Department of Recreation, Los Angeles, California (2022). South Environmental was retained to prepare a burrowing owl survey report for use by the City of Los Angeles RAP for the proposed prescribed burning of approximately 86.49 acres of undeveloped areas on the Sepulveda Basin Apollo XI/Valley Fliers Airfield and adjacent lands. Several active burrowing owl (Athene cunicularia) burrows were identified in October 2021 (survey area) during general surveys conducted to support the project in the early planning phase. This report was prepared according to Appendix C and Appendix D of the 2012 Staff Report on Burrowing Owl Mitigation. The report included a description of the project, biological setting, vegetation communities, survey methodology, and survey results that include burrowing owl behavior observations, and recommendations for project implementation that would avoid impacts to burrowing owls and active burrows.

Various Biology Reports within City of Los Angeles (2019-present). Mr. South has prepared and overseen the preparation of dozens of biological resources assessment reports within the City of Los Angeles. These reports are prepared within the range of the population of mountain lions that is the target of the listing status, in the Santa Monica Mountains, San Gabriel Mountains, Simi Hills, and Verdugo Hills. Numerous other projects have been completed that are not listed. Select Projects include:
• Baseline Road in LaVerne
• Altadena Hills Project
• 16 Beverly Park
• 64 Beverly Park
• 74 Beverly Park
• 79 Beverly Park
• Toyopa Drive
• Mapleton Drive
• Tigertail
• 680 Sarbonne
• 777 Sarbonne
• Stradella Road
• Tower Grove
• Bella Drive
• Chautauqua Boulevard
• Benedict Canyon
• Haslam Terrace
• Summitridge Drive
• Rial Lane
• Outpost Ave
• Pasquera
• Beverly Grove
• Multiple Granito Drive Projects
• Floral and Electra Drive Project
• Hillside
• Magnolia
• Swallow
• Sierra Mar
• Beverly Grove
• Stradella
• Chalon Road
• Moraga
• Brentridge
• Viewcrest
• Old Chimney Road
• Multiple Developments on
Mulholland Highway
• Berkley Hall School Project
• Charmel Lane
• Paseo Miramar Roadway Project
• Posetano-Revello Project
• Palmera
• Shadow Mountain Drive
• Astral Project
• Nofral Road Projects
• San Onofre Drive
• Crescent Drive

Email: [email protected]
Mobile: 714-330-6290

EDUCATION
B.S., Ecology, Evolution, &
Organismal Biology, California
State University, Monterey Bay,
2017
M.S., Conservation and
Restoration Science, University
of California, Irvine, 2022
SKILLS
-Scientific collection and
management of field data
-Technical writing
-Project management and
risk assessment
-Plant and animal
identification through
dichotomous keys, field
guides, and experience
-Statistical analyses through
R Studio

CERTIFICATIONS
-Wilderness First Aid
Certification
Dana Briggs Wyler

BIOLOGIST
Dana Briggs Wyler is a current environmental professional and recent graduate from University of California, Irvine's Masters in Conservation and Restoration Science program. Here, she specialized in project management, restoration design, and field monitoring in areas with sensitive species. She has extensive field data collection and restoration experience in central and southern California learned while in school. While at UCI, she was involved with a project monitoring a fuel modification zone using native plant species to support regional biodiversity, especially Least Bell’s Vireo and California Gnatcatcher. She also participated in a restoration and monitoring program of native grasslands in Irvine aimed to provide data for community resilience to fire. More recently, she worked for Southern California Coastal Water Research Project as a toxicologist where she conducted research and assessments of southern California’s water resources.

EXPERTISE
• Field Data Collection. Dana has extensive experience collecting data in diverse terrestrial and aquatic habitats in both southern and central California.
• Biological Monitoring. Dana has diverse experience identifying wildlife species throughout the Southern California region.
• Plant Identification. Dana is proficient in identifying native, non-native, and invasive plant species throughout southern California, specifically in coastal, wetland, riparian, and chaparral.
• Technical Writing. Dana has prepared numerous biological resource assessments reports for the city of Los Angeles. Reports include detailoriented descriptions of biological resources, surveys for specialstatus species, biological resources maps, and assessments of potential impacts to biological resources from development. • Data Management and Analysis. Dana has significant expertise in statistical analyses as well as producing statistical figures through R Studio. She has extensive experience working with both single data sets as well as large databases.

Dana Briggs Wyler Resume, Page 2

SELECT PROJECT EXPERIENCE
South Environmental, Monitoring Biologist. Ramona Expressway (2023-present). As a Biologist for South Environmental, Dana’s responsibilities were to provide WEAP trainings and biological monitoring for the Ramona Expressway project with First Carbon. Duties included:
• Conduct Worker Environmental Awareness Program (WEAP) training to all onsite construction personnel to describe species of concern and requirements to protect them under the Endangered Species Act and the Western Riverside Multi-Species Habitat Conservation Plan and mitigation measures being implemented on the project site to conserve the species of concern. • Monitoring construction activities for the duration of project activities to ensure that all practicable measures are being employed to avoid incidental disturbance of habitat and species:
o establish environmentally sensitive areas around sensitive biological resources on the project site during the construction phase.
o ensure that vegetation clearance activities limit disturbance to the smallest practical area and that construction personnel and activities do not enter environmentally sensitive areas. o perform daily pre-construction sweeps of work areas prior to initiation of daily construction activities.
o inspect open trenches, pits, and pipes or other materials within which a covered species or other sensitive species may become entrapped or hide within.
o Summarize relevant findings in a letter report that will be prepared at the completion of ground disturbing activities.

Aliso Canyon Emergency Monitoring Project Southern California Gas (2023-present). Dana is the lead monitor for a long-term project that includes the removal of sediment from catch basins where sensitive wetlands and wildlife such as coast range newt occurs. Dana is responsible for overseeing the monitoring effort, daily reports, and overall project compliance.

City of LA Recreation and Parks City Park Brush Clearance Monitoring within Riparian Areas (2023).

Dana was the primary monitor that conducted nesting bird surveys and compliance monitoring at White Point Park where brush clearance is performed annually to meet LA Fire Department requirements. The work was within and near riparian areas and wetland and riparian vegetation and wildlife were the target species. Also, Dana monitored nesting coastal California gnatcatchers at this site and protected the nest during the project.

City of Los Angeles Biological Resources Assessments (2023 – present). Dana conducts site assessments for biological resources, surveys for special-status plants and animals, maps and characterizes plant communities and wetlands/streams, and assesses potential impacts to biological resources from proposed developments. Dana has worked on the following reports:
• 41 Mar Vista Biological Resources Report in the Santa Monica Mountains Local Coastal Program (LCP) • 4801 Knob Hill Drive Biologist’s Statement of Biological Resources • 1746 Mandeville SB9 Statement of Habitat
• 2460 Sunset Plaza SB9 Statement of Habitat
• 21050 San Miguel SB9 Statement of Habitat
• 11496 Orum SB9 Statement of Habitat & California Wildlife Habitat Relationship (CWHR) Assessment

Dana Briggs Wyler Resume, Page 3
• 230 Carolwood Biologist’s Statement of Biological Resources • 2383 Mandeville Canyon Biologist’s Statement of Biological Resources • 4960 Calvin SB9 Statement of Habitat
• 8152 Ellenbogen SB9 Statement of Habitat
• 10826 Tuxford Statement of Habitat
Dana has also conducted the following monitoring projects:
• Ramona Expressway monitoring biologist
• Glenoaks/ SoCal Edison compliance monitoring
• White Point nesting bird survey and monitoring
Southern California Coastal Water Research Project (2021 – 2022). Dana was a laboratory and field assistant for coastal wetlands project. Dana later was promoted to research technician in the toxicology department where she coordinated and implemented a water toxicology experiment that support southern California wetlands and waters.

Appendix E:

Site Plan

JANUARY 28, 2026

CITY OF LAGUNA HILLS, CA
24035 El Toro Road
Laguna Hills, CA 92653
SUBJECT: TOLL BROTHERS TOWNHOME PROJECT TRIP GENERATION AND VEHICLE MILES

TRAVELED (VMT) SCREENING ANALYSIS AND GATE QUEUEING STUDY, CITY OF

LAGUNA HILLS

INTRODUCTION
RK ENGINEERING GROUP, INC. (RK) is pleased to provide this Trip Generation and Vehicle Miles Traveled (VMT) Screening Analysis for the proposed Toll Brothers Laguna Hills Townhome Project (hereinafter referred to as “project”).

The purpose of this study is to utilize the City of Laguna Hills Vehicle Miles Traveled Analysis Guidelines under the California Environmental Quality Act General Plan Development Review Traffic Study Guidelines, August 2021, (hereinafter referred to as “Traffic Study Guidelines”) to determine if the project would cause a significant impact to VMT and level of service (LOS) pursuant to the California Environmental Quality Act (CEQA) and the City of Laguna Hills roadway performance standards, respectively. This analysis utilizes the screening criteria established in the Laguna Hills Traffic Study Guidelines.

This report also reviews the proposed gated entry design to help ensure adequate vehicle queueing and circulation is accommodated.

PROJECT DESCRIPTION
The proposed project site will be constructed on the 2.43-acre parcel at 23161 Mill Creek Drive (APN 588-142-07) in the City of Laguna Hills, Orange County, California (Project Site). The project site is located on the west side of Mill Creek Drive, approximately 0.27 miles south of the Lake Forest Drive, Mill Creek Drive, and Scientific Intersection. The project site is currently developed with a two-story office building, surface parking lot, and associated landscaping and pavement. Exhibit A shows the location map of the proposed project.

The proposed project consists of the demolition of the existing office building and associated surface parking lot and landscaping to construct 36 single-family-attached condominium residential units, parking, roadways, and associated infrastructure at a density of 14.8 dwelling units per acre (du/ac).

Two units will be deed-restricted for very low-income households, while the remaining 34 units are designated as above-moderate income.

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Access to the project is proposed via one (1) full-access gated driveway along Mill Creek Drive.

Exhibit A shows an aerial location map of the project site. Exhibit B shows the project’s proposed site plan.

TRIP GENERATION
Trip generation represents the amount of traffic that is attracted and produced by a development.

Trip generation rates from the latest Institute of Transportation Engineers (ITE) Trip Generation Manual (11th Edition, 2021) are used to calculate the proposed project’s trip generation forecast. This publication provides a comprehensive evaluation of trip generation rates for a variety of land uses.

The project proposes to construct thirty-six (36) townhome dwelling units. The most appropriate trip rate for this land use is ITE Land Use 215: Single-Family Attached Housing. As described in the ITE Trip Generation Manual, Single-Family Attached Housing includes any single-family housing unit that shares a wall with an adjoining dwelling unit, whether the walls are for living space, a vehicle garage, or storage space. This land use includes duplexes (defined as a single structure with two distinct dwelling units, typically joined side-by-side and each with at least one outside entrance) and townhouses/rowhouses (defined as a single structure with three or more distinct dwelling units, joined side-by-side in a row and each with an outside entrance).

Table 1 shows the ITE trip generation rates utilized for the trip generation analysis of the proposed project land use and the proposed project trip generation forecasts based on those ITE trip generation rates.

Table 1 | Project Trip Generation Rates & Forecast1
Land Use (ITE Code) Quantity Units1
Weekday
AM Peak Hour PM Peak Hour Daily
In Out Total In Out Total
ITE Trip Generation Rate
Single-Family Attached
Housing (215) -- DU 25% 75% 0.48 59% 41% 0.57 7.20
Trip Generation Forecast
Single-Family Attached
Housing (215) 36 DU 4 13 17 12 9 21 259

1 Source: ITE Trip Generation Manual (11th Edition, 2021). 2 DU = Dwelling Unit
As shown in Table 1, based on the ITE trip generation rates, the proposed project is forecast to generate approximately 259 daily trips, which include approximately 17 AM peak hour trips and 21 PM peak hour trips.

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As specified in the Laguna Hills Traffic Study Guidelines, a traffic impact analysis, which includes LOS analysis for non-CEQA purposes, shall be required for a proposed project if a project adds 50 or more peak hour trips or 500 or more trip-ends per day. Based on the published rates from the latest ITE Manual, the proposed project is not expected to exceed 50 peak hour trips or 500 daily trips (i.e., 259 daily trips, 17 AM peak hour trips, and 21 PM peak hour trips). Therefore, the proposed project is not required to prepare a traffic impact analysis for non-CEQA purposes and is not expected to result in any significant adverse impacts on the operations of the roadway network and intersections.

VEHICLE MILES TRAVELED (VMT) SCREENING
The Laguna Hills Traffic Study Guidelines provides recommendations in the form of thresholds of significance and methodologies for identifying VMT related impacts. The first step in evaluating a land use project’s potential VMT impact is to perform an initial screening assessment utilizing the City of Laguna Hills VMT Screening Form for Land Use Projects (VMT Screening Form).

Projects that satisfy at least one of the screening requirements may be presumed to result in a less than significant impact to VMT. The following five (5) types of screening criteria are applicable:
• 100% Affordable Housing
• Located within ½ mile of Qualifying Transit
• Local Serving Land Use
• Low VMT Area
• Net daily Trips Less than 500 ADT
Appendix A located at the end of this letter report contains the completed City of Laguna Hills VMT Screening Form.

VMT Screening Type 1: 100% Affordable Housing – Not Satisfied Per the City of Laguna Hills VMT guidelines, if a project consists of 100% affordable housing, then the presumption can be made that it will have a less than significant impact on VMT. The project does not consist of 100% affordable housing and as a result, VMT Screening Criteria Type 1 is not met.

VMT Screening Type 2: Located within ½ mile of Qualifying Transit – Not Satisfied Per the City of Laguna Hills VMT guidelines, lead agencies generally should presume that certain projects (including residential, retail, and office projects, as well as projects that are a mix of these uses) proposed within one half (½) mile of an existing major transit stop or an existing stop along a high-quality transit corridor will have a less than significant impact on VMT.

Upon further review, the project is not located within one half mile of qualifying transit (e.g., major transit stop or high-quality transit corridor). As a result, VMT Screening Criteria Type 2 is not met.

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VMT Screening Type 3: Local Serving Land Use – Not Satisfied Per the City of Laguna Hills VMT guidelines, local serving land uses provide goods and services to the local community. Local serving land uses offer more opportunities for residents and employees to shop, dine and obtain services closer to home and work. Local serving uses can also include community resources that may otherwise be located outside of the local area. By improving destination proximity, local serving uses lead to shortened trip lengths and reduced VMT. Therefore, local serving uses may be presumed to have a less than significant impact on VMT.

Per Table 1: List of Local Serving Uses from the City of Laguna Hills VMT guidelines, the project is not considered a local serving land use. As a result, VMT Screening Criteria Type 3 is not met.

VMT Screening Type 4: Low VMT Area Screening - Satisfied Per the City of Laguna Hills VMT guidelines, projects located in areas with low VMT, and that incorporate similar features (i.e., density, mix of uses, transit accessibility), will tend to exhibit similarly low VMT. If a project is located in a Traffic Analysis Zone (TAZ) with VMT per capita or VMT per employee that is less than or equal to the citywide average, than the project is considered to be located in a low VMT area and can be presumed to have a less than significant impact on VMT. The project is consistent with the baseline land use assumptions for TAZ 1504. This includes a total of 982 households that exhibit similar travel demand characteristics as the proposed project. Therefore, it is reasonable to use the baseline statistics for estimating the project’s VMT.

As shown in OCTAM TAZ Map (Appendix A), the project is located within OCTAM TAZ 1504.

Table 2 summarizes the results of the low VMT area screening assessment.

Table 2 | VMT Screening Type 4: Low VMT Area Screening Assessment1,2 OCTAM TAZ VMT/Service Population
1504 12.9
City of Laguna Hills VMT Threshold of Significance 16.1 Potentially Significant Impact? (Yes/No) No
1 Source: Orange County Transportation Analysis Model (OCTAM) OCTAM is the preferred traffic model for screening and analyzing VMT in the City of Laguna Hills. The project is located within OCTAM TAZ 1504 which has a baseline VMT per Capita of 12.9. Because the project’s TAZ VMT does not exceed the citywide average VMT/capita of 16.1, the project is considered to be located in a low VMT area and can be presumed to have a less than significant impact on VMT.

As a result, VMT Screening Criteria Type 4 is met.

VMT Screening Type 5: Net Daily Trips Less Than 500 ADT - Satisfied Per the City of Laguna Hills VMT guidelines, projects that generate less than 500 net average daily trips (ADT) would not cause a substantial increase in the total citywide or regional VMT and are therefore presumed to have a less than significant impact on VMT.

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The City’s 500 ADT screening threshold is founded on substantial, locally tailored evidence as documented in Appendix C of the Laguna Hills VMT Guidelines. The VMT Guidelines show that projects below the 500 ADT screening threshold do not measurably increase citywide VMT or GHG emissions. Thus, the City’s screening threshold is consistent with CEQA Guidelines, which permit lead agencies to adopt thresholds of significance if those thresholds are supported by substantial evidence relevant to the agency's context.

Per Table 1 above, the project is forecast to generate approximately 259 daily trips. As a result, VMT Screening Criteria Type 5 is met.

Therefore, the proposed project is screened out based on VMT Screening Type 4: Low VMT Area Screening and VMT Screening Type 5: Net Daily Trips Less Than 500 ADT. As such, the proposed project may be presumed to have a less than significant VMT impact under CEQA. No further VMT analysis is required.

QUEUING ANALYSIS AT GATED DRIVEWAY
A queuing evaluation has been performed at the proposed gated access driveway. The purpose of this analysis is to determine whether adequate storage capacity is provided to allow vehicles to enter the project area without causing vehicles to spill back onto the public roadway (i.e., Mill Creek Drive).

To analyze potential vehicle queues, RK utilized the following studies:
• Entrance-Exit Design and Control for Major Parking Facilities, prepared by Robert W.

Crommelin, P.E., dated October 5, 1972.
• Residential Electronic Gate Service Study (REGSS), prepared by RK Engineering Group Inc., dated July 22, 2016.

Exhibit C illustrates the storage length provided at the project access. As shown in Exhibit C, the storage length measured from the gate to the curb face is approximately 91 feet and the callbox is located approximately 65 feet from the curb face.

As also shown in Exhibit C, the width of the project access driveway lanes is approximately 21.5 feet at the start of the median and expands to approximately 30 feet with an area for vehicles to bypass the visitor lane which is designed in accordance with Orange County Standard Plan 1107.

The gate queuing for residents was measured from the gate itself (i.e., 91 feet), whereas gate queuing for visitors would be measured from the callbox (i.e., 65 feet). Assuming an average car length of 19 feet (i.e., 22 feet of total spacing per vehicle), the project access driveway is expected to accommodate approximately 4 vehicles within the resident lane, and approximately 2 vehicles within the visitor lane without spilling onto Mill Creek Drive.

Arrival Rate
As shown previously in Table 1, the maximum inbound project peak hour traffic is forecast to be 14 vehicles during the PM peak hour. RK utilized the resident vs. visitor traffic splits as sourced in the

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Residential Electronic Gate Service Study (REGSS), dated July 22, 2016, prepared by RK Engineering Group Inc., to determine the arrival rate for both resident and visitor traffic. The REGSS is included in Appendix B.

Table 3 calculates the number of project trips entering the driveway by user type based on the project’s inbound trip generation and the resident vs. visitor traffic splits per the REGSS.

Table 3 | Crommelin Traffic Arrival Rate1
User Type
Maximum Peak Hour
Inbound Trip
Generation 2
Observed Average
Percent Split3,4
Crommelin Traffic
Arrival Rate (Number
of Vehicles per Hour)
Residents 12 79.52% 10
Visitors 20.48% 2

1 Source: Entrance-Exit Design and Control for Major Parking Facilities, prepared by Robert W. Crommelin, P.E., dated October 1972 2 Source: ITE Trip Generation Manual (11th Edition, 2021), referenced in Table 1. 3 Recommended gate service rate for combined user (Resident & Visitor) for a single-entry lane. 4 Source: Residential Electronic Gate Service Rate Study, dated July 22, 2016, prepared by RK Engineering Group Inc.

Per the REGSS, the observed entering PM peak hour traffic splits were 79.52% for residents and

20.48% for visitors. As shown in Table 3, based on the inbound trip generation and resident vs. visitor traffic splits per the REGSS, the arrival rates for residents and visitors are 10 vehicles per hour and 2 vehicles per hour, respectively.

Service Rate
Per the REGSS, the recommended service rates for two entry lanes utilized by residents and visitors are 220 vehicles per hour and 115 vehicles per hour, respectively.

Intensity Rate
The intensity rate is the ratio of the arrival rate to the service rate. Hence, the following intensity rates have been calculated per user type:
• Residents: [10 VPH / 220 VPH] = 0.05
• Visitors: [2 VPH / 115 VPH] = 0.02
Queue Findings
Exhibit D-1 and Exhibit D-2 show the results of the gate stacking analysis utilizing the Crommelin methodology for residents and visitors, respectively, by plotting the previously calculated intensity rate on the Crommelin nomograph and identifying the corresponding number of vehicles in the reservoir space behind the service position. The 95th percentile confidence interval is the typical engineering design standard.

Table 4 summarizes the results of the gate stacking analysis utilizing the Crommelin methodology.

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Table 4 | Gate Stacking Analysis Results
User Type
Crommelin Traffic
Arrival Rate
(Number of Vehicles per
Hour)1
Crommelin
Traffic
Service Rate
(Number of
Vehicles per
Hour)2
Crommelin
Traffic
Intensity Rate
Anticipated
Maximum
Queue
Behind Service
Position
(Vehicles)3
Anticipated
Maximum
Queue
Including
Service
Position
(Vehicles)4
Residents 10 220 0.05 1 2
Visitors 2 115 0.02 1 2

1 Crommelin traffic arrival rate based on the project's trip generation and residential inbound trip distribution at ultimate condition.
2 Recommended gate service rate for combined user (Resident & Visitor) for a single-entry lane.

Source: Residential Electronic Gate Service Rate Study, dated July 22, 2016, prepared by RK Engineering Group Inc. 3 Maximum Queue Behind Service Station Position estimated using the Crommelin graph (rounded up to the nearest vehicle). 4 An additional one vehicle is assumed to be in the service position.

As shown in Table 2, the 95th percentile vehicular queue for proposed driveway is forecast to be approximately two (2) vehicles during the peak hour for both the residential and visitor lane. As illustrated in Exhibit C, the proposed driveway provides a throat that can accommodate 4 vehicles in the resident lane and 2 vehicles in the visitor lane. As such, vehicles are not expected to spill back onto Mill Creek Drive.

VEHICLE TURNAROUND ASSESSMENT
Exhibit E-1 and Exhibit E-2 illustrates the turnaround movement of a standard passenger vehicle and a standard unit (SU) delivery truck, respectively, per the American Association of State Highway and Transportation Officials (AASHTO) standards at the project access driveway.

As shown in Exhibit E-1, a passenger vehicle would be required to drive over the designated parking spaces to be able to maneuver the turnaround area from the callbox in one turn. However, the project is proposing to exceed the number of parking spaces required. As such, these designated parking spaces would likely not be utilized often allowing visitors that need to turnaround the ability to complete the maneuver in one turn. Additionally, if those parking spaces are occupied a passenger vehicle would only need to complete a three-point turn to turnaround.

As shown in Exhibit E-2, a delivery truck would be required to make a multi-point turn to maneuver the turnaround area without driving over the center callbox median or into the parking spaces.

However, regardless of the parking spaces being occupied a delivery truck would be required to make a multi-point turn to maneuver a turnaround successfully. As such, even though the driveway is designed in accordance with Orange County Standard Plan 1107, a delivery truck would be obligated to make a multi-point turn due to the design of the drive-aisle.

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CONCLUSIONS
RK Engineering Group, Inc. has completed this Trip Generation and Vehicle Miles Traveled (VMT) Screening Assessment for the proposed Toll Brothers Laguna Hills Townhome Project.

As specified in the Laguna Hills Traffic Study Guidelines, a detailed traffic impact analysis will be required if a project adds 50 or more peak hour trips or 500 or more trip-ends per day. The project is forecast to generate approximately 259 daily trips which consists of 17 AM peak hour trips and 21 PM peak hour trips. As such, the proposed project is not required to prepare a traffic impact analysis and is not expected to result in any significant adverse impacts on the operations of the roadway network and intersections.

Furthermore, consistent with Laguna Hills Traffic Study Guidelines, the proposed project is screened out from a full VMT analysis based on the VMT Screening Type 4: Low VMT Area Screening and VMT Screening Type 5: Net Daily Trips Less Than 500 ADT. As such, the proposed project may be presumed to have a less than significant impact on VMT under CEQA. Therefore, no additional VMT analysis is required.

Additionally, a queuing evaluation has been performed at the proposed gated access driveway utilizing the Crommelin methodology. As a result, the 95th percentile vehicular queue for proposed driveway is forecast to be approximately two (2) vehicles during the peak hour for both a residential and visitor lane and are not expected to spill back onto Mill Creek Drive. Furthermore, a turnaround assessment was performed for a passenger vehicle and a SU delivery truck, per the AASHTO standards at the project access driveway and it was found that both vehicles would be required to make a multipoint turn to complete the maneuver without driving into the parking spaces.

RK Engineering Group, Inc. appreciates this opportunity to work on this project. If you have any questions regarding this review, or need further clarification, please contact us at (949) 474-0809.

Sincerely,
RK ENGINEERING GROUP, INC.

Justin Tucker, P.E., T.E. Sabrina Ayala
Principal Engineer I
Attachments

RK1234 // 1234-2024-01
Toll Brothers Laguna Hills
Townhome Project
Noise Impact Study
City of Laguna Hills, California
January 28, 2026

RK1234 // 1234-2024-01
Toll Brothers Laguna Hills Townhome Project
Noise Impact Study
City of Laguna Hills, California
Prepared for:

CITY OF LAGUNA HILLS, CA
24035 El Toro Road
Laguna Hills, CA 92653
Prepared by:

RK Engineering Group, Inc.
1401 Dove Street, Ste. 540
Newport Beach, CA 92660
Bryan Estrada, T.E.

Becca Morrison
Claire Stokes

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Table of Contents
Section Page

1.0 Introduction ................................................................................................................... 1-1

1.1 Purpose of Report & Study Objectives .............................................................................. 1-1

1.2 Site Location & Project Description ................................................................................... 1-1

1.3 Sensitive Receptors .............................................................................................................. 1-2

1.4 Summary of Analysis Results ............................................................................................... 1-2

2.0 Fundamentals of Noise .................................................................................................. 2-1

2.1 Sound, Noise, and Acoustics .............................................................................................. 2-1

2.2 Frequency and Hertz ............................................................................................................ 2-1

2.3 Sound Pressure Levels and Decibels ................................................................................. 2-1

2.4 Addition of Decibels ............................................................................................................ 2-1

2.5 Human Response to Changes in Noise Levels ................................................................. 2-1

2.6 Noise Descriptors ................................................................................................................. 2-2

2.7 Sound Propagation .............................................................................................................. 2-3

2.8 Vibration Descriptors ........................................................................................................... 2-5

2.9 Vibration Perception ............................................................................................................ 2-5

2.10 Vibration Propagation ......................................................................................................... 2-5

2.11 Construction-Related Vibration Level Prediction ............................................................. 2-6

3.0 Regulatory Setting ......................................................................................................... 3-1

3.1 State Regulations .................................................................................................................. 3-1

3.2 City of Laguna Hills Noise Regulations .............................................................................. 3-1

3.2.1 General Plan Noise Standards ............................................................................... 3-2

3.2.2 Municipal Code Noise Standards ......................................................................... 3-3

4.0 Study Method and Procedures ...................................................................................... 4-6

4.1 Noise Measurement Procedures and Criteria .................................................................. 4-6

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Table of Contents
Section Page

4.2 Stationary Noise Source Modeling .................................................................................... 4-7

4.3 Interior Noise Modeling ...................................................................................................... 4-7

4.4 Construction Noise Modeling ............................................................................................ 4-8

4.5 Construction Vibration Modeling ....................................................................................... 4-8

5.0 Existing Noise Environment ........................................................................................ 5-10

5.1 Noise Measurement Results ............................................................................................. 5-10

6.0 Operational Noise Impacts ............................................................................................ 6-1

6.1 Stationary Noise Source Impacts ........................................................................................ 6-1

6.1.1 HVAC Noise Impacts ............................................................................................... 6-1

6.1.2 Other Stationary Noise Source Impacts ............................................................... 6-3

6.1.3 Summary of Stationary Noise Source Impacts ..................................................... 6-3

6.2 Mobile Source Noise Impacts ............................................................................................. 6-4

6.2.1 Roadway Noise ........................................................................................................ 6-4

6.2.2 Airport Noise ............................................................................................................ 6-4

6.3 Noise/Land Use Compatibility ............................................................................................ 6-4

6.3.1 Exterior Noise/Land Use Compatibility ................................................................ 6-5

6.3.2 Interior Noise/Land Use Compatibility ................................................................. 6-6

7.0 Construction Noise and Vibration Impacts .................................................................... 7-1

7.1 Typical Construction Noise Levels ..................................................................................... 7-1

7.2 Construction Noise Impact Analysis .................................................................................. 7-3

7.3 Construction Vibration ......................................................................................................... 7-4

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List of Exhibits
Exhibit No.

Location Map ............................................................................................................................................................... A Site Plan ......................................................................................................................................................................... B Noise Monitoring Locations ....................................................................................................................................... C

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List of Tables
Table No. Page
Table 1-1 | CEQA Noise Impact Criteria ................................................................................................. 1-3 Table 2-1 | Construction Vibration Damage Criteria ............................................................................. 2-6 Table 2-2 | Suggested “n” Values Based on Soil Classes ..................................................................... 2-7 Table 3-1 | City of Laguna Hill Land Use Compatibility Guidelines1 ................................................... 3-2 Table 3-2 | City of Laguna Hills General Plan Noise Standards1 .......................................................... 3-3 Table 3-3 | City of Laguna Hills Municipal Code Noise Standards1 .................................................... 3-4 Table 4-1 | Referenced Stationary Noise Levels .................................................................................... 4-7 Table 5-1 | 24-Hour Noise Measurement Results – L-11 ...................................................................... 5-11 Table 5-2 | 24-Hour Noise Measurement Results – L-21 ...................................................................... 5-12 Table 6-1 | Stationary Noise Impacts at Residential Receptors ............................................................ 6-2 Table 6-2 | Stationary Noise Impacts at Commercial Receptors ......................................................... 6-3 Table 6-3 | Exterior Noise/Land Use Compatibility (dBA CNEL) ......................................................... 6-5 Table 6-4 | Future Interior Noise Levels (dBA CNEL) ............................................................................ 6-6 Table 7-1 | Typical Construction Noise Levels (dBA Leq)1 ................................................................... 7-2 Table 7-2 | Project Construction Noise Levels – Residential Receptors .............................................. 7-3 Table 7-3 | Project Construction Noise Levels – Commercial Receptors ............................................ 7-4 Table 7-4 | Typical Construction Vibration Levels1 ................................................................................ 7-5 Table 7-5 | Construction Vibration Impact Analysis – Residential Structures ..................................... 7-6 Table 7-6 | Construction Vibration Impact Analysis – Commercial Structures ................................... 7-7

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List of Appendices
Appendix ID
City of Laguna Hills General Plan Noise Element and Municipal Code Chapter 5-24 – Noise Control ..... A Field Data and Photos ................................................................................................................................................. B HVAC Manufacturer Specifications .......................................................................................................................... C Stationary Noise Calculation Worksheets ............................................................................................................... D Construction Noise and Vibration Calculation Worksheets ............................................................................... E

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1.0 Introduction

1.1 Purpose of Report & Study Objectives
The purpose of this report is to evaluate the potential noise impacts from the proposed Toll Brothers Laguna Hills Townhome Project (hereinafter referred to as “project”) and provide recommendations, if necessary, to minimize any project noise impacts.

The assessment was conducted pursuant to the California Environmental Quality Act (CEQA, California Public Resources Code Sections 21000, et seq.) and the standards and methodology follow the City of Laguna Hills Municipal Code and General Plan requirements.

The following is provided in this report:
• A description of the study area and the proposed project; • Information regarding the fundamentals of noise;
• Identification of the regulatory setting and applicable noise standards; • Establishment of the existing ambient noise environment at the project site; • Analysis of the project’s construction and operational noise impact to adjacent receptors; • Analysis of the project’s noise/land use compatibility and preliminary interior noise levels; and

1.2 Site Location & Project Description
The proposed project site will be constructed on the 2.43-acre parcel at 23161 Mill Creek Drive (APN 588-142-07) in the City of Laguna Hills, Orange County, California (Project Site). The project site is located on the west side of Mill Creek Drive, approximately 0.27 miles south of Lake Forest Drive, Mill Creek Drive, and Scientific Intersection. The project site is currently developed with a two-story office building, surface parking lot, and associated landscaping and pavement. Exhibit A shows the location map of the proposed project.

The proposed project consists of the demolition of the existing office building and associated surface parking lot and landscaping to construct 36 single-family-attached condominium residential units, parking, roadways, and associated infrastructure at a density of 14.8 dwelling units per acre (du/ac).

Two units will be deed-restricted for very low-income households, while the remaining 34 units are designated as above-moderate income.

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Construction activities are expected to consist of demolition, site preparation, grading, building construction, paving, and architectural coating. The project will require the import/export of up to approximately 35,000 cubic yards of earthwork material for grading purposes during construction.

Exhibit B shows the proposed site plan used for this analysis.

1.3 Sensitive Receptors
Sensitive receptors are considered land uses or other types of population groups that are more sensitive to noise exposure. There are several sensitive land uses adjacent to the project site as described below.

A project site location map, including sensitive receptor locations, is provided in Exhibit A.

Receptor-1 Existing residential land uses located to the west of the proposed project site. The nearest residential home located at Receptor-1 (marked as circle “1” on Exhibit A) is located approximately 80 feet west of the project site’s western boundary.

Receptor-2 Existing commercial land uses located to the north, east, and south of the proposed project site. the nearest commercial receptor located at Receptor-2 (marked as circle “2” on Exhibit A) is located directly adjacent to the project site’s southern boundary.

1.4 Summary of Analysis Results
Table 1-1 provides a summary of the noise analysis results, per the CEQA impact criteria checklist.

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Table 1-1 | CEQA Noise Impact Criteria
Noise Impact Criteria Potentially
Significant
Potentially
Significant
Unless
Mitigated
Less Than
Significant No Impact
Would the project result in:
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?
X
b) Generation of excessive groundborne vibration
or groundborne noise levels? X
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?
X

Legend Exhibit A Location Map 3075-2024-29 TOLL BROTHERS LAGUNA HILLS TOWNHOME PROJECT NOISE IMPACT STUDY // CITY OF LAGUNA HILLS, CA N 1 1 = Sensitive Receptor Location = Project Site Boundary ENGINEERING GROUP INC. 2

Exhibit B Site Plan 3075-2024-29 TOLL BROTHERS LAGUNA HILLS TOWNHOME PROJECT NOISE IMPACT STUDY // CITY OF LAGUNA HILLS, CA ENGINEERING GROUP INC. N

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2.0 Fundamentals of Noise
This section of the report provides basic information about noise and presents some of the terms used within the report.

2.1 Sound, Noise, and Acoustics
Sound is a disturbance created by a moving or vibrating source and is capable of being detected by the hearing organs. Sound may be thought of as mechanical energy of a moving object transmitted by pressure waves through a medium to a human ear. For traffic, or stationary noise, the medium of concern is air. Noise is defined as sound that is loud, unpleasant, unexpected, or unwanted.

2.2 Frequency and Hertz
A continuous sound is described by its frequency (pitch) and its amplitude (loudness). Frequency relates to the number of pressure oscillations per second. Low-frequency sounds are low in pitch (bass sounding) and high-frequency sounds are high in pitch (squeak). These oscillations per second (cycles) are commonly referred to as Hertz (Hz). The human ear can hear from the bass pitch starting out at 20 Hz all the way to the high pitch of 20,000 Hz.

2.3 Sound Pressure Levels and Decibels
The amplitude of a sound determines its loudness. The loudness of sound increases or decreases, as the amplitude increases or decreases. Sound pressure amplitude is measured in units of microNewton per square inch meter (N/m2), also called micro-Pascal (µPa). One µPa is approximately one hundred billionths (0.00000000001) of normal atmospheric pressure. Sound pressure level (SPL or Lp) is used to describe in logarithmic units the ratio of actual sound pressures to a reference pressure squared. These units are called decibels and abbreviated dB.

2.4 Addition of Decibels
Because decibels are on a logarithmic scale, sound pressure levels cannot be added or subtracted by simple plus or minus addition. When two (2) sounds of equal SPL are combined, they will produce an SPL 3 dB greater than the original single SPL. In other words, sound energy must be doubled to produce a 3 dB increase. If two (2) sounds differ by approximately 10 dB the higher sound level is the predominant sound.

2.5 Human Response to Changes in Noise Levels
In general, the healthy human ear is most sensitive to sounds between 1,000 Hz and 5,000 Hz, (Aweighted scale) and it perceives a sound within that range as being more intense than a sound with a higher or lower frequency with the same magnitude. For purposes of this report as well as with most environmental documents, the A-scale weighting is typically reported in terms of A-weighted decibel (dBA). Typically, the human ear can barely perceive the change in noise level of 3 dB. A change in 5

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dB is readily perceptible, and a change in 10 dB is perceived as being twice or half as loud. As previously discussed, a doubling of sound energy results in a 3 dB increase in sound, which means that a doubling of sound energy (e.g. doubling the volume of traffic on a highway), would result in a barely perceptible change in sound level.

2.6 Noise Descriptors
Noise in our daily environment fluctuates over time. Some noise levels occur in regular patterns, others are random. Some noise levels are constant, while others are sporadic. Noise descriptors were created to describe the different time-varying noise levels. The following are the most commonly used noise descriptors along with brief definitions.
• A-Weighted Sound Level. The sound pressure level in decibels as measured on a sound level meter using the A-weighted filter network. The A-weighting filter de-emphasizes the very low and very high frequency components of the sound in a manner similar to the response of the human ear. A numerical method of rating human judgment of loudness. • Ambient Noise Level. The composite of noise from all sources, near and far. In this context, the ambient noise level constitutes the normal or existing level of environmental noise at a given location.
• Community Noise Equivalent Level (CNEL). The average equivalent A-weighted sound level during a 24-hour day, obtained after addition of five (5) decibels to sound levels in the evening from 7:00 to 10:00 PM and after addition of ten (10) decibels to sound levels in the night before 7:00 AM and after 10:00 PM.
• Decibel (dB). A unit for measuring the amplitude of a sound, equal to 20 times the logarithm to the base 10 of the ratio of the pressure of the sound measured to the reference pressure, which is 20 micro-pascals.
• dBA. A-weighted sound level (see definition above).
• Equivalent Sound Level (Leq). The sound level corresponding to a steady noise level over a given sample period with the same amount of acoustic energy as the actual time varying noise level. The energy average noise level during the sample period. • Habitable Room. Any room meeting the requirements of the Uniform Building Code or other applicable regulations which is intended to be used for sleeping, living, cooking or dining purposes, excluding such enclosed spaces as closets, pantries, bath or toilet rooms, service rooms, connecting corridors, laundries, unfinished attics, foyers, storage spaces, cellars, utility rooms, and similar spaces.

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• L(n). The A-weighted sound level exceeded during a certain percentage of the sample time. For example, L10 is the sound level exceeded 10 percent of the sample time.

Similarly, L50, L90 and L99, etc.
• Noise. Any unwanted sound or sound which is undesirable because it interferes with speech and hearing, or is intense enough to damage hearing, or is otherwise annoying.

The State Noise Control Act defines noise as "...excessive undesirable sound...". • Outdoor Living Area. Outdoor spaces that are associated with residential land uses typically used for passive recreational activities or other noise-sensitive uses. Such spaces include patio areas, barbecue areas, jacuzzi areas, etc. associated with residential uses; outdoor patient recovery or resting areas associated with hospitals, convalescent hospitals, or rest homes; outdoor areas associated with places of worship which have a significant role in services or other noise-sensitive activities; and outdoor school facilities routinely used for educational purposes which may be adversely impacted by noise. Outdoor areas usually not included in this definition are: front yard areas, driveways, greenbelts, maintenance areas and storage areas associated with residential land uses; exterior areas at hospitals that are not used for patient activities; outdoor areas associated with places of worship and principally used for short-term social gatherings; and, outdoor areas associated with school facilities that are not typically associated with educational uses prone to adverse noise impacts (for example, school play yard areas). • Percent Noise Levels. See L(n).
• Sound Level (Noise Level). The weighted sound pressure level obtained by use of a sound level meter having a standard frequency-filter for attenuating part of the sound spectrum. • Sound Level Meter. An instrument, including a microphone, an amplifier, an output meter, and frequency weighting networks for the measurement and determination of noise and sound levels.
• Single Event Noise Exposure Level (SENEL). The dBA level which, if it lasted for one (1) second, would produce the same A-weighted sound energy as the actual event.

2.7 Sound Propagation
As sound propagates from a source it spreads geometrically. Sound from a small, localized source (i.e., a point source) radiates uniformly outward as it travels away from the source in a spherical pattern.

The sound level attenuates at a rate of 6 dB per doubling of distance. The movement of vehicles down a roadway makes the source of the sound appear to propagate from a line (i.e., line source) rather than a point source. This line source results in the noise propagating from a roadway in a cylindrical spreading versus a spherical spreading that results from a point source. The sound level attenuates for a line source at a rate of 3 dB per doubling of distance.

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As noise propagates from the source, it is affected by the ground and atmosphere. Noise models use hard site (reflective surfaces) and soft site (absorptive surfaces) to help calculate predicted noise levels.

Hard site conditions assume no excessive ground absorption between the noise source and the receiver. Soft site conditions such as grass, soft dirt or landscaping attenuate noise at an additional rate of 1.5 dB per doubling of distance. When added to the geometric spreading, the excess ground attenuation results in an overall noise attenuation of 3 dB per doubling of distance for a line source and 6.0 dB per doubling of distance for a point source.

Figure 1-1 | Typical Sound Levels from Indoor and Outdoor Noise Sources1 1 Source: AASHSTO. 1993. Guide on Evaluation and Abatement of Traffic Noise

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2.8 Vibration Descriptors
Ground-borne vibrations consist of rapidly fluctuating motions within the ground that have an average motion of zero. The effects of ground-borne vibrations typically only cause a nuisance to people, but at extreme vibration levels, damage to buildings may occur. Although ground-borne vibration can be felt outdoors, it is typically only an annoyance to people indoors where the associated effects of the shaking of a building can be notable. Ground-borne noise is an effect of ground-borne vibration that only exists indoors since it is produced from noise radiated from the motion of the walls and floors of a room and may also consist of the rattling of windows or dishes on shelves.

Several different methods are used to quantify vibration amplitude:
• PPV. Known as the peak particle velocity (PPV) which is the maximum instantaneous peak in vibration velocity, typically given in inches per second. • RMS. Known as the root mean squared (RMS) can be used to denote vibration amplitude. • VdB. A commonly used abbreviation to describe the vibration level (VdB) for a vibration source.

2.9 Vibration Perception
Typically, developed areas are continuously affected by vibration velocities of 50 VdB or lower. These continuous vibrations are not noticeable to humans whose threshold of perception is around 65 VdB.

Outdoor sources that may produce perceptible vibrations are usually caused by construction equipment, steel-wheeled trains, and traffic on rough roads, while smooth roads rarely produce perceptible ground-borne noise or vibration. The Federal Transit Administration (FTA) has published guidance relative to vibration impacts.

2.10 Vibration Propagation
There are three main types of vibration propagation: surface, compression, and shear waves. Surface waves, or Rayleigh waves, travel along the ground’s surface. These waves carry most of their energy along an expanding circular wavefront, similar to ripples produced by throwing a rock into a pool of water. P-waves, or compression waves, are body waves that carry their energy along an expanding spherical wavefront. The particle motion in these waves is longitudinal (i.e., in a “push-pull” fashion).

P-waves are analogous to airborne sound waves. S-waves, or shear waves, are also body waves that carry energy along an expanding spherical wavefront. However, unlike P-waves, the particle motion is transverse, or side-to-side and perpendicular to the direction of propagation.

As vibration waves propagate from a source, the vibration energy decreases in a logarithmic nature and the vibration levels typically decrease by 6 VdB per doubling of the distance from the vibration source. As stated above, this drop-off rate can vary greatly depending on the soil but has been shown

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to be effective enough for screening purposes in order to identify potential vibration impacts that may need to be studied through actual field tests.

2.11 Construction-Related Vibration Level Prediction2
Vibration activities are separated into two different categories. The vibration can be transient or continuous in nature. Each category can result in varying degrees of ground vibration, depending on the equipment used on the site. Operation of equipment causes ground vibrations that spread through the ground and diminish in strength with distance. Buildings in the vicinity of the project area respond to these vibrations with varying results ranging from no perceptible effects at the low levels to slight damage at the highest levels. The thresholds from the Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment Manual, September 2018, in the table below provide general guidelines as to the maximum vibration limits for when vibration becomes potentially damaging to structures.

The FTA Transit Noise and Vibration Impact Assessment Manual, September 2018, provides general thresholds and guidelines as to the vibration damage potential from vibratory impacts. Table 2-1 provides general vibration damage potential thresholds.

Table 2-1 | Construction Vibration Damage Criteria
Building/Structural Category PPV (in./sec.) Approximate LV 1 Reinforced-concrete, steel, or timber (no plaster) 0.50 102 Engineered concrete and masonry (no plaster) 0.30 98
Non-engineered timber and masonry buildings 0.20 94
Buildings extremely susceptible to vibration damage 0.12 90 1 RMD velocity in decibels, VdB re 1 micro-in/sec
Soil conditions have an impact on how vibration propagates through the ground. The Caltrans Transportation and Construction Vibration Guidance Manual, April 2020, provides suggested “n” values based on soil class. Table 2-2 outlines the manual’s suggested values and description. 2 Source: Caltrans Transportation and Construction Vibration Guidance Manual, April 2020.

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Table 2-2 | Suggested “n” Values Based on Soil Classes
Soil Class Description of Soil Material Suggested Value of “n”
I Weak or soft soils: loose soils, dry or partially saturated peat and muck, mud, loose beach sand, and dune sand. 1.4
II Most sands, sandy clays, silty clays, gravel, silts, and weathered rock. 1.3
III Hard soils: densely compacted sand, dry consolidated clay, consolidated glacial till, and some exposed rock. 1.1
IV Hard, component rock: bedrock, freshly exposed hard rock. 1.0

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3.0 Regulatory Setting
The proposed project is located in the City of Laguna Hills. The applicable noise regulations are described below.

3.1 State Regulations
The State of California has established noise insulation standards as outlined in Title 24 of the Building Standards Code which in some cases requires acoustical analyses to outline exterior noise levels and to ensure interior noise levels do not exceed the interior threshold.

Noise insulation design standards for residential dwellings are established in the 2022 California Building Code, Title 24, Part 2, Volume 1, Section 1206 Sound Transmission. The City is required by the State Housing Law to adopt these State codes as minimum performance standards. The City may enact stricter noise standards throughout the city or on a case-by-case basis if deemed necessary. In brief, the Title 24 noise standards require the following for allowable interior noise levels:

1. Interior noise levels due to exterior sources must not exceed a community noise equivalent level (CNEL) or a day-night level (LDN) of 45 dBA, in any habitable room.

2. Party wall and floor-ceiling assembly designs must provide a minimum STC of 50, based on lab tests. Field tested assemblies must provide a minimum noise isolation class (NIC) of

45. 3. Floor-ceiling assembly designs must provide for a minimum impact insulation class (IIC) of 50, based on lab tests. Field tested assemblies must provide a minimum FIIC of 45.

4. Penetrations or openings in sound rated assemblies must be treated to maintain required ratings.

3.2 City of Laguna Hills Noise Regulations
The proposed project is located in the City of Laguna Hills and is subject to the standards and regulations established by the City of Laguna Hills General Plan Noise Element and Municipal Code Chapter 5-24 – Noise Control, as discussed below.

A copy of the City of Laguna Hills General Plan and Municipal Code standards are provided in Appendix A.

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3.2.1 General Plan Noise Standards

3.2.1.1 Noise/Land Use Compatibility
The City of Laguna Hills General Plan establishes planning criteria for determining a development’s noise/land use compatibility based on the community noise equivalent level (CNEL). CNEL noise levels are typically used to evaluate mobile noise source impacts such as those from roadways.

Table 3-1 shows the City of Laguna Hills noise/land use compatibility standards for the land uses on and adjacent to the proposed project site, as prescribed in the General Plan.

Table 3-1 | City of Laguna Hill Land Use Compatibility Guidelines1 Land Use Category
Community Noise Exposure
(dBA CNEL)2
Normally
Acceptable
Conditionally
Acceptable
Normally
Unacceptable
Clearly
Unacceptable
Residential – Single family,
duplex, mobile home 60 and below 55 – 70 70 – 75 75 and above Residential – Multiple family 65 and below 60 – 70 70 – 75 75 and above Office Buildings, Business
Commercial, Professional 70 and below 67 – 77 75 and above -- 1 Source: City of Laguna Hills General Plan Noise Element, Figure N-1: Land Use Compatibility Guidelines. 2 Notes:

Normally Acceptable: Specified land use is satisfactory, based upon the assumption that any buildings involved are of normal conventional construction, without any special noise insulation requirements.

Conditionally Acceptable: New construction or development should be undertaken only after a detailed analysis of the noise reduction requirements is made and needed noise insulation features included in the design. Conventional construction, but with closed windows and fresh air supply systems or air conditioning will normally suffice.

Normally Unacceptable: New construction or development should generally be discouraged. If new construction or development does proceed, a detailed analysis of the noise reduction requirements must be made and needed noise insulation features included in the design.

Clearly Unacceptable: New construction or development clearly should not be undertaken.

3.2.1.2 Noise Standards
In addition to the above noise/land use compatibility guidelines, the General Plan has established the following noise standards which represent the maximum acceptable noise level as measured form any residential property in the City. Accordingly, it is unlawful to cause the noise level on any residential property to exceed the exterior noise standards listed in Table 3-2:

1. For a cumulative period of more than 30 minutes in any hour;

2. Plus 5 dBA for a cumulative period of more than 15 minutes in any hour;

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3. Plus 10 dBA for a cumulative period of more than 1 minute in any hour; or

4. Pus 20 dBA for any period of time.

In addition, it is unlawful to cause the noise level on any residential property to exceed the interior noise standards listed in Table 3-2:

1. For a cumulative period of more than 5 minutes in any hour;

2. Plus 5 dBA for a cumulative period of more than 1 minute in any hour; or

3. Plus 10 dBA for any period of time.

Table 3-2 | City of Laguna Hills General Plan Noise Standards1 Land Use Category
Allowable Noise Level
(dBA Leq)
Daytime
(7:00 a.m. to 10:00 p.m.)
Nighttime
(10:00 p.m. to 7:00 a.m.)
Residential - Exterior 55.0 50.0
Residential - Interior 55.0 45.0
Nonresidential 65.0 65.0
1 Source: City of Laguna hills General Plan Noise Element, Table N-2: Residential Noise Standards.

For the purposes of this analysis, the noise levels listed in Table 3-1 are used to evaluate the project’s noise/land use compatibility, and the noise levels listed in Table 3-2 are used to evaluate the project’s consistency with established plans, policies, and programs for noise control within the City.

3.2.2 Municipal Code Noise Standards

3.2.2.1 Noise Standards
Table 3-3 shows the exterior noise standards established in Chapter 5-24 of the City of Laguna Hills Municipal Code.

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Table 3-3 | City of Laguna Hills Municipal Code Noise Standards1 Land Use Category
Exterior Noise Level Thresholds
(dBA Leq)
Daytime
(7:00 a.m. – 10:00 p.m.)
Nighttime
(10:00 p.m. – 7:00 a.m.)
Residential - Exterior 55.0 50.0
Residential - Interior 55.0 45.0
Nonresidential 65.0 65.0
1 Source: City of Laguna Hills Municipal Code Chapter 5-24 – Noise Control.

Per the Municipal Code, it is unlawful for any person at any location within the City to operate, or cause to be operated, any source of sound at any location within the incorporated City or allow the creation of any noise on property owned, leased, occupied, or otherwise controlled by such person, which causes the noise level when measured on any other property, either incorporated or unincorporated, to exceed:

1. The noise standard for a cumulative period of more than thirty (30) minutes in any hour;

2. The noise standard plus five dBA for a cumulative period of more than fifteen (15) minutes in any hour;

3. The noise standard plus ten dBA for a cumulative period of more than five minutes in any hour;

4. The noise standard plus fifteen (15) dBA for a cumulative period of more than one minute in any hour; or

5. The noise standard plus twenty (20) dBA for any period of time.

In addition, it is unlawful to cause the noise level on any residential property to exceed the interior noise standards, as follows:

1. For a cumulative period of more than five (5) minutes in any hour;

2. Plus five (5) dBA for a cumulative period of more than one (1) minute in any hour; or

3. Plus ten (10) dBA for any period of time.

In the event the ambient noise level exceeds any of the first four noise limit categories above, the cumulative period applicable to said category is increased to reflect said ambient noise level. In the event the ambient noise level exceeds the fifth noise limit category, the maximum allowable noise level under said category is increased to reflect the maximum ambient noise level.

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3.2.2.2 Construction Noise Standards
Per the Municipal Code, noise sources associated with construction, repair, remodeling, or grading of any real property shall be exempted from the provisions of Chapter 5-24, provided said activities do not take place between the hours of eight p.m. and seven a.m. on weekdays, eight p.m. and eight a.m. on Saturday, or at any time on Sunday or a federal holiday.

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4.0 Study Method and Procedures
The following section describes the noise measurement procedures and locations, noise modeling procedures, and assumptions used in this analysis.

4.1 Noise Measurement Procedures and Criteria
Noise measurements are taken to determine the existing noise levels. A noise receiver or receptor is any location in the noise analysis in which noise might produce an impact. The following criteria are used to select measurement locations and receptors:
• Locations expected to receive the highest noise impacts, such as the nearest houses to the project site;
• Locations that are acoustically representative and equivalent to the area of concern; • Human land usage; and
• Sites clear of major obstructions and contamination.

RK conducted the sound level measurements in accordance with Caltrans technical noise specifications. All measurement equipment met American National Standards Institute (ANSI) specifications for sound level meters (ANSI S1.4: Specification for Sound Level Meter, 1983) Piccolo-II Type 2 integrating-averaging level meters were used to conduct noise measurements at the project site and property boundaries.

The Leq, Lmin, Lmax, L2, L8, L25, and L50 statistical data were recorded over the measurement time intervals and the information was utilized to define the noise characteristics for the project. The following gives a brief description of the procedures for sound level measurements:
• Microphones for sound level meters were placed five (5) feet above the ground; • Sound level meters were calibrated before each measurement; • Following the calibration of equipment, a windscreen was placed over the microphone; • Frequency weighting was set on “A” and slow response; and • Temperature and sky conditions were observed and documented.

Appendix B includes photos, field sheets, and measured noise data.

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4.2 Stationary Noise Source Modeling
Stationary noise generated by the project was modeled using a computer program that replicates the FHWA Noise Prediction Model (FHWA-RD-77-108). The FHWA model arrives at a predicted noise level through a series of adjustments to the reference energy noise level. For stationary sources, the following noise levels were applied to the model. The model outputs the projected noise level based on the following key parameters:
• Referenced noise level (i.e., how loud a source is at a specific distance); • Vertical and horizontal distances of sensitive receptor from the noise source; • Vertical and horizontal distances of noise barriers from the noise source and receptor; • Typical noise source spectra; and
• Topography.

The project proposes to install one (1) Carrier 37MUHAQ60AA3 outdoor heat pump for each dwelling unit. To model the noise generated by these units, manufacturer specifications were obtained and utilized. Table 4-1 indicates the referenced noise levels used in this analysis.

Table 4-1 | Referenced Stationary Noise Levels
Noise Source Distance from Source
(Feet)
Noise Levels
dBA Leq dBA Lmax
HVAC1 3.25 65 65
1 Noise level is representative of a single unit. Manufacturer specifications for the proposed HVAC units are provided in Appendix C.

4.3 Interior Noise Modeling
The interior noise level is the difference between the projected exterior noise level at the structure’s façade and the noise reduction provided by the structure itself. Typical building construction will provide a conservative 12 dBA noise level reduction with a “windows open” condition and a very conservative 20 dBA noise level reduction with “windows closed”. The interior noise level is estimated by subtracting the building shell design from the estimated exterior noise level.

The interior noise analysis is based on industry standards for building noise reduction established by the Federal Highway Administration (FHWA), the 2013 Caltrans Technical Noise Supplement to the Traffic Noise Analysis Protocol (TeNS), the California Office of Noise Control Catalog of Sound Transmission Class (STC) and Impact Insulation Class (IIC) Ratings for Wall and Floor/Ceiling Assemblies, and the California Building Standards Code, Title 24.

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The TeNS manual shows that the noise reduction due to building exteriors with ordinary sash windows (windows closed) is at least 20 decibels. By providing upgraded STC rated windows, the project design is considered adequate to meet interior noise standards. The building’s exterior walls will be constructed per the latest building code insulation requirements and provide occupants with the most protection from exterior noise. Insulated exterior walls, designed per the latest California Building Standards, would provide a minimum of STC 35-40. Windows, on the other hand, are one of the acoustically weakest parts of the structure. Therefore, for a conservative estimate of preliminary interior noise, the building’s noise reduction potential is limited to the STC of the windows.

4.4 Construction Noise Modeling
The construction noise vibration assessment is based on the General Assessment methodology set forth by the FTA’s Transit Noise and Vibration Impact Assessment Manual, Section 7 – Noise and Vibration during Construction. This analysis utilizes the Federal Highway Administration (FHWA) Roadway Construction Noise Model, together with several key construction parameters, to estimate future construction noise levels during each phase of construction. Consistent with the FTA General Assessment methodology, the following assumptions have been utilized in the construction noise model:
• Noise emission level (Lemission) – Determine the emission level at 50 feet according to noise from typical construction equipment.
• Usage factor (AdjUsage) – Assume a usage factor of one (1). This assumes a time period of one-hour with full power operation.
• Distance (D) – Assume that all equipment operates at the center of the project, or centerline for guideway or highway construction projects.
• Ground effect (G) – G equals zero (0) assuming free-field conditions and ignoring ground effects.
• The Leq.equip is determined only for the two noisiest pieces of equipment expected to be used in each phase of construction. The equipment noise levels are summed for each phase of construction using decibel addition.

Noise levels were projected from the center of the project site to the adjacent sensitive receptor property lines. Although some construction activity may occur closer to the adjacent receptors than the center of the project site, noise levels are based on an average distance from the center of the site per FTA General Assessment recommendations.

4.5 Construction Vibration Modeling
The construction vibration assessment is based on the methodology set forth within the Caltrans Transportation and Construction Induced Vibration Guidance Manual. The vibration impacts from

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bulldozers, heavy truck loading, vibratory rollers and compactors, and caisson drilling activity are analyzed. All vibratory activity is analyzed as a continuous and/or frequent event. This represents a conservative assessment, as construction equipment would in practice operate intermittently rather than continuously. It is expected that vibration levels will be highest during the paving phase. No impact pile driving is expected as part of this project.

Vibratory impacts were calculated from the nearest expected location of on-site construction to the nearest sensitive receptors and structures using the reference vibration levels, soil conditions, and the reference equation PPV= PPV ref (25/D)^n (in/sec) (from Caltrans Manual) where:
• PPV = reference measurement at 25 feet from the vibration source; • D = distance from equipment to property line; and
• n = vibration attenuation rate through ground (n = 1.1 was utilized for this study).

For the purposes of this analysis, hard soil conditions (i.e., densely compacted sand, dry consolidated clay, consolidated glacial till, and some exposed rock) were assumed.

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5.0 Existing Noise Environment
The existing noise environment for the project site and surrounding areas has been established based on noise measurement data collected by RK. The project setting is residential and commercial and the primary environmental noise impacting the project site is roadway noise from Mill Creek Drive.

5.1 Noise Measurement Results
To determine the existing noise level environment, RK conducted two (2) 24-hour noise measurements at the project site and receptors.

Noise levels were measured on May 21, 2024, using Piccolo-II Type 2 integrating-averaging sound level meters. The information was utilized to establish the noise characteristics of the existing ambient environment.

The noise monitoring locations were selected based on the proximity and location of adjacent sensitive receptors. Exhibit C graphically illustrates the location of the noise measurements. • Noise Monitoring Location 1 (L-1) was taken near the residential receptors to the west/southwest of the project site, approximately 35 feet northwest of the centerline of Mill Creek Drive.
• Noise Monitoring Location 2 (L-2) was taken near the commercial uses to the southeast of the project site, approximately 240 feet northeast of the centerline of Mill Creek Drive.

Noise measurements were conducted at the above-selected locations to determine the existing ambient noise environment at the project site and nearby sensitive receptors. The primary source of ambient noise during the measurement period was roadway noise along adjacent streets.

Results of the ambient noise measurements are shown in Tables 5-1 and 5-2. Appendix B includes photographs, field sheets, and measured noise data.

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Table 5-1 | 24-Hour Noise Measurement Results – L-11
Time dBA Leq Time dBA Leq
12:00 AM 53.0 12:00 PM 57.6
1:00 AM 43.9 1:00 PM 63.2
2:00 AM 43.3 2:00 PM 57.5
3:00 AM 41.6 3:00 PM 65.8
4:00 AM 46.3 4:00 PM 59.4
5:00 AM 58.0 5:00 PM 58.0
6:00 AM 68.3 6:00 PM 54.0
7:00 AM 67.8 7:00 PM 52.5
8:00 AM 60.9 8:00 PM 48.9
9:00 AM 62.8 9:00 PM 47.4
10:00 AM 64.0 10:00 PM 46.6
11:00 AM 57.6 11:00 PM 65.3
24-Hour CNEL 67.4
1 L-1 was measured on May 21, 2024.

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Table 5-2 | 24-Hour Noise Measurement Results – L-21
Time dBA Leq Time dBA Leq
12:00 AM 46.8 12:00 PM 56.3
1:00 AM 49.3 1:00 PM 53.9
2:00 AM 47.1 2:00 PM 53.8
3:00 AM 47.2 3:00 PM 53.7
4:00 AM 48.3 4:00 PM 57.3
5:00 AM 51.8 5:00 PM 55.0
6:00 AM 66.0 6:00 PM 56.2
7:00 AM 63.3 7:00 PM 53.7
8:00 AM 52.7 8:00 PM 56.3
9:00 AM 53.2 9:00 PM 50.0
10:00 AM 53.5 10:00 PM 48.6
11:00 AM 51.8 11:00 PM 49.0
24-Hour CNEL 63.5
1 L-2 was measured on May 21, 2024.

As shown in Table 5-1 and Table 5-2, the existing ambient noise levels at the proposed project site range from approximately 67.4 dBA CNEL to 63.5 dBA CNEL.

Legend Exhibit C Noise Monitoring Location 3075-2024-29 TOLL BROTHERS LAGUNA HILLS TOWNHOME PROJECT NOISE IMPACT STUDY // CITY OF LAGUNA HILLS, CA N 1 1 = Noise Monitoring Location = Project Site Boundary ENGINEERING GROUP INC. 2

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6.0 Operational Noise Impacts
The following noise impact analysis has been performed to determine whether the proposed project would result in a substantial increase in ambient noise levels in the vicinity of the site. Additionally, the noise analysis examines whether the project can meet the City of Laguna Hills and State of California requirements for residential exterior and interior noise exposure.

6.1 Stationary Noise Source Impacts
The proposed project consists of constructing and operating thirty-six (36) townhome dwelling units.

The main source of potential on-site noise would be HVAC equipment.

These types of on-site stationary noises would not typically be categorized as loud, unnecessary, or unusual noise that disturbs the peace or quiet of any neighborhood, or that causes discomfort or annoyance to any person of normal sensitiveness. In particular, social activities and vehicle-related noise are generally substantially less during the noise sensitive nighttime hours.

To help ensure on-site noise levels do not exceed the City of Laguna Hills General Plan and Municipal Code noise standards, the following stationary noise impact analysis has been prepared. The analysis considers all project noise sources operating continuously during daytime hours (7:00 a.m. to 10:00 p.m.) and nighttime hours (10:00 p.m. to 7:00 a.m.). The result is a worst-case assessment of impacts, as HVAC units would likely only operate intermittently throughout the day.

Stationary noise calculation worksheets are provided in Appendix D.

6.1.1 HVAC Noise Impacts
HVAC noise levels were modeled using manufacturer specifications for the proposed outdoor units, which are planned to be located at ground level and shielded behind noise barrier walls/enclosures.

To ensure a comprehensive assessment, the analysis assumes simultaneous operation of all units with direct line of sight to adjacent receptors. Noise from units blocked from line of sight is assumed to be adequately attenuated by intervening onsite structures.

To estimate noise level impacts at the adjacent residential receptors, the referenced noise level is input into the FHWA model and projected from the nearest proposed HVAC locations to the nearest residential habitable areas at a distance of approximately 100 feet. Per the City of Laguna Hills Municipal Code Section 5-24.100, “the location selected for measuring exterior noise levels shall be at any point on the affected property.” In this case, the property line adjacent to the project site consists of landscaped slope that does not contain and would not accommodate habitable structures.

Accordingly, receptors were placed at the nearest residential structures, which represent the actual locations of potential noise exposure. This approach is consistent with the intent of the Code requirement while providing a conservative and realistic assessment of potential impacts.

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To estimate noise level impacts at the adjacent commercial receptors, the referenced noise level is input into the FHWA model and projected from the nearest proposed HVAC locations to the nearest commercial property line, at a distance of approximately 10 feet.

The project site and surrounding area consist primarily of paved surfaces and vegetated areas.

Consistent with the inverse square law for stationary noise sources, stationary noise generated by the project was projected to the nearby receptors using a distance attenuation factor of 20, which results in a reduction of approximately 6 dBA per doubling of distance from the noise source.

Tables 6-1 and 6-2 show the projected operational noise levels at the nearest residential and commercial receptors, respectively. The noise modeling used in this analysis accounts for existing topographical changes in elevation in the vicinity of the project site and receptors, as well as attenuation provided by the proposed property line walls.

The project includes property line retaining walls along the western and southern project boundaries.

Along the western boundary, which separates the project site from adjacent residential receptors, the property line wall is anticipated to range in height from approximately 5 feet to approximately 15 feet.

To be conservative, potential noise impacts at residential receptors are modeled assuming a worstcase wall height of 5 feet. Along the southern boundary, which separates the project site from adjacent commercial receptors, the wall is anticipated to range in height from approximately 15 feet to approximately 19 feet. Accordingly, noise modeling for the southern boundary assumes a conservative wall height of 15 feet.

Stationary noise calculation worksheets are provided in Appendix D.

Table 6-1 | Stationary Noise Impacts at Residential Receptors Noise Source
Receptor Distance
from Noise Source
(feet)
Noise Level at Receptor
dBA Leq dBA Lmax
HVAC1 100 39.1 39.1
Noise Level Threshold (Day / Night) 55.0 / 50.0 75.0 / 70.0 Noise Level Exceeds Threshold? No / No No / No
1 Noise level is indicative of eight units and includes the attenuation effects of the proposed noise barriers/enclosures. For the purposes of this analysis, noise associated with the simultaneous operation of all units with direct line of sight to adjacent receptors is considered. Noise from units blocked from line of sight is assumed to be adequately attenuated by intervening onsite structures.

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Table 6-2 | Stationary Noise Impacts at Commercial Receptors Noise Source
Receptor Distance
from Noise Source
(feet)
Noise Level at Receptor
dBA Leq dBA Lmax
HVAC1 10 49.6 49.6
Noise Level Threshold (Day and Night) 65.0 65.0
Noise Level Exceeds Threshold? No No
1 Noise level is indicative of eight units and includes the attenuation effects of the proposed noise barriers/enclosures. For the purposes of this analysis, noise associated with the simultaneous operation of all units with direct line of sight to adjacent receptors is considered. Noise from units blocked from line of sight is assumed to be adequately attenuated by intervening onsite structures.

As shown in the tables above, noise levels generated by the project are not expected to exceed the City’s daytime or nighttime noise standards at any of the adjacent residential or commercial receptor locations.

6.1.2 Other Stationary Noise Source Impacts
In addition to onsite HVAC noise, the proposed project will generate noise associated with maintenance activities, including landscaping and trash removal. These types of on-site stationary noises would not typically be categorized as loud, unnecessary, or unusual noise that disturbs the peace or quiet of any neighborhood, or that causes discomfort or annoyance to any person of normal sensitiveness. Furthermore, these activities would typically occur during daytime hours only.

Per the City of Laguna Hills Municipal Code Section 5-24.070(I), property maintenance activities such as landscaping are exempt from noise standards when conducted between 7:00 a.m. and 8:00 p.m. on weekdays and Saturdays, or between 9:00 a.m. and 8:00 p.m. on Sundays and federal holidays. In compliance with the Municipal Code, no project-related maintenance activity, including landscaping, shall occur outside of the approved hours.

Furthermore, it should be noted that the project site is currently occupied by an existing commercial building, which includes trash removal and landscaping operations. As a result, these activities would not be new sources of noise generated by the project, and the project would not result in a substantial change in noise levels in the vicinity of the project site from these activities.

6.1.3 Summary of Stationary Noise Source Impacts
As discussed in Sections 6.1.1 and 6.1.2, the proposed project is not expected to generate stationary noise levels in excess of the noise standards established by the City, and the impact is considered less than significant.

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6.2 Mobile Source Noise Impacts

6.2.1 Roadway Noise
The main source of roadway noise in the vicinity of the project site is activity along Mill Creek Drive.

As described in the City’s General Plan Mobility Element, Mill Creek Drive is classified as a Collector (Commuter) Arterial, which can accommodate up to 10,000 vehicle trips per day.

Per California Department of Transportation (Caltrans) guidance, a doubling of traffic volume along a roadway would be required to increase ambient noise levels by 3 dBA or more3 . An increase in noise
levels by 3 dBA or more is an industry standard threshold of significance and is generally considered the point at which the human ear will perceive a change in noise level4 .

The project is expected to generate approximately 259 daily trips5 . Per Streetlight segment volume
data, the segment of Mill Creek Drive adjacent to the proposed project site has an average daily traffic (ADT) of approximately 1,877. As a result, the 259 daily trips generated by the proposed project will not double the amount of traffic along adjacent streets, and the potential increase in noise from project-related roadway activity would be less than 3 dBA. Therefore, the increase in roadway noise levels as a result of the project would be less than significant.

6.2.2 Airport Noise
The John Wayne Airport, located in Santa Ana, California, is the nearest airport to the proposed project site at a distance of approximately 8 miles. The project site is not located within the John Wayne Airport, or any other airport’s airport land use plan area.

Furthermore, as described above, the proposed project is not expected to expose people residing or working in the project area to excessive airplane noise levels. Therefore, the project would have no impact on exposing people residing or working in the area to excessive airplane noise.

6.3 Noise/Land Use Compatibility
The project proposes to site new townhome dwelling units along Mill Creek Drive. Traffic noise from Mill Creek Drive will be the primary source of noise impacting the project site and may expose future residents to noise levels above the City of Laguna Hills exterior noise thresholds for residential uses. 3 Source: Technical Noise Supplement to the Traffic Noise Analysis Protocol, California Department of Transportation (Caltrans), September 2013.
4 Source: Technical Noise Analysis Protocol for New Highway Construction, Reconstruction, and Retrofit Barrier Projects, California Department of Transportation (Caltrans), April 2020. 5 Source: Toll Brothers Townhome Project Trip Generation and Vehicle Miles Traveled (VMT) Screening Analysis and Gate Queueing Study, City of Laguna Hills (January 2025), prepared by RK.

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6.3.1 Exterior Noise/Land Use Compatibility
A noise/land use compatibility assessment has been prepared to help determine whether existing exterior noise levels affecting the project site exceed the City’s noise/land use compatibility threshold for residential land uses. This assessment is for informational and local planning purposes only and isn’t intended to serve as a CEQA impact determination, since it looks at existing noise conditions relative to future on-site sensitive receptors.

Exterior ambient noise levels are assessed at the first-row residential building façades of each dwelling unit facing Mill Creek Drive.

The first-row residential lots will be set back a minimum of approximately 55 feet from the centerline of Mill Creek Drive.

Future exterior noise levels are estimated based on the existing ambient noise level measurements collected by RK. To account for future increases in roadway volumes, a three-decibel increase has been applied to the measured noise levels. This is a conservative estimate, as a doubling of traffic volume along a roadway would by required to increase ambient noise levels by 3 dBA or more6 .

Table 6-3 shows the anticipated exterior noise levels at the first-row residential building façades.

Table 6-3 | Exterior Noise/Land Use Compatibility (dBA CNEL) Receptor Location Noise Monitoring Location Estimated Future Exterior Noise Levels
First-row building façades along
Mill Creek Drive L-1 70.4
As shown in Table 6-3, future exterior ambient noise levels are expected to be approximately 70.4 dBA CNEL and fall within the Normally Unacceptable noise/land use compatibility category.

Per the City of Laguna Hills General Plan, if new construction of Normally Unacceptable land uses proceeds, a detailed analysis of the noise reduction requirements must be made and the required noise insulation features must be included in the design.

In order to ensure that interior noise levels comply with County and State standards, the following preliminary interior noise analysis is provided.
6 Source: Technical Noise Supplement to the Traffic Noise Analysis Protocol, California Department of Transportation (Caltrans), September 2013.

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6.3.2 Interior Noise/Land Use Compatibility
The project must show that interior noise levels at the project site will not exceed the City of Laguna Hills and State of California noise/land use compatibility threshold for residential land uses. A preliminary interior noise analysis has been performed for the first row of habitable dwellings facing the adjacent roadways using a typical “windows open” and “windows closed” condition. A “windows open” condition assumes 12 dBA of noise attenuation from the exterior noise level. A “windows closed” condition” assumes 20 dBA of noise attenuation from the exterior noise level.

Table 6-4 indicates the future interior noise levels along the adjacent roadways.

Table 6-4 | Future Interior Noise Levels (dBA CNEL)
Exterior Façade
Study Location
Projected
Exterior
Noise
Level1
Interior
Noise
Standard
Required
Building Shell
Noise
Reduction
Interior Noise Level
with Standard Windows
(STC ~ 25) Required
STC Rating “Windows
Open”2
“Windows
Closed”3
First-row dwelling units
along Mill Creek Drive 70.4 45.0 25.4 58.4 50.4 28
1 Worst-case future exterior noise levels are based on existing ambient noise level measurements collected by RK. 2 A minimum of 12 dBA noise reduction is assumed with the “windows open” condition. 3 A minimum of 20 dBA noise reduction is assumed with the “windows closed" condition.

The project is expected to require a “windows closed” condition and upgraded STC-rated windows for all residential units facing Mill Creek Drive. To accommodate windows closed conditions, all residential units facing the adjacent roadways shall be equipped with adequate fresh air ventilation.

Exterior walls, designed per the latest California Building Standards are typically rated between STC 35-40. In order to ensure adequate noise attenuation is provided from the building shell, exterior walls should be designed to meet the required sound attenuation targets. Attic vents and other openings should be baffled and oriented away from facing the adjacent roadways.

Prior to issuance of building permits, the project proponent should demonstrate to the City Building Department that the proposed building shell and window assemblies will achieve exterior to interior noise reduction necessary to meet the State of California and City of Laguna Hills requirements.

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7.0 Construction Noise and Vibration Impacts
Temporary construction noise and vibration impacts have been assessed from the project site to the surrounding adjacent land uses. The degree of construction noise and vibration will vary depending on the type of construction activity taking place and the location of the activity relative to the surrounding properties.

During the construction period, the contractors will be required to comply with the City of Laguna Hills Municipal Code Chapter 5-24. Per the Municipal Code, noise sources associated with construction, repair, remodeling, or grading of any real property shall be exempted from the provisions of Chapter 5-24, provided said activities do not take place between the hours of eight p.m. and seven a.m. on weekdays, eight p.m. and eight a.m. on Saturday, or at any time on Sunday or a federal holiday. The Municipal Code does not include specific noise level limits for construction activities.

Because the City of Laguna Hills does not establish quantitative thresholds for construction-related noise, the proposed project’s potential construction noise impacts have been evaluated using the Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment (2006) criteria.

The FTA provides criteria for assessing construction noise impacts based on the potential for adverse community reaction. For residential and commercial uses, the General Assessment daytime noise thresholds are 90 dBA Leq and 100 dBA Leq, respectively, for a 1-hour period. However, for the purposes of a conservative analysis, the project’s construction-related noise impacts will be assessed utilizing the Detailed Analysis daytime noise thresholds of 80 dBA Leq and 85 dBA Leq, respectively, for residential and commercial land uses. It is assumed that no project-related construction would occur during the noise-sensitive nighttime hours.

Construction phasing and equipment usage assumptions are referenced from the Toll Brothers Laguna Hills Townhome Project Air Quality, Greenhouse Gas, And Energy Study, City of Laguna Hills, prepared by RK.

7.1 Typical Construction Noise Levels
Table 7-1 shows typical construction noise levels compiled by the Environmental Protection Agency (EPA) for common-type construction equipment. Typical construction noise levels are used to estimate potential project construction noise levels at the adjacent sensitive receptors.

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Table 7-1 | Typical Construction Noise Levels (dBA Leq)1 Equipment Type Noise Level at 50 Feet
Earth Moving
Compactors (Rollers) 73 - 76
Front Loaders 73 - 84
Backhoes 73 - 92
Tractors 75 - 95
Scrapers, Graders 78 - 92
Pavers 85 - 87
Trucks 81 - 94
Materials Handling
Concrete Mixers 72 - 87
Concrete Pumps 81 - 83
Cranes (Movable) 72 - 86
Cranes (Derrick) 85 - 87
Stationary
Pumps 68 - 71
Generators 71 - 83
Compressors 75 - 86
Impact Equipment
Pneumatic Wrenches 82 - 87
Jack Hammers, Rock Drills 80 - 99
Pile Drivers (Peak) 95-105
Other
Vibrators 68 - 82
Saws 71 - 82
1 Referenced noise levels from the Environmental Protection Agency (EPA).

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7.2 Construction Noise Impact Analysis
This assessment analyzes potential noise impacts of the two noisiest pieces of equipment during all expected phases of construction, including demolition, site preparation, grading, building construction, paving, and architectural coating. Noise levels are calculated based on an average distance of equipment over a 1-hour period to the nearest adjacent residential and commercial receptors. The project’s estimated construction noise levels have been calculated using the Federal Highway Administration Roadway Construction Noise Model Version 1.1.

Tables 7-2 and 7-3 show the noise level impacts from the center of the project site to the nearest residential and commercial property lines. Construction noise calculation worksheets are provided in Appendix E.

Table 7-2 | Project Construction Noise Levels – Residential Receptors Phase Equipment Quantity
Equipment
Noise Level at
215 ft.
(dBA Leq)
Combined
Noise Level
(dBA Leq)
Demolition
Concrete/Industrial Saws 1 76.9

78.0 Tractors/Loaders/Backhoes 1 71.3
Site Preparation
Graders 1 72.3

74.9 Tractors/Loaders/Backhoes 1 71.3
Grading
Graders 1 72.3

74.9 Tractors/Loaders/Backhoes 1 71.3
Building Construction
Cranes 1 67.9

73.0 Tractors/Loaders/Backhoes 1 71.3
Paving
Rollers 1 67.3

72.8 Tractors/Loaders/Backhoes 1 71.3
Architectural Coating Air Compressors 1 65.0 65.0
Worst-Case Construction Phase Noise Level (dBA Leq) 78.0 FTA Daytime Detailed Assessment Construction Noise Criteria (dBA Leq)1 80.0 Noise level exceeds criteria? No
1 Source: Federal Transit Administration (FTA). Transit Noise and Vibration Impact Assessment Manual, Section 7: Noise and Vibration During Construction.

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Table 7-3 | Project Construction Noise Levels – Commercial Receptors Phase Equipment Quantity
Equipment
Noise Level at
135 ft.
(dBA Leq)
Combined
Noise Level
(dBA Leq)
Demolition
Concrete/Industrial Saws 1 81.0

82.0 Tractors/Loaders/Backhoes 1 75.4
Site Preparation
Graders 1 76.4

78.9 Tractors/Loaders/Backhoes 1 75.4
Grading
Graders 1 76.4

78.9 Tractors/Loaders/Backhoes 1 75.4
Building Construction
Cranes 1 72.0

77.0 Tractors/Loaders/Backhoes 1 75.4
Paving
Rollers 1 71.4

76.8 Tractors/Loaders/Backhoes 1 75.4
Architectural Coating Air Compressors 1 69.1 69.1
Worst-Case Construction Phase Noise Level (dBA Leq) 82.0 FTA Daytime Detailed Assessment Construction Noise Criteria (dBA Leq)1 85.0 Noise level exceeds criteria? No
1 Source: Federal Transit Administration (FTA). Transit Noise and Vibration Impact Assessment Manual, Section 7: Noise and Vibration During Construction.

As shown in Tables 7-2 and 7-3, the project is not expected to generate noise levels which exceed the FTA Detailed Assessment construction noise thresholds for residential and commercial land uses.

As a result, the project impact would be less than significant.

7.3 Construction Vibration
To determine the vibratory impacts during construction, reference construction equipment vibration levels were utilized and then extrapolated to the façade of the nearest adjacent structures.

The nearest structures to the project site are the existing residential homes located to the west of the proposed project site and the existing commercial structure located to the south of the project site.

These structures are considered to be older residential homes and new commercial structures and are located approximately 100 feet and 10 feet, respectively, from the nearest expected areas of onsite construction activity.

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The construction of the proposed project is not expected to require the use of substantial vibrationinducing equipment or activities, such as pile drivers or blasting. The main source of vibration impacts during the construction of the project would be the operation of equipment such as bulldozer activity during site preparation, loading trucks during grading and excavation, and vibratory rollers during paving.

The construction vibration assessment utilizes the referenced vibration levels and methodology set forth within the Transit Noise and Vibration Impact Assessment Manual, Federal Transit Administration, September 2018. Table 7-4 shows the FTA-referenced vibration levels.

Table 7-4 | Typical Construction Vibration Levels1
Equipment
Peak Particle Velocity (PPV) at
25 Feet
(in./sec.)
Approximate Vibration Level
(LV) at 25 feet
Piledriver (impact)

1.518 (upper range) 112

0.644 (typical) 104
Piledriver (sonic)

0.734 upper range 105

0.170 typical 93
Clam shovel drop (slurry wall) 0.202 94
Hydromill 0.008 in soil 66
(slurry wall) 0.017 in rock 75
Vibratory Roller 0.210 94
Hoe Ram 0.089 87
Large bulldozer 0.089 87
Caisson drill 0.089 87
Loaded trucks 0.076 86
Jackhammer 0.035 79
Small bulldozer 0.003 58
1 Source: Federal Transit Administration (FTA). Transit Noise and Vibration Impact Assessment Manual, Section 7: Noise and Vibration During Construction.

Tables 7-5 and 7-6 show the project’s construction-related vibration analysis at the nearest residential and commercial structures to the project construction area. Construction vibration calculation worksheets are provided in Appendix E.

RK20568.2 // 3075-2024-29 7-6
The FTA provides criteria for potential damage resulting from construction vibration based on building type. The adjacent residential structures are estimated to be constructed in the 1970’s and are therefore considered to be older residential structures. Older residential buildings commonly include construction materials and interior finishes that may be more susceptible to cosmetic cracking from vibration when compared to newer construction, such as plaster or other brittle finishes.

Consistent with FTA criteria, these residential structures are conservatively evaluated using the vibration damage potential threshold of 0.20 inches per second PPV.

The nearest adjacent commercial building is assumed to be of modern, engineered construction with steel or reinforced concrete framing and interior finishes. Therefore, it is evaluated using the FTA category ‘reinforced concrete, steel, or timber (no plaster),’ with a vibration damage potential threshold of 0.50 inches per second PPV. This category is intended for engineered structures that are generally less susceptible to vibration-related cosmetic or structural damage than non-engineered buildings or unusually vibration-sensitive structures.

Table 7-5 | Construction Vibration Impact Analysis – Residential Structures Construction Activity
Distance to Nearest
Structure
(Feet)
Duration
Calculated Vibration
Level (PPV)
(in./sec.)
Large Bulldozer
100
Continuous/Frequent 0.019
Loaded Trucks Continuous/Frequent 0.017
Vibratory Rollers Continuous/Frequent 0.046
Worst-Case Construction Vibration Level 0.046
Vibration Damage Potential Threshold1 0.200
Vibration level exceeds threshold? No
1 Source: FTA Transit Noise and Vibration Impact Assessment Manual (September 2018) vibration damage potential threshold for “Non-engineered timber and masonry buildings”.

RK20568.2 // 3075-2024-29 7-7
Table 7-6 | Construction Vibration Impact Analysis – Commercial Structures Construction Activity
Distance to Nearest
Structure
(Feet)
Duration
Calculated Vibration
Level (PPV)
(in./sec.)
Large Bulldozer
15 Continuous/Frequent 0.156
Loaded Trucks Continuous/Frequent 0.133
Vibratory Rollers Continuous/Frequent 0.368
Worst-Case Construction Vibration Level 0.368
Vibration Damage Potential Threshold1 0.500
Vibration level exceeds threshold? No
1 Source: FTA Transit Noise and Vibration Impact Assessment Manual (September 2018) vibration damage potential threshold for “reinforced-concrete, steel, or timber (no plaster).” Based on the tables above, project-related construction activity is not expected to cause any potential damage to the nearest structures. Hence, the impact from construction-related vibration would be less than significant.

Appendices

Appendix A
City of Laguna Hills General Plan Noise Element and
Municipal Code Chapter 5-24 – Noise Control

Laguna Hills
GeneraL PLan
Noise Element
July 14, 2009

Noise
Consultants to the City
In Association with:

Austin Foust Associates
Stanley R. Hoffman Associates
Wilson Geosciences
Laguna Hills
General Plan
City Staff
Bruce Channing, City Manager
Donald White, Assistant City Manager
David Reynolds, Deputy City Manager/
Community Services Director
Vern Jones, Community Development Director
Julie Molloy, Project Manager
Peggy Johns, City Clerk
Ken Rosenfield, Public Services Director/
City Engineer
Steve Doan, Chief of Police Services
Greg Simonian, City Attorney
Jennifer Luna, Administrative Assistant
General Plan Advisory Committee
Larry Bertino Tom McCabe
Barbara Breazeale Carol Meyers
Bud Freedman John Oldroyd
Donald Froelich Melissa Palencia
Steve Geidt Charles Reames
Steve Kazarian Christina Salcido
Mary King Marty Samuel
Joe Martinez Don Sedgwick
Susan Masson Everett Stone
City Council
Mayor: Joel Lautenschleger
Mayor Pro Tem: Randal Bressette
Council Member: Melody Carruth
Council Member: R. Craig Scott
Council Member: L. Allan Songstad, Jr.

City of Laguna Hills General Plan Table of Contents
TOC-1
Table of Contents
noIse ........................................................................... n-1 Introduction .......................................................................N-1 Purpose and Scope of the Noise Element .............................N-1 Background ........................................................................N-1 Effects of Noise on People ..............................................N-2 Noise Plan ..........................................................................N-3 Noise Measurement .........................................................N-3 Noise and Land Use Planning ..........................................N-4 Noise Standards ...............................................................N-6 Transportation-Related Noise ...........................................N-9 Noise Control at Reception Sites ......................................N-9 Nontransportation-Related Noise ...................................N-10 Noise Ordinance ............................................................N-11 Goals and Policies .............................................................N-11 Noise and Land Use Planning ........................................N-12 Transportation-Related Noise .........................................N-12 Nontransportation-Related Noise ...................................N-13 Summary of Approach ......................................................N-13 Figures
N-1 Land Use Compatibility Guidelines ..............................N-5 N-2 Noise Contours 2008....................................................N-7 N-3 Noise Contours 2030....................................................N-8

City of Laguna Hills General Plan table of Contents
TOC-2
Tables
N-1 Common Noise Levels ....................................................... N-3 N-2 Residential Noise Standards ............................................... N-6 N-3 Description of Actions to Address Noise Issues ................. N-14

Introduction
Noise is unwanted sound that interferes with
living, working, and enjoying daily life. Exposure
to excessive noise can affect general well-being and
contributes to annoyance and undue stress. The
Noise Element is intended to reduce unwanted
sounds for the health, safety, and welfare of the
community. Removing or reducing significant
sources of noise where feasible will improve the
quality of life for Laguna Hills residents, workers,
and visitors.

Purpose and Scope
of the Noise Element
The purpose of the Noise Element is to identify and
assess existing noise sources in the community, and
to discuss the City’s role in ensuring comfortable
and safe noise levels in the future. As a part
of the General Plan process, citizens and City
officials identified goals for the future relating to
balancing land uses in the City, in part to minimize
incompatibilities and exposure to excessive noise
Noise
while providing the range of uses needed to maintain
a high quality of life. The goals, policies, and
programs will assist in achieving noise compatibility
between land uses.

The State of California recognizes the relationship
between noise and noise sensitive uses and has
adopted guidelines for noise elements that have been
followed in the preparation of this Element.

Background
Laguna Hill is located in an urbanized and developed
area and is subject to numerous noise sources,
primarily vehicular traffic on major roadways. The
City is also subject to typical urban noise sources
such as construction, police and fire department
sirens, landscaping equipment, barking dogs, and car
alarms.

Major noise sources in the City include traffic on
Interstate 5 (I‑5), State Route 73 (SR‑73), and
major arterials throughout the City. Truck traffic
is prevalent on these roadways and generates higher
noise levels relative to other vehicle types that travel

City of Laguna Hills General Plan Noise
N-2
on local roadways. Train traffic on the Atchison, Topeka, and Santa Fe Railway (AT&SF) rail line, which runs parallel to I-5, is another source of noise in the City. The AT&SF rail line traffic includes daily passenger (Amtrak), transit (Metrolink), and freight service. The nearest airport is John Wayne International Airport, approximately 10 miles northwest of Laguna Hills. The distance from the airport results in no noise impact from aircraft overflight.

The City has land uses that are sensitive to noise and may be significantly affected by interference from noise. Noise sensitive land uses include residences, schools, churches, hospitals, convalescent (nursing) homes, hotels, and certain parks. Excessive noise exposure to human receptors can cause adverse physical and psychological responses, in addition to interfering with speech and concentration, and diminishing the quality of life.

In addition to humans, protected animal species and their habitats may be considered sensitive receptors if located near construction and operational noise sources, especially during the species’ breeding seasons.

The City of Laguna Hills is located within a region where there is the potential habitat for noise sensitive bird species, such as the coastal California gnatcatcher and least Bell’s vireo, that nest or forage in upland scrub vegetation.

Effects of Noise on People
The effects of noise on people can include general annoyance, interference with speech communication, sleep disturbance, and in the extreme, hearing impairment or loss. While physical damage to the ear from an intense noise is rare, degradation of auditory acuity can occur within a community noise environment. Hearing loss occurs mainly due to chronic exposure to excessive noise, but it may be due to a single event such as an explosion. Table N-1 provides typical instantaneous noise levels of common activities.

Noise is generally defined as unwanted
sound. Its effects can range from
annoyance to health problems.

City of Laguna Hills General Plan Noise
N-3
Table N-1
Common Noise Levels
Noises Sound Level (dBA)
Threshold of Pain 140
Rock Band, Leaf Blower, Car Horn 110
Gas Lawn Mower, Train Approaching (Engines) 90
Diesel Truck, Food Blender 80
Gas Lawn Mower, Vacuum Cleaner 70
Normal Conversation, Heavy Traffic at 300 feet 60
Large Business Office, Dishwasher in Next Room 50
Quiet residential area 40
Library 30
Normal Breathing 10
Lowest Threshold of Human Hearing 0
These are typical noise levels. Distance from the source will reduce the noise level. A 10 dB increase doubles perceived loudness. Continued exposure to noise above 85 dB can cause hearing loss. A single exposure to 140 dB noise can cause some hearing loss.

Noise Plan
As Laguna Hills and surrounding communities continue to grow, noise levels associated with transportation‑ and nontransportation-related noise continue to increase. The City seeks ways to safeguard the community from excessive noise as the ambient noise level in the community rises.

The goals, policies, and the Plan in this section describe the means to reduce the negative effects of noise in the City. Programs addressing noise, contained in the Implementation Program section of the General Plan, are an extension of the Noise Plan and contain specific actions that the City uses to protect the community from excessive noise.

Noise Measurement
Evaluating noise is complex. Noise levels are measured as decibels (dB) on a logarithmic scale that quantifies sound intensity in a manner similar to the Richter scale used for earthquake magnitudes. Thus, doubling the energy of a noise source (e.g., traffic volume) would not double the noise level.

The human ear is not equally sensitive to all frequencies within the sound spectrum. The most common method to characterize sound is the “A‑weighted” sound level, or dB(A), which filters out noise frequencies not audible to the human ear, thereby weighting the audible frequencies.

Therefore, the dBA is used for noise measurements and standards involving the human perception of noise.

City of Laguna Hills General Plan Noise
N-4
In addition to instantaneous noise levels, noise levels measured over a period of time are used to assess noise limits and impacts. Noise levels measured over 1 hour are usually expressed as dBA Leq, the equivalent 1-hour noise level. Time of day is also an important factor for noise assessment; noise levels that may be acceptable during the day may interfere with the ability to sleep during evening or nighttime hours. Therefore, 24-hour noise levels are used. The community noise equivalent level (CNEL) is the cumulative noise exposure in a community during a 24‑hour period, which adds 5 dB(A) to evening sound levels (between 7:00 p.m. and 10:00 p.m.), and 10 dB(A) to the nighttime sound levels (between 10:00 p.m. and 7:00 a.m.). The day/ night average sound level (Ldn) is the same as the CNEL, except the 3-hour evening period is considered part of the daytime period.

In addition to noise measurement, traffic noise levels for freeways and arterials can be modeled using a traffic noise model with traffic volumes, mix, and speed characteristics.

Noise and Land Use Planning
Accumulation of noise from transportation and nontransportation sources determine the overall noise environment within a community.

Transportation noise refers to noise from automobile use, trucking, airport operations and rail operations. Nontransportation noise typically refers to noise from stationary sources such as commercial establishments, machinery, air conditioning systems, compressors, and landscape maintenance equipment.

Regardless of the type of noise, noise levels are highest near the source and substantially decrease with distance. Most noise impacts can be avoided when noise sources, sensitive land uses, and information about the future noise environment are considered in land use planning and development decisions. Land uses that generate significant noise should be separated from uses that are particularly sensitive to noise.

To establish the compatibility of various land uses with exterior noise levels, the City uses CNEL in its planning guidelines. CNEL takes into account heightened sensitivity of persons to noise during evening and nighttime periods.

Figure N-1 illustrates Laguna Hills’ land use compatibility guidelines.

Noise levels can be estimated and represented as noise contour lines, which indicate the area subject to a particular noise level. Figures N-2 and N-3 show the estimated existing and projected future noise contours in Laguna Hills, based on traffic volume counts and projected 2030 traffic volumes on the City’s arterials.

City of Laguna Hills General Plan Noise
N-5
Figure N-1
Land Use Compatibility
Guidelines

City of Laguna Hills General Plan Noise
N-6
The noise contours are used as a guide for land use and development decisions. Land uses within contours of 60 dB(A) or greater may be noise impacted depending on the use. When noise sensitive land uses are proposed within these contours, an acoustical analysis may be required. For a project to be approved in a noise impacted area, the analysis must demonstrate that the project is designed to attenuate noise to meet the City’s noise standards as defined in Table N-1. If the project is not designed to meet the noise standards, mitigation measures can be recommended in the analysis. If the analysis demonstrates that the noise standards can be met with implementation of the mitigation measures, the project can be approved with the mitigation measures required as conditions of project approval.

Noise Standards
Table N-2 summarizes the City of Laguna Hills exterior and interior noise standards. The standards represent the maximum acceptable noise levels as measured from any residential property in the City. Accordingly, it is unlawful to cause the noise level on any residential property to exceed the exterior noise standards:

1. for a cumulative period of more than 30 minutes in any hour;

2. plus 5 dB(A) for a cumulative period of more than 15 minutes in any hour;

3. plus 10 dB(A) for a cumulative period of more than 5 minutes in any hour;

4. plus 15 dB(A) for a cumulative period of more than 1 minute in any hour; or

5. plus 20 dB(A) for any period of time.

In addition, it is unlawful to cause the noise level on any residential property to exceed the interior noise standards (see Table N-2):

1. for a cumulative period of more than 5 minutes in any hour;

2. plus 5 dB(A) for a cumulative period of more than 1 minute in any hour; or

3. plus 10 dB(A) for any period of time.

Table N-2
Residential Noise Standards
Daytime Noise Standards
(7:00 am to 10:00 pm)
Nighttime Noise Standards
(10:00 pm to 7:00 am)
Exterior Noise Standards 55 dB(A) 50 dB(A)
Interior Noise Standards 55 dB(A) 45 dB(A)
Source: Laguna Hills Municipal Code Chapter 5-24.

Note: Standards are based on measurements taken from any residential property in the City.

City of Laguna Hills General Plan Noise City of Laguna Hills General Plan Noise N-7
Figure N-2 Existing Noise Contours
To be provided
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
Lake Forest Dr
Irvine Center Dr
Ridge Route Dr
El Toro Rd
El Toro Rd
Glenwood Dr
Alicia Pkwy
!"^$
!"^$
Greenfield Dr
Pa seo de Valencia
Laguna Hills D r
Oso Pkwy
La Paz Rd
Ridge Route Dr
Pkwy
A¥
Santa M aria Ave
Avenida de La Carlota
Crown Valley
Los Ali sos Blvd
Muirlands Blvd
Jeronimo Rd
Aliso Creek B lvd
2 1
3 4
7 9
6 5
8 10
11 LAGUNA NIGUEL

MISSION

VIEJO LAGUNA WOODS
IRVINE

LAKE FOREST
¹
0 0.25 0.5 1
Miles
Mo ulton
Pkwy
Noise Contours 2008
Figure N - 2
Noise Contours
Local Streets
City Boundary Major Streets
Freeway/ Toll Road
Source: Urban Crossroads, 2008.

CNEL 70
CNEL 65
CNEL 60
!! Measurement Locations
Note: Noise Contours are based
on flat terrain and hard surfaces.

City of Laguna Hills General Plan Noise
N-8
Figure N-3 Future Noise Contours
To be provided
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
!!
Lake Forest Dr
Irvine Center Dr
Ridge Route Dr
El Toro Rd
El Toro Rd
Glenwood Dr
Alicia Pkwy
!"^$
!"^$
Greenfield Dr
Pa seo de Valencia
Laguna Hills D r
Oso Pkwy
La Paz Rd
Ridge Route Dr
Pkwy
A¥
Santa M aria Ave
Avenida de La Carlota
Crown Valley
Los Alisos Blvd
Muirlands Blvd
Jeronimo Rd
Aliso Creek B lvd
2 1
3 4
7 9
6 5
10 11

LAGUNA NIGUEL

MISSION

LAGUNA WOODS VIEJO
IRVINE

LAKE FOREST
¹
0 0.25 0.5 1
Miles
Mo ulton
Pkwy
Noise Contours 2030
Figure N - 3
Noise Contours
Source: Urban Crossroads, 2008
Note: Noise Contours are based
on flat terrain and hard surfaces.

Local Streets
City Boundary Major Streets
Freeway/ Toll Road
CNEL 70
CNEL 65
CNEL 60
!! Measurement Locations

City of Laguna Hills General Plan Noise
N-9
The nonresidential exterior noise standard is always 65 dBA. Exempt from these standards are activities at any public or private educational facilities, or public park or playground; emergency equipment or work; construction activities during the day on Monday through Saturday; certain agricultural operations; and landscaping and maintenance.

Schools, hospitals, and churches are protected from noise sources that exceed the specified noise limits.

Transportation-Related Noise
Laguna Hills contains a number of transportation-related noise sources including freeways, major roadways, and railroad operations. I‑5, SR‑73, the railroad, and major roadways create high levels of noise that affect the overall quality of life in the community and are the major contributors of noise in the City. Some locations, such as areas adjacent to I-5 at Los Alisos, are regularly impacted by transportation noise. Reducing transportationrelated noise is necessary to improve the quality of life for noise sensitive land uses. Cost-effective strategies to reduce the influence of transportationrelated noise sources are an essential part of the Noise Element.

Noise Control at Reception Sites
The most efficient and effective means of controlling noise from transportation is to reduce noise at the source. However, the City has little direct control over noise produced by transportation sources because State noise regulations preempt location regulations. Because the City cannot control the noise at the source, City noise programs focus on reducing the impact of transportation noise reception sites.

The most effective way to mitigate transportation noise impacts on the City is by using the site development permit process and implementing CEQA. During the planning stages of the development process, potential impacts from transportation noise will be identified and mitigation measures will be required as needed to meet the City’s noise standards. Site planning, landscaping, natural topography and design, and construction noise barriers are the most common method of alleviating vehicular traffic and train noise impacts. Setbacks and buffer areas can also be used to achieve small noise reductions. The City can also use weight limitations on certain roadways and designate truck routes to reduce traffic noise in specific locations.

The City also encourages the construction and use of alternative modes of transportation such as alternative fuel vehicles, transit systems, and transit-oriented development (higher density, mixed use development near major rail and transit stops) to reduce transportation-related noise.

Alternative transportation modes can emit less noise per passenger than their automotive counterparts and can reduce traffic congestion.

City of Laguna Hills General Plan Noise
N-10
Noise Control at the Source
The California Vehicle Code contains noise regulations pertaining to the operation of all vehicles on public roads. These noise standards for cars, trucks, and motorcycles are enforced through coordination with the California Highway Patrol and the Orange County Sheriff’s Department.

The City also regulates traffic flow and coordinates with the California Highway Patrol and Orange County Sheriff’s Department to enforce speed limits to reduce traffic noise.

Nontransportation-Related Noise
The City contains a variety of land uses, many of which generate noise.

Noise from non-transportation-related sources includes industrial areas that involve heavy equipment and machinery, and commercial areas such as restaurants, bars, and entertainment establishments. Mechanical equipment such as heating, ventilating, and air conditioning units also generates noise throughout the City. Residential areas are also subject to noise from the use of pool equipment, landscape maintenance equipment, barking dogs, and other noise sources. Finally, construction activities throughout the City can temporarily elevate noise.

Application of the City’s noise regulations is the best means to control non-transportation-related noise. The Community Development Department and Orange County Sheriff’s Department cooperate to identify development or actives that violate noise regulations. The City’s municipal code gives the City the authority to enforce the noise standards through penalties and other abatement tactics.

Noise generated by new development is effectively controlled though the site development permit process, compliance with CEQA, and compliance with the City noise standards contained in this Noise Element and the City’s noise regulations. During preliminary stages in the development process, potential noise impacts will be identified and mitigation measures imposed.

When reviewing proposed mixed use and nonresidential projects, noise generation and potential impacts to surrounding development are considered. An acoustical analysis is required for projects that will generate noise potentially affecting sensitive receptors. Where significant impacts are identified, mitigation measures will be required.

Mitigation measures that could be applied when reviewing projects include acoustically treated and/or quiet designs for furnaces, fans, motors, compressors, pumps, and other mechanical equipment. The City may also require limited delivery hours and/or hours of operation to minimize impacts to adjacent residential or other noise sensitive uses.

In addition, all City departments must comply with State and federal

City of Laguna Hills General Plan Noise
N-11
Occupational Safety and Health Administration (OSHA) standards.

Any new equipment or vehicles purchased by the City will comply with local, State, and federal noise regulations, and the City will encourage landscaping contractors to utilize up to date noise-reducing equipment.

Noise Ordinance
The City Noise Ordinance is designed to protect people from nontransportation noise sources such as construction activity, commercial and industrial operations, machinery, and pumps and air conditioners.

Enforcing the ordinance includes requiring proposed development projects to show compliance with the ordinance, including operating in accordance with noise levels and hours of operation limits placed on the project site. The City also requires construction activity to comply with established work schedule limits. The ordinance is reviewed periodically for adequacy and amended as needed to address community needs and development patterns.

The City also has the opportunity to control noise and vibration transfers between adjacent land uses. Problems can arise when noise-producing uses are located immediately adjacent to sensitive uses, such as business park or light industrial uses near residences or schools. Additionally, increasing mixed use development throughout the City will place more sensitive residential uses alongside or above commercial uses, which could present challenges. The City’s Zoning Ordinance or any Specific Plan developed following adoption of the General Plan will include specific standards that address noise and vibration transfer in mixed use development.

Goals and Policies
The goals and policies section sets both broad and specific direction for the future of the City based on identified issues, as captured in the Guiding Themes and expressed by the community, City staff, and decision makers.

Three major issue areas are addressed in the goals and policies of the Noise Element. These major issues are:
• Using land use planning and development techniques to reduce noise and ensure compatibility between different land uses;
• Utilizing a variety of techniques and strategies to reduce transportation-related noise; and
• Requiring site design and other measures to reduce or maintain noise at acceptable levels for non-transportation-related noise.

City of Laguna Hills General Plan Noise
N-12
Noise and Land Use Planning
Land use directly affects noise compatibility because higher noise levels associated with certain land uses can encroach upon more sensitive land uses. Noise-producing and noise sensitive uses will be planned and/ or sufficiently buffered to ensure that sensitive uses are not exposed to unacceptable noise levels. Non-compatible land uses will incorporate noise attenuation and/or control measures in the development and design process to reduce noise.

Goal N-1: Reduce the effects of noise through proper land use planning and development techniques.

Policy N-1.1: Use the City’s noise/land use compatibility matrix (Figure N-1) as a guide for future planning and development decisions.

Policy N-1.2: Use transitional and buffer areas to separate excessive noise-generating uses from residential and other noise sensitive land uses.

Policy N-1.3: Limit future residential and other noise sensitive land uses in areas exposed to high levels of noise and/or utilize strategies to reduce noise experienced by sensitive uses at the point of reception.

Transportation-Related Noise
Transportation-related noise sources are the major contributors of noise in Laguna Hills and affect the overall quality of life. Reduction of transportation-related noise through a variety of measures is necessary to deal with the detrimental effects attributable to excessive noise.

Goal N-2: Reduce the impact of transportation-related noise on residential areas and other sensitive land uses.

Policy N-2.1: Reduce new transportation-related noise impacts to noise sensitive land uses through the use of noise control measures.

Policy N-2.2: Require noise-reducing construction techniques and site design measures for new development in areas impacted by transportation-related noise.

Policy N-2.3: Encourage new development to provide facilities that support the use of alternative transportation modes, such as walking, bicycling, carpooling and, where applicable, transit to reduce automobile traffic and its associated noise.

City of Laguna Hills General Plan Noise
N-13
Policy N-2.4: Consider using low-noise pavement surfaces on Mobility Element roadways that reduce motor vehicle traffic noise.

Policy N-2.5: Control truck traffic routing to reduce truck traffic impacts on noise sensitive land uses.

Policy N-2.6: Use traffic calming design and traffic control measures as needed to reduce vehicular speeds and associated noise levels in residential neighborhoods.

Nontransportation-Related Noise
Noise unrelated to vehicles, streets, and freeways also impacts the quality of life in Laguna Hills. Excessive noise from construction, business operations, and everyday activities negatively affects the community.

Site design, regulation, and enforcement measures will reduce nontransportation-related noise.

Goal N-3: Reduce the impact of non-transportation-related noise on residential areas and other sensitive land uses.

Policy N-3.1: Ensure noise sources from construction activities, entertainment venues, private development/residences, landscaping activities, and special events impacting noise sensitive lands use are maintained at acceptable levels.

Policy N-3.2: Require that commercial and mixed use structures be designed to prevent transfer of noise and vibration to residential and other noise sensitive land uses.

Policy N-3.3: Require commercial and mixed use developments to locate loading areas, parking lots, driveways, trash enclosures, mechanical equipment, and other noise sources away from residential development and, if necessary, to shield such noise sources with acoustic barriers.

Summary of Approach
The goals, policies, and programs in the Noise Element will help the City reduce noise from transportation and non-transportation-related sources.

The Noise Element encourages the use of land use compatibility measures and noise reduction techniques to ensure that redevelopment and new development are compatible with established uses. Table N-3 identifies the three major issue areas guiding the Noise Element. These major issues represent the direction the City will take in its noise goals, policies, and programs to implement the vision of Laguna Hills as captured in the Guiding Themes and expressed in the Noise Plan.

City of Laguna Hills General Plan Noise
N-14
Table N-3
Description of Actions to Address Noise Issues
Issues Element Section Policy Programs Figure Table
Noise and Land
Use Planning
Noise Noise and Land
Use Planning
N-1.1
through
N-1.3
N-1
through N-4
Figure N-1
(Land Use
Compatibility)
Figure N-3
(Future Noise
Contours)
Table N-2 (Noise
Standards)
Land Use
Respect
for Existing
Neighborhoods
LU-2.7 LU-6
TransportationRelated Noise Noise Transportationrelated Noise N-2.1
through
N-2.6
N-1, N-3,
N-5
NontransportationRelated Noise Noise Nontransportationrelated noise N-3.1
through
N-3.3
N-5

Appendix B
Field Data and Photos

Project: Engineer: B. Morrison Date: 5/20/2024
JN: 3075-2024-29
City: Laguna Hills, CA
Sound Level Meter: Calibration Record: Conditions:

Piccolo II Meter Input (dB) Time H: 68, L: 56
Serial #: P0222082204 1 94 2:26 p.m. 1
P0222082205 2 94 2:28 p.m. Northwest
3 -- -- Partly Cloudy
4 -- --
Calibrator:

BSWA
Serial #: 500732
Meter Settings:

A-Weighted Linear Slow 1/1 Octave _60_ Minute Intervals C-Weighted Impulse Fast 1/3 Octave L(n) Percentile Values Notes: Measurement Type:

Long-term (24-hour)
Short-term
= Noise Monitoring Location
Wind Direction:

Skies:

Noise measurements were taken at 1-hour intervals over a 24-hour period. Ambient noise sources during the measurement period consisted primarily of roadway activity along Mill Creek Drive.

Field Sheet
Toll Brothers Laguna Hills Townhome Project
Measurement Address: 23161 Mill Creek Drive
Temperature (°F):

Windspeed (m.p.h.):
1 2
1

Project: Engineer: B. Morrison Date: 5/20/2024
JN: 3075-2024-29
City: Laguna Hills, CA
Notes:

47.0 Field Photos - Noise Monitoring Location 1 (L-1)
Toll Brothers Laguna Hills Townhome Project
Measurement Address: 23161 Mill Creek Drive
Noise Monitoring Location 1 (L-1) was taken near the residential receptors to the west/southwest of the project site, approximately 35 feet northwest of the cetnerline of Mill Creek Drive.

Meter 1

Time Leq CNEL
12:00 AM 53.0 67.4
1:00 AM 43.9 67.42:00 AM 43.3 67.43:00 AM 41.6 67.44:00 AM 46.3 67.45:00 AM 58.0 67.46:00 AM 68.3 67.47:00 AM 67.8 67.48:00 AM 60.9 67.49:00 AM 62.8 67.4 10:00 AM 64.0 67.411:00 AM 57.6 67.4
12:00 PM 57.6 67.4
1:00 PM 63.2 67.42:00 PM 57.5 67.43:00 PM 65.8 67.44:00 PM 59.4 67.45:00 PM 58.0 67.46:00 PM 54.0 67.47:00 PM 52.5 67.48:00 PM 48.9 67.49:00 PM 47.4 67.4 10:00 PM 46.6 67.411:00 PM 65.3 67.4
Day Min: 47.4
Night Min 41.6
Noise Monitoring Location 1 Noise Monitoring Results (dBA Leq and CNEL)

0.0 10.020.030.040.050.060.070.080.090.0
100.0
12:00 AM
1:00 AM
2:00 AM
3:00 AM
4:00 AM
5:00 AM
6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 PM
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
6:00 PM
7:00 PM
8:00 PM
9:00 PM
10:00 PM
11:00 PM
Noise Level (dBA)
L-1 DBA LEQ AND CNEL
Leq CNEL

PROJECT: Toll Brothers Laguna Hills Townhome Project JOB #: 3075-2024-29 NOISE METER: Piccolo II SLM, 24-Hour Measurement DATE: 5/20/2024 LOCATION: 1 BY: B. Morrison
Time Leq Lmax Lmin L2 L8 L25 L50
12:00 AM 53.0 84.0 34.5 40.6 37.7 36.6 36.0
1:00 AM 43.9 68.1 34.5 49.8 40.2 37.3 36.42:00 AM 43.3 66.7 34.8 47.5 39.5 37.9 36.93:00 AM 41.6 67.8 36.5 43.2 40.8 39.7 39.04:00 AM 46.3 70.6 37.3 49.9 46.7 44.8 43.05:00 AM 58.0 75.0 42.9 68.3 63.9 50.7 47.76:00 AM 68.3 82.7 46.0 76.8 73.7 67.9 63.17:00 AM 67.8 95.4 45.3 71.7 65.8 57.2 52.58:00 AM 60.9 77.4 44.5 70.2 65.8 60.4 54.59:00 AM 62.8 81.5 45.9 72.0 67.8 62.4 52.4 10:00 AM 64.0 81.9 44.9 75.0 67.0 61.0 52.411:00 AM 57.6 74.7 44.9 67.6 62.4 53.8 48.4 12:00 PM 57.6 75.0 44.6 66.8 62.1 55.4 49.3
1:00 PM 63.2 79.8 44.9 72.4 67.7 62.0 54.12:00 PM 57.5 77.4 44.7 66.5 61.8 56.0 49.63:00 PM 65.8 84.2 45.4 75.0 70.4 65.4 53.44:00 PM 59.4 80.0 44.3 68.5 63.1 55.8 48.85:00 PM 58.0 77.1 44.7 67.6 62.4 55.2 48.76:00 PM 54.0 73.2 42.4 63.7 58.6 49.8 45.77:00 PM 52.5 72.9 39.7 61.8 55.4 46.5 43.58:00 PM 48.9 74.5 38.6 57.9 48.8 42.4 40.99:00 PM 47.4 71.2 38.8 55.4 46.5 44.1 42.4 10:00 PM 46.6 66.5 37.1 51.5 47.2 45.5 44.311:00 PM 65.3 92.0 36.3 69.2 49.4 40.6 39.0 Daytime 61.3 95.4 37.1 69.8 64.5 58.6 50.5
Nighttime 61.4 92.0 34.5 69.0 65.1 59.0 54.3
Noise Monitoring Location 1 Noise Monitoring Results (dBA Leq and Ln)

0.0 10.020.030.040.050.060.070.080.090.0
100.0
12:00 AM
1:00 AM
2:00 AM
3:00 AM
4:00 AM
5:00 AM
6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 PM
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
6:00 PM
7:00 PM
8:00 PM
9:00 PM
10:00 PM
11:00 PM
Decibel (dB)
Time
L-1 DBA LEQ AND LN
Leq Lmax Lmin L2 L8 L25 L50

Project: Engineer: B. Morrison Date: 5/20/2024
JN: 3075-2024-29
City: Laguna Hills, CA
Notes:

47.0 Field Photos - Noise Monitoring Location 2 (L-2)
Toll Brothers Laguna Hills Townhome Project
Measurement Address: 23161 Mill Creek Drive
Noise Monitoring Location 2 (L-2) was taken near the commercial uses to the east of the project site, approximatley 240 feet northeast of the centerline of Mill Creek Drive.

Meter 2

Time Leq CNEL
12:00 AM 46.8 63.5
1:00 AM 49.3 63.52:00 AM 47.1 63.53:00 AM 47.2 63.54:00 AM 48.3 63.55:00 AM 51.8 63.56:00 AM 66.0 63.57:00 AM 63.3 63.58:00 AM 52.7 63.59:00 AM 53.2 63.5 10:00 AM 53.5 63.511:00 AM 51.8 63.5
12:00 PM 56.3 63.5
1:00 PM 53.9 63.52:00 PM 53.8 63.53:00 PM 53.7 63.54:00 PM 57.3 63.55:00 PM 55.0 63.56:00 PM 56.2 63.57:00 PM 53.7 63.58:00 PM 56.3 63.59:00 PM 50.0 63.5 10:00 PM 48.6 63.511:00 PM 49.0 63.5
Day Min: 50.0
Night Min 46.8
Noise Monitoring Location 2 Noise Monitoring Results (dBA Leq and CNEL)

0.0 10.020.030.040.050.060.070.080.090.0
100.0
12:00 AM
1:00 AM
2:00 AM
3:00 AM
4:00 AM
5:00 AM
6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 PM
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
6:00 PM
7:00 PM
8:00 PM
9:00 PM
10:00 PM
11:00 PM
Noise Level (dBA)
L-2 DBA LEQ AND CNEL
Leq CNEL

PROJECT: Toll Brothers Laguna Hills Townhome Project JOB #: 3075-2024-29 NOISE METER: Piccolo II SLM, 24-Hour Measurement DATE: 5/20/2024 LOCATION: 2 BY: B. Morrison
Time Leq Lmax Lmin L2 L8 L25 L50
12:00 AM 46.8 61.0 45.4 48.1 47.5 47.0 46.4
1:00 AM 49.3 70.3 45.7 52.0 47.9 47.4 46.72:00 AM 47.1 52.2 45.9 48.3 47.9 47.5 46.83:00 AM 47.2 51.2 46.1 48.1 47.9 47.6 46.94:00 AM 48.3 53.2 46.2 50.3 49.7 48.9 48.25:00 AM 51.8 64.3 47.8 60.4 53.8 50.4 49.46:00 AM 66.0 82.0 49.7 73.7 71.0 67.0 61.87:00 AM 63.3 87.2 48.2 72.0 66.0 57.5 53.88:00 AM 52.7 65.6 47.6 60.1 54.9 52.4 51.29:00 AM 53.2 76.2 46.9 56.9 53.0 51.0 50.0 10:00 AM 53.5 74.9 47.4 58.4 56.7 54.0 51.911:00 AM 51.8 69.4 48.2 56.3 53.6 51.6 50.5 12:00 PM 56.3 81.9 48.3 64.6 58.4 53.8 51.5
1:00 PM 53.9 73.6 48.2 61.6 56.9 52.8 50.82:00 PM 53.8 69.7 48.2 61.5 56.7 53.0 51.73:00 PM 53.7 71.4 48.4 62.9 54.8 51.7 50.54:00 PM 57.3 85.9 47.9 62.6 56.4 53.0 51.75:00 PM 55.0 73.0 49.9 60.7 57.3 54.1 52.66:00 PM 56.2 76.8 47.7 65.5 58.0 52.2 50.47:00 PM 53.7 73.6 47.4 57.6 56.7 53.8 50.48:00 PM 56.3 65.4 48.1 59.0 58.3 58.0 57.89:00 PM 50.0 59.0 48.2 51.2 50.7 50.3 49.9 10:00 PM 48.6 65.6 45.5 50.8 50.3 49.3 48.211:00 PM 49.0 65.0 45.0 55.3 51.6 48.6 47.4 Daytime 55.9 87.2 45.5 63.3 58.0 53.7 52.1
Nighttime 57.5 82.0 45.0 65.0 62.2 58.4 53.8
Noise Monitoring Location 2 Noise Monitoring Results (dBA Leq and Ln)

0.0 10.020.030.040.050.060.070.080.090.0
100.0
12:00 AM
1:00 AM
2:00 AM
3:00 AM
4:00 AM
5:00 AM
6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 PM
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
6:00 PM
7:00 PM
8:00 PM
9:00 PM
10:00 PM
11:00 PM
Decibel (dB)
Time
L-2 DBA LEQ AND LN
Leq Lmax Lmin L2 L8 L25 L50

Appendix C
Stationary Noise Calculation Worksheets

Project: Date: 1/21/2026
JN: 3075-2024-29
Noise Source: HVAC - Single Unit Engineer: B. Morrison
Location: Nearest adjacent residential receptor
OBS DIST= 100.0
DT WALL= 7.0
DT W/OB= 93.0
HTH WALL= 5.0 ********
BARRIER = 0.0 (0=WALL,1=BERM)
OBS HTH= 12.0
NOISE HTH= 4.0 BARRIER+
OBS EL = 0.0 TOPO SHIELDING = -5.09
NOISE EL = 0.0 NOISE HTH EL= 4.0
DROP-OFF= 20.0 (20 = 6 dBA PER DOUBLING OF DISTANCE)
Distance (ft.) Leq Lmax L2 L8 L25 L50
REF LEVEL 3.25 65.0 65.0 65.0 65.0 65.0 65.0
PROJ LEVEL 100 35.2 35.2 35.2 35.2 35.2 35.2
SHIELDING 100 -5.1 -5.1 -5.1 -5.1 -5.1 -5.1
ADJ LEVEL 100 30.1 30.1 30.1 30.1 30.1 30.1
NOISE LEVEL REDUCTION DUE TO DISTANCE = -29.76233278
Stationary Noise Calculations - Based on FHWA-RD-77-108 Toll Brothers Laguna Hills Townhome Project Noise Impact Study Noise Input Data
Noise Output Data (dBA)

Project: Date: 1/21/2026
JN: 3075-2024-29
Noise Source: Combined HVAC Units Engineer: B. Morrison Location: Nearest adjacent residential receptor
Noise Source Leq Lmax L2 L8 L25 L50
HVAC - 1 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 2 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 3 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 4 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 5 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 6 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 7 30.1 30.1 30.1 30.1 30.1 30.1
HVAC - 8 30.1 30.1 30.1 30.1 30.1 30.1
Total 39.1 39.1 39.1 39.1 39.1 39.1
dB Adder
Noise Levels (dBA)
Toll Brothers Laguna Hills Townhome Project Noise Impact Study

Project: Date: 1/21/2026
JN: 3075-2024-29
Noise Source: HVAC - Single Unit Engineer: B. Morrison
Location: Nearest adjacent commercial receptor
OBS DIST= 10.0
DT WALL= 7.0
DT W/OB= 3.0
HTH WALL= 15.0 ********
BARRIER = 0.0 (0=WALL,1=BERM)
OBS HTH= 12.0
NOISE HTH= 4.0 BARRIER+
OBS EL = 0.0 TOPO SHIELDING = -14.60
NOISE EL = 0.0 NOISE HTH EL= 4.0
DROP-OFF= 20.0 (20 = 6 dBA PER DOUBLING OF DISTANCE)
Distance (ft.) Leq Lmax L2 L8 L25 L50
REF LEVEL 3.25 65.0 65.0 65.0 65.0 65.0 65.0
PROJ LEVEL 10 55.2 55.2 55.2 55.2 55.2 55.2
SHIELDING 10 -14.6 -14.6 -14.6 -14.6 -14.6 -14.6
ADJ LEVEL 10 40.6 40.6 40.6 40.6 40.6 40.6
NOISE LEVEL REDUCTION DUE TO DISTANCE = -9.76233278
Stationary Noise Calculations - Based on FHWA-RD-77-108 Toll Brothers Laguna Hills Townhome Project Noise Impact Study Noise Input Data
Noise Output Data (dBA)

Project: Date: 1/21/2026
JN: 3075-2024-29
Noise Source: Combined HVAC Units Engineer: B. Morrison Location: Nearest adjacent commercial receptor
Noise Source Leq Lmax L2 L8 L25 L50
HVAC - 1 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 2 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 3 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 4 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 5 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 6 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 7 40.6 40.6 40.6 40.6 40.6 40.6
HVAC - 8 40.6 40.6 40.6 40.6 40.6 40.6
Total 49.6 49.6 49.6 49.6 49.6 49.6
dB Adder
Toll Brothers Laguna Hills Townhome Project Noise Impact Study
Noise Levels (dBA)

Appendix D
Construction Noise and Vibration Calculation Worksheets

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Demolition Residential 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Concrete Saw No 100 89.6 215 0
Tractor No 100 84 215 0
Equipment *Lmax Leq
Concrete Saw 76.9 76.9
Tractor 71.3 71.3
Total 76.9 78
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Site Preparation Residential 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Grader No 100 85 215 0
Tractor No 100 84 215 0
Equipment *Lmax Leq
Grader 72.3 72.3
Tractor 71.3 71.3
Total 72.3 74.9
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Grading Residential 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Grader No 100 85 215 0
Tractor No 100 84 215 0
Equipment *Lmax Leq
Grader 72.3 72.3
Tractor 71.3 71.3
Total 72.3 74.9
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Building Construction Residential 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Crane No 100 80.6 215 0
Tractor No 100 84 215 0
Equipment *Lmax Leq
Crane 67.9 67.9
Tractor 71.3 71.3
Total 71.3 73
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Paving Residential 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Roller No 100 80 215 0
Tractor No 100 84 215 0
Equipment *Lmax Leq
Roller 67.3 67.3
Tractor 71.3 71.3
Total 71.3 72.8
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Architectural Coating Residential 47.4 47.7 47.4
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Compressor (air) No 100 77.7 215
Equipment *Lmax Leq
Compressor (air) 65 65
Total 65 65
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Demolition Commercial 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Concrete Saw No 100 89.6 135 0
Tractor No 100 84 135 0
Equipment *Lmax Leq
Concrete Saw 81 81
Tractor 75.4 75.4
Total 81 82
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Site Preparation Commercial 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Grader No 100 85 135 0
Tractor No 100 84 135 0
Equipment *Lmax Leq
Grader 76.4 76.4
Tractor 75.4 75.4
Total 76.4 78.9
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Grading Commercial 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Grader No 100 85 135 0
Tractor No 100 84 135 0
Equipment *Lmax Leq
Grader 76.4 76.4
Tractor 75.4 75.4
Total 76.4 78.9
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Building Construction Commercial 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Crane No 100 80.6 135 0
Tractor No 100 84 135 0
Equipment *Lmax Leq
Crane 72 72
Tractor 75.4 75.4
Total 75.4 77
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Paving Commercial 47.4 47.7 47.4
Spec Actual Receptor Estimated
Impact Lmax Lmax Distance Shielding
Description Device Usage(%) (dBA) (dBA) (feet) (dBA)
Roller No 100 80 135 0
Tractor No 100 84 135 0
Equipment *Lmax Leq
Roller 71.4 71.4
Tractor 75.4 75.4
Total 75.4 76.8
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
Baselines (dBA)
---- Receptor #1 ----
Roadway Construction Noise Model (RCNM),Version 1.1

Report date: 2/25/2025
Case Description: Toll Brothers Laguna Hills Townhome Project Description Land Use Daytime Evening Night
Architectural Coating Commercial 47.4 47.7 47.4
Spec Actual Receptor
Impact Lmax Lmax Distance
Description Device Usage(%) (dBA) (dBA) (feet)
Compressor (air) No 100 77.7 135
Equipment *Lmax Leq
Compressor (air) 69.1 69.1
Total 69.1 69.1
*Calculated Lmax is the Loudest value.

Results
Calculated (dBA)
Equipment
---- Receptor #1 ----
Baselines (dBA)
Roadway Construction Noise Model (RCNM),Version 1.1

Project: Toll Brothers Laguna Hills Townhomes Project Date: 2/25/2025 Activity: Construction Vibration JN: 3075-2024-29
Location: Nearest Residential Structures Engineer: B. Morrison PPV = 0.019 in/sec
Equipment Type = 2 Large Bulldozer
PPVref
= 0.089 Reference PPV at 25 ft.

D = 100.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Vibratory Roller 0.210
Large Bulldozer 0.089
Small Bulldozer 0.003
Crack and Seat 2.400
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref
(25/D)n (in/sec)
Equipment PPV Reference Levels
Caisson Drilling 0.089
Loaded Trucks 0.076
Jackhammer 0.035
Equipment Reference PPV

Project: Toll Brothers Laguna Hills Townhomes Project Date: 2/25/2025 Activity: Construction Vibration JN: 3075-2024-29
Location: Nearest Residential Structures Engineer: B. Morrison PPV = 0.017 in/sec
Equipment Type = 4 Loaded Trucks
PPVref
= 0.076 Reference PPV at 25 ft.

D = 100.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Crack and Seat 2.400
Loaded Trucks 0.076
Jackhammer 0.035
Small Bulldozer 0.003
Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson Drilling 0.089
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref
(25/D)n (in/sec)
Equipment PPV Reference Levels
Equipment Reference PPV

Project: Toll Brothers Laguna Hills Townhomes Project Date: 2/25/2025 Activity: Construction Vibration JN: 3075-2024-29
Location: Nearest Residential Structures Engineer: B. Morrison PPV = 0.046 in/sec
Equipment Type = 1 Vibratory Roller
PPVref
= 0.210 Reference PPV at 25 ft.

D = 100.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Crack and Seat 2.400
Loaded Trucks 0.076
Jackhammer 0.035
Small Bulldozer 0.003
Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson Drilling 0.089
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref
(25/D)n (in/sec)
Equipment PPV Reference Levels
Equipment Reference PPV

Project: Toll Brothers Laguna Hills Townhomes Project Date: 2/25/2025 Activity: Construction Vibration JN: 3075-2024-29
Location: Nearest Commercial Structures Engineer: B. Morrison PPV = 0.156 in/sec
Equipment Type = 2 Large Bulldozer
PPVref
= 0.089 Reference PPV at 25 ft.

D = 15.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Crack and Seat 2.400
Loaded Trucks 0.076
Jackhammer 0.035
Small Bulldozer 0.003
Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson Drilling 0.089
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref
(25/D)n (in/sec)
Equipment PPV Reference Levels
Equipment Reference PPV

Project: Toll Brothers Laguna Hills Townhomes Project Date: 2/25/2025 Activity: Construction Vibration JN: 3075-2024-29
Location: Nearest Commercial Structures Engineer: B. Morrison PPV = 0.133 in/sec
Equipment Type = 4 Loaded Trucks
PPVref
= 0.076 Reference PPV at 25 ft.

D = 15.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Crack and Seat 2.400
Loaded Trucks 0.076
Jackhammer 0.035
Small Bulldozer 0.003
Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson Drilling 0.089
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref
(25/D)n (in/sec)
Equipment PPV Reference Levels
Equipment Reference PPV

Project: Toll Brothers Laguna Hills Townhomes Project Date: 2/25/2025 Activity: Construction Vibration JN: 3075-2024-29
Location: Nearest Commercial Structures Engineer: B. Morrison PPV = 0.368 in/sec
Equipment Type = 1 Vibratory Roller
PPVref
= 0.210 Reference PPV at 25 ft.

D = 15.00 Distance from Equipment to receiver in ft.
n = 1.10 Vibration attenuation rate through the ground
Type
1 2
3 4
5 6
7 Crack and Seat 2.400
Loaded Trucks 0.076
Jackhammer 0.035
Small Bulldozer 0.003
Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson Drilling 0.089
Vibration Impact Analysis
Vibration Input/Output Data
PPV = PPVref
(25/D)n (in/sec)
Equipment PPV Reference Levels
Equipment Reference PPV

RK1234 // 1234-2024-01
Toll Brothers Laguna Hills Townhome Project
Air Quality, Greenhouse Gas, and Energy
Impact Study
City of Laguna Hills, California
January 28, 2026

RK1234 // 1234-2024-01
Toll Brothers Laguna Hills Townhome Project
Air Quality, Greenhouse Gas, and Energy
Impact Study
City of Laguna Hills, California
Prepared for:

CITY OF LAGUNA HILLS, CA
24035 El Toro Road
Laguna Hills, CA 92653
Prepared by:

RK Engineering Group, Inc.
1401 Dove Street, Ste. 540
Newport Beach, CA 92660
Bryan Estrada, T.E.

Becca Morrison
Claire Stokes

RK20569.2 // 3075-2024-30
Table of Contents
Section Page

1.0 Introduction ................................................................................................................... 1-1

1.1 Purpose of Report & Study Objectives .............................................................................. 1-1

1.2 Site Location & Project Description ................................................................................... 1-1

1.3 Sensitive Receptors .............................................................................................................. 1-2

1.4 Summary of Analysis Results ............................................................................................... 1-2

2.0 Air Quality Setting ......................................................................................................... 2-1

2.1 Description of Air Pollutants ............................................................................................... 2-1

2.2 Federal and State Ambient Air Quality Standards ........................................................... 2-4

2.3 Attainment Status ................................................................................................................. 2-6

2.4 South Coast Air Quality Management District (SCAQMD) ............................................. 2-7

2.4.1 SCAQMD Rules and Regulations .......................................................................... 2-8

2.5 Local Climate and Meteorology ....................................................................................... 2-10

2.6 Local Air Quality ................................................................................................................. 2-11

3.0 Global Climate Change Setting ..................................................................................... 3-1

3.1 Greenhouse Gases (GHGs) ................................................................................................. 3-1

3.2 GHG Regulatory Setting – State of California ................................................................... 3-3

3.3 GHG Emissions Inventory .................................................................................................... 3-3

4.0 Modeling Parameters and Assumptions ........................................................................ 4-1

4.1 Construction Assumptions .................................................................................................. 4-1

4.2 Localized Construction Analysis Modeling Parameters .................................................. 4-2

4.3 Operational Assumptions ................................................................................................... 4-3

4.3.1 Mobile Source Emissions ....................................................................................... 4-3

4.3.2 Energy Source Emissions ....................................................................................... 4-5

4.3.3 Area Source Emissions ........................................................................................... 4-6

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Table of Contents
Section Page

4.3.4 Other Sources of Operational Emissions ............................................................. 4-6

5.0 Significance Thresholds ................................................................................................. 5-1

5.1 Air Quality Regional Significance Thresholds .................................................................. 5-1

5.2 Air Quality Localized Significance Thresholds ................................................................. 5-1

5.3 GHG Significance Thresholds ............................................................................................. 5-2

5.3.1 SCAQMD GHG Interim Significance Thresholds ................................................ 5-2

6.0 Air Quality Impact Analysis ............................................................................................ 6-1

6.1 Short-Term Air Quality Impacts – Construction ................................................................ 6-1

6.1.1 Regional Emissions – Construction ....................................................................... 6-1

6.1.2 Localized Emissions – Construction ...................................................................... 6-2

6.1.3 Fugitive Dust – Construction .................................................................................. 6-2

6.1.4 Odors – Construction .............................................................................................. 6-2

6.1.5 Asbestos – Construction ......................................................................................... 6-3

6.1.6 Diesel Particulate Matter – Construction .............................................................. 6-3

6.2 Long-Term Air Quality Impacts – Operation ..................................................................... 6-4

6.2.1 Regional Emissions – Operation ............................................................................ 6-4

6.2.2 Localized Emissions – Operations ......................................................................... 6-5

6.2.3 Odors – Operation ................................................................................................... 6-5

6.2.4 Toxic Air Contaminants – Operations ................................................................... 6-5

7.0 Greenhouse Gas Impact Analysis................................................................................... 7-1

7.1 Greenhouse Gas Emissions – Construction ...................................................................... 7-1

7.2 Greenhouse Gas Emissions – Operations ......................................................................... 7-1

8.0 Energy Impact Analysis .................................................................................................. 8-1

8.1 Study Objectives................................................................................................................... 8-1

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Table of Contents
Section Page

8.2 Utility Providers ..................................................................................................................... 8-1

8.3 Project Energy Consumption .............................................................................................. 8-1

8.3.1 Electricity Consumption ......................................................................................... 8-1

8.3.2 Natural Gas Consumption ...................................................................................... 8-2

8.3.3 Petroleum Consumption ........................................................................................ 8-2

8.4 Summary of Project Energy Consumption ........................................................................ 8-7

8.5 Energy Impacts ..................................................................................................................... 8-7

8.5.1 Energy Impact – A .................................................................................................... 8-7

8.5.2 Energy Impact – B .................................................................................................... 8-8

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List of Exhibits
Exhibit No.

Location Map ............................................................................................................................................................... A Site Plan ......................................................................................................................................................................... B

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List of Tables
Table No. Page
Table 1-1 | Project Land Use Summary ................................................................................................... 1-2 Table 1-2 | CEQA Air Quality Impact Criteria ......................................................................................... 1-3 Table 1-3 | CEQA GHG Impact Criteria ................................................................................................... 1-3 Table 1-4 | CEQA Energy Impact Criteria ............................................................................................... 1-4 Table 2-1 | Federal and State Ambient Air Quality Standards (AAQS)1 ............................................. 2-5 Table 2-2 | South Coast Air Basin Attainment Status1 ........................................................................... 2-7 Table 2-3 | Meteorological Summary1 .................................................................................................... 2-10 Table 2-4 | Local Air Quality1 .................................................................................................................. 2-12 Table 3-1 | Global Warming Potential of Greenhouse Gases1, 2 .......................................................... 3-2 Table 3-2 | GHG Emissions Inventory 1 .................................................................................................... 3-3 Table 4-1 | Construction Equipment Assumptions 1 .............................................................................. 4-2 Table 4-2 | Operational Vehicle Miles Traveled 1 ................................................................................... 4-4 Table 4-3 | Operational Vehicle Mix 1 ...................................................................................................... 4-5 Table 4-4 | Operational Water Usage and Waste Generation 1 ........................................................... 4-7 Table 5-1 | SCAQMD Regional Significance Thresholds1 ..................................................................... 5-1 Table 5-2 | SCAQMD Localized Significance Thresholds (LSTs)1 ........................................................ 5-2 Table 6-1 | Regional Construction Emissions ......................................................................................... 6-1 Table 6-2 | Localized Construction Emissions ........................................................................................ 6-2 Table 6-3 | Regional Operational Emissions .......................................................................................... 6-4 Table 6-4 | Localized Operational Emissions ......................................................................................... 6-5 Table 7-1 | Construction Greenhouse Gas Emissions ........................................................................... 7-1 Table 7-2 | Operational Greenhouse Gas Emissions ............................................................................ 7-2 Table 8-1 | Utility Providers ....................................................................................................................... 8-1 Table 8-2 | Project Electricity Consumption1 .......................................................................................... 8-2 Table 8-3 | Construction Off-Road Equipment Energy Consumption ................................................ 8-3 Table 8-4 | Construction On-Road Equipment Energy Consumption ................................................. 8-4 Table 8-5 | Operational Trips Energy Consumption - Annual ............................................................. 8-6 Table 8-6 | Total Annual Energy Consumption ...................................................................................... 8-7

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List of Appendices
Appendix ID
CalEEMod Emissions Outputs .................................................................................................................................. A EMFAC2021 Vehicle Fuel Consumption Data ....................................................................................................... B

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1.0 Introduction

1.1 Purpose of Report & Study Objectives
The purpose of this air quality, greenhouse gas, (GHG) and energy impact study is to determine whether the construction and operation of the Toll Brothers Laguna Hills Townhome Project (hereinafter referred to as “project”) would cause significant air quality, GHG, or energy impacts.

This assessment was conducted within the context of the California Environmental Quality Act (CEQA, California Public Resources Code Sections 21000, et seq.). The methodology follows the California Air Resources Board (CARB), the SCAQMD, and City of Laguna Hills recommendations for quantification of emissions and evaluation of potential impacts.

This study also evaluates the project’s potential impact on energy conservation pursuant to CEQA Guidelines, Appendix F, Energy Conservation Analysis, and the use of renewable energy sources.

1.2 Site Location & Project Description
The proposed project site will be constructed on the 2.43-acre parcel at 23161 Mill Creek Drive (APN 588-142-07) in the City of Laguna Hills, Orange County, California (Project Site). The project site is located on the west side of Mill Creek Drive, approximately 0.27 miles south of Lake Forest Drive, Mill Creek Drive, and Scientific Intersection. The project site is currently developed with a two-story office building, surface parking lot, and associated landscaping and pavement. Exhibit A shows the location map of the proposed project.

The proposed project consists of the demolition of the existing office building and associated surface parking lot and landscaping to construct 36 single-family-attached condominium residential units, parking, roadways, and associated infrastructure at a density of 14.8 dwelling units per acre (du/ac).

Two units will be deed-restricted for very low-income households, while the remaining 34 units are designated as above-moderate income.

Construction activities are expected to consist of demolition, site preparation, grading, building construction, paving, and architectural coating. During construction, the project would demolish approximately 34,200 square feet of building area, 29,461 square feet of asphalt, and 5,000 square feet of hardscape. The project would require the import/export of up to approximately 35,000 cubic yards of earthwork material for grading purposes. All mobile off-road diesel construction equipment including generators will be equipped with Tier 4 low emission “clean diesel” engines.

Exhibit B shows the proposed site plan used for this analysis. Table 1-1 summarizes the land use assumptions used for this analysis.

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Table 1-1 | Project Land Use Summary
Project Land Use CalEEMod Land Use Category Quantity Metric1 Townhomes Condo/Townhouse 36 DU
Onsite Paved Surfaces Parking Lot 0.92 AC
1 DU = Dwelling unit.

AC = Acres.

1.3 Sensitive Receptors
Sensitive receptors are considered land uses or other types of population groups that are more sensitive to air pollution exposure. Sensitive population groups include children, the elderly, the acutely and chronically ill, and those with cardio-respiratory diseases.

For CEQA purposes, the SCAQMD considers a sensitive receptor to be a location where a sensitive individual could remain for 24 hours or longer, such as residences, hospitals, and schools (etc.), as described in the Localized Significance Threshold Methodology (SCAQMD 2008a, page 3-2). There are several sensitive land uses adjacent to the project site, including the following.

A project site location map, including sensitive receptor locations, is provided in Exhibit A.

Receptor-1 Existing residential land uses located to the west of the proposed project site. The nearest residential home located at Receptor-1 (marked as circle “1” on Exhibit A) is located approximately 80 feet (~24 meters) west of the project site’s western boundary.

For conservative localized analysis purposes, sensitive receptors are considered to be less than 25 meters from the project site.

1.4 Summary of Analysis Results
Table 1-2 provides a summary of the CEQA air quality impact analysis results.

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Table 1-2 | CEQA Air Quality Impact Criteria
Air Quality Impact Criteria Potentially
Significant
Potentially
Significant
Unless
Mitigated
Less Than
Significant No Impact
Would the project:
a) Conflict with, or obstruct the implementation of,
the applicable air quality plan? X
b) Result in a cumulatively considerable net
increase of any criteria pollutant for which the
project region is in non-attainment under an
applicable Federal or State ambient air quality
standard?
X
c) Expose sensitive receptors to substantial
pollutant concentrations? X
d) Result in other emissions (such as those leading
to odors) adversely affecting a substantial
number of people?
X
Table 1-3 provides a summary of the CEQA GHG impact criteria analysis results.

Table 1-3 | CEQA GHG Impact Criteria
Greenhouse Gas Impact Criteria Potentially
Significant
Potentially
Significant
Unless
Mitigated
Less Than
Significant No Impact
Would the project:
a) Generate greenhouse gas emissions, either
directly or indirectly, that may have a significant
impact on the environment?
X
b) Conflict with an applicable plan, policy, or
regulation adopted for the purpose of reducing
emissions of greenhouse gases?
X
Table 1-4 provides a summary of the CEQA energy impact criteria analysis results.

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Table 1-4 | CEQA Energy Impact Criteria
Energy Impact Criteria Potentially
Significant
Potentially
Significant
Unless
Mitigated
Less Than
Significant No Impact
Would the project:
a) Result in a potentially significant environmental
impact due to wasteful, inefficient, or
unnecessary consumption of energy?
X
b) Conflict with or obstruct a State and/or local plan
for renewable energy or energy efficiency? X

Legend Exhibit A Location Map 3075-2024-30 TOLL BROTHERS LAGUNA HILLS TOWNHOME PROJECT AIR QUALITY, GREENHOUSE GAS, AND ENERGY IMPACT STUDY // CITY OF LAGUNA HILLS, CA N 1 1 = Sensitive Receptor Location = Project Site Boundary ENGINEERING GROUP INC.

Exhibit B Site Plan 3075-2024-30 TOLL BROTHERS LAGUNA HILLS TOWNHOME PROJECT AIR QUALITY, GREENHOUSE GAS, AND ENERGY IMPACT STUDY // CITY OF LAGUNA HILLS, CA ENGINEERING GROUP INC. N

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2.0 Air Quality Setting
The Federal Clean Air Act (§ 7602) defines air pollution as any agent or combination of such agents, including any physical, chemical, biological, or radioactive substance which is emitted into or otherwise enters the ambient air. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Air pollution can cause disease, allergies and death. It affects soil, water, crops, vegetation, manmade materials, animals, wildlife, weather, visibility, and climate. It can also cause damage to and deterioration of property, present hazards to transportation, and negatively impact the economy.

This section provides background information on criteria air pollutants, the applicable federal, state and local regulations concerning air pollution, and the existing physical setting of the project within the context of local air quality.

2.1 Description of Air Pollutants
The following section describes the air pollutants of concern related to the project. Criteria air pollutants are defined as those pollutants for which the federal and state governments have established air quality standards for outdoor or ambient concentrations to protect public health. The following descriptions of criteria air pollutants have been provided by the SCAQMD. • Carbon Monoxide (CO) is a colorless, odorless, toxic gas produced by incomplete combustion of carbon-containing fuels (e.g., gasoline, diesel fuel, and biomass). Sources include motor vehicle exhaust, industrial processes (metals processing and chemical manufacturing), residential wood burning, and natural sources. CO is somewhat soluble in water; therefore, rainfall and fog can suppress CO conditions. CO enters the body through the lungs, dissolves in the blood, and competes with oxygen, often replacing it in the blood, thus reducing the blood's ability to transport oxygen to vital organs in the body. The ambient air quality standard for carbon monoxide is intended to protect persons whose medical condition already compromises their circulatory system's ability to deliver oxygen.

These medical conditions include certain heart ailments, chronic lung diseases, and anemia. Persons with these conditions have reduced exercise capacity even when exposed to relatively low levels of CO. Fetuses are at risk because their blood has an even greater affinity to bind with CO. Smokers are also at risk from ambient CO levels because smoking increases the background level of CO in their blood. The South Coast Basin has achieved attainment status for carbon monoxide by both USEPA and CARB. • Nitrogen Dioxide (NO2) is a byproduct of fuel combustion. The principal form of nitrogen oxide produced by combustion is nitric oxide (NO), but NO reacts quickly to form NO2, creating the mixture of NO and NO2 commonly called NOx. NO2 acts as an acute irritant and, in equal concentrations, is more injurious than NO. At atmospheric concentrations, however, NO2 is only potentially irritating. There is some indication of a relationship between NO2 and chronic pulmonary fibrosis. Some increase in bronchitis in young

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children has also been observed at concentrations below 0.3 parts per million (ppm). NO2 absorbs blue light which results in a brownish red cast to the atmosphere and reduced visibility. Although NO2 concentrations have not exceeded national standards since 1991 and the state hourly standard since 1993, NOx emissions remain of concern because of their contribution to the formation of O3 and particulate matter. • Ozone (O3) is one of a number of substances called photochemical oxidants that are formed when volatile organic compounds (VOC) and NOx react in the presence of ultraviolet sunlight. O3 concentrations in the South Coast basin are typically among the highest in the nation, and the damaging effects of photochemical smog, which is a popular name for a number of oxidants in combination, are generally related to the concentrations of O3.

Individuals exercising outdoors, children, and people with preexisting lung disease, such as asthma and chronic pulmonary lung disease, are considered to be the subgroups most susceptible to O3 effects. Short-term exposures (lasting for a few hours) to O3 at levels typically observed in southern California can result in breathing pattern changes, reduction of breathing capacity, increased susceptibility to infections, inflammation of the lung tissue, and some immunological changes. In recent years, a correlation between elevated ambient O3 levels and increases in daily hospital admission rates, as well as mortality, has also been reported. The South Coast Air Basin is designated by the USEPA as an extreme nonattainment area for ozone. Although O3 concentrations have declined substantially since the early 1990s, the South Coast basin continues to have peak O3 levels that exceed both state and federal standards.
• Fine Particulate Matter (PM10) consists of extremely small suspended particles or droplets 10 microns or smaller in diameter that can lodge in the lungs, contributing to respiratory problems. PM10 arises from such sources as re-entrained road dust, diesel soot, combustion products, tire and brake abrasion, construction operations, and fires. It is also formed in the atmosphere from NOx and SO2 reactions with ammonia. PM10 scatters light and significantly reduces visibility. Inhalable particulates pose a serious health hazard, alone or in combination with other pollutants. More than half of the smallest particles inhaled will be deposited in the lungs and can cause permanent lung damage. Inhalable particulates can also have a damaging effect on health by interfering with the body’s mechanism for clearing the respiratory tract or by acting as a carrier of an absorbed toxic substance. The South Coast basin has recently achieved federal attainment status for PM10, but is non-attainment based on state requirements.
• Ultra-Fine Particulate Matter (PM2.5) is defined as particulate matter with a diameter less than 2.5 microns and is a subset of PM10. PM2.5 consists mostly of products from the reaction of NOx and SO2 with ammonia, secondary organics, finer dust particles, and the combustion of fuels, including diesel soot. PM2.5 can cause exacerbation of symptoms in sensitive patients with respiratory or cardiovascular disease, declines in pulmonary function growth in children, and increased risk of premature death from heart or lung diseases in the elderly.

Daily fluctuations in PM2.5 levels have been related to hospital admissions for acute

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respiratory conditions, school absences, and increased medication use in children and adults with asthma. The South Coast basin is designated as non-attainment for PM2.5 by both federal and state standards.
• Sulfur Dioxide (SO2) is a colorless, pungent gas formed primarily by the combustion of sulfur-containing fossil fuels. Health effects include acute respiratory symptoms and difficulty in breathing for children. Individuals with asthma may experience constriction of airways with exposure to SO2. Though SO2 concentrations have been reduced to levels well below state and federal standards, further reductions in SO2 emissions are needed because SO2 is a precursor to sulfate and PM10. The South Coast basin is considered a SO2 attainment area by USEPA and CARB.
• Lead (Pb) is a toxic heavy metal that can be emitted into the air through some industrial processes, burning of leaded gasoline and past use of lead-based consumer products.

Lead is a neurotoxin that accumulates in soft tissues and bones, damages the nervous system, and causes blood disorders. It is particularly problematic in children, in that permanent brain damage may result, even if blood levels are promptly normalized with treatment. Concentrations of lead once exceeded the state and federal air quality standards by a wide margin, but as a result of the removal of lead from motor vehicle gasoline, ambient air quality standards for lead have not been exceeded since 1982.

Though special monitoring sites immediately downwind of lead sources recorded localized violations of the state standard in 1994, no violations have been recorded since.

Consequently, the South Coast basin is designated as an attainment area for lead by both the USEPA and CARB. This report does not analyze lead emissions from the project, as it is not expected to emit lead in any significant measurable quantity. • Volatile Organic Compounds (VOCs), although not actually a criteria air pollutant, VOCs are regulated by the SCAQMD because they cause chemical reactions which contribute to the formation of ozone. VOCs are also transformed into organic aerosols in the atmosphere, contributing to higher PM10 and lower visibility levels. Sources of VOCs include combustion engines, and evaporative emissions associated with fuel, paints and solvents, asphalt paving, and the use of household consumer products such as aerosols.

Although health-based standards have not been established for VOCs, health effects can occur from exposures to high concentrations of VOC. Some hydrocarbon components classified as VOC emissions are hazardous air pollutants. Benzene, for example, is a hydrocarbon component of VOC emissions that are known to be a human carcinogen. The term reactive organic gases (ROG) are often used interchangeably with VOC. • Toxic Air Contaminants (TACs) are defined as air pollutants that may cause or contribute to an increase in mortality or serious illness, or that may pose a present or potential hazard to human health (Health & Safety Code §39655). Unlike criteria pollutants, which have concentration-based standards, TACs generally do not have identified safe exposure levels. Per Cal. Code Regs., tit. 17, §93000, the California Air Resources Board (CARB) lists

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substances designated as TACs and specifies “None identified” for threshold levels when there is insufficient scientific evidence to establish a concentration below which adverse health effects are not expected to occur. The majority of the estimated health risk from TACs can be attributed to a relatively few compounds, the most common being diesel particulate matter (DPM) from diesel engine exhaust. In addition to DPM, benzene and 1,3- butadiene are also significant contributors to overall ambient public health risk in California.

2.2 Federal and State Ambient Air Quality Standards
The Federal Clean Air Act, which was last amended in 1990, requires the EPA to set National Ambient Air Quality Standards (NAAQS) for criteria pollutants considered harmful to public health and the environment. The State of California has also established additional and more stringent California Ambient Air Quality Standards (CAAQS) in addition to the seven criteria pollutants designated by the federal government.

AAQS are designed to protect the health and welfare of the populace with a reasonable margin of safety. The standards are divided into two categories, primary standards and secondary standards.

Primary standards are implemented to provide protection for the “sensitive” populations such as those with asthma, or the children and elderly. Secondary standards are to provide protection against visible pollution as well as damage to the surrounding environment, including animals, crops, and buildings.

Table 2-1 shows the Federal and State Ambient Air Quality Standards.

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Table 2-1 | Federal and State Ambient Air Quality Standards (AAQS)1 Air Pollutant Averaging Time2 Federal Standard
(NAAQS)2
California Standard
(CAAQS)2
Ozone
1 Hour -- 0.09 ppm
8 Hour 0.07 ppm 0.07 ppm
Carbon Monoxide
(CO)
1 Hour 35 ppm 20 ppm
8 Hour 9 ppm 9 ppm
Nitrogen Dioxide
(NO2)
1 Hour 0.100 ppm 0.18 ppm
Annual 0.053 ppm 0.030 ppm
Sulfur Dioxide
(SO2)
1 Hour 0.075 ppm 0.25 ppm
3 Hour 0.5 ppm3 --
24 Hour 0.14 ppm 0.04 ppm
Fine Particulate Matter
(PM10)
24 Hour 150 µg/m3 50 µg/m3
Annual Mean -- 20 µg/m3
Ultra-Fine Particulate
Matter
(PM2.5)
24 Hour 35 µg/m3 --
Annual Mean 12.0 µg/m3 12.0 µg/m3
Lead
(Pb)
30 Day Average -- 1.5 µg/m3
Calendar Quarter 1.5 µg/m3 --
Rolling 3 Month Average 0.15 µg/m3 --
Visibility Reducing
Particles 8 Hour --

0.23/km extinction
coefficient
(10-mile visibility standard)
Sulfates 24 Hour -- 25 µg/m3
Hydrogen Sulfide 1 Hour -- 0.03 µg/m3
Vinyl Chloride 24 Hour -- 0.01 ppm
1 Source: CARB. https://ww2.arb.ca.gov/sites/default/files/2020-07/aaqs2.pdf. 2 ppm = parts per million of air by volume.
µg/m3
= micrograms per cubic meter.
3 Secondary standards.

Several pollutants listed in Table 2-1 are not addressed in this analysis. Lead is not included because the project is not anticipated to emit lead. Visibility-reducing particles are not explicitly addressed in this analysis because particulate matter is addressed. The project is not expected to generate or be

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exposed to vinyl chloride because proposed project uses do not utilize the chemical processes that create this pollutant and there are no such uses in the project vicinity. The proposed project is not expected to cause exposure to hydrogen sulfide because there are no project activities or processes that produce this compound. Hydrogen sulfide emissions are typically associated with petroleum refining, geothermal operations, or wastewater treatment, none of which are included in the proposed residential project.

2.3 Attainment Status
The Clean Air Act requires states to prepare a State Implementation Plan (SIP), a comprehensive regulatory framework that demonstrates how states will achieve and maintain the NAAQS. The California Air Resources Board (CARB) provides designations of attainment for air basins where AAQS are either met or exceeded. If the AAQS are met, the area is designated as being in “attainment”, if the air pollutant concentrations exceed the AAQS, then the area is designated as being “nonattainment”. If there is inadequate or inconclusive data to make a definitive attainment designation, the area is considered “unclassified.”
National nonattainment areas are further designated as marginal, moderate, serious, severe, or extreme as a function of deviation from standards. Each standard has a different definition, or ‘form’ of what constitutes attainment, based on specific air quality statistics. For example, the Federal 8-hour CO standard is not to be exceeded more than once per year; therefore, an area is in attainment of the CO standard if no more than one 8-hour ambient air monitoring values exceeds the threshold per year. In contrast, the federal annual PM2.5 standard is met if the three-year average of the annual average PM2.5 concentration is less than or equal to the standard.

When a state submits a request to the EPA to re-designate a nonattainment area to attainment, the Clean Air Act (CAA) section 175A(a) requires that the state (or states, if the area is a multi-state area) submit a maintenance plan ensuring the area can maintain the air quality standard for which the area is to be re-designated for at least 10 years following the effective date of re-designation. Table 2-2 lists the attainment status for the criteria pollutants in the South Coast Air Basin (SCAB).

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Table 2-2 | South Coast Air Basin Attainment Status1
Pollutant State Status National Status
Ozone Nonattainment Nonattainment
(Extreme)2
Carbon Monoxide Attainment Attainment
(Maintenance)
Nitrogen Dioxide Attainment Attainment
(Maintenance)
PM10 Nonattainment Attainment
(Maintenance)
PM2.5 Nonattainment Nonattainment
Lead Attainment Nonattainment
(Partial)3
1 Source: CARB. https://ww2.arb.ca.gov/resources/documents/maps-state-and-federal-area-designations. 2 8-Hour Ozone.
3 Partial Nonattainment designation for Los Angeles County portion of Basin only.

2.4 South Coast Air Quality Management District (SCAQMD) The agency responsible for air pollution control for the South Coast Air Basin (SCAB) is the South Coast Air Quality Management District (SCAQMD). SCAQMD is responsible for controlling emissions from stationary sources. SCAQMD maintains air quality monitoring stations throughout the SCAB.

SCAQMD, in coordination with the Southern California Association of Governments, is also responsible for developing, updating, and implementing the Air Quality Management Plan (AQMP) for the SCAB. An AQMP is a plan prepared and implemented by an air pollution district for a county or region designated as nonattainment of the federal and/or California ambient air quality standards.

The term nonattainment area is used to refer to an air basin where one or more ambient air quality standards are exceeded. The AQMP is incorporated into the SIP.

The latest version is the 2022 AQMP, adopted in December 2022. The 2022 AQMP is a regional blueprint for achieving the federal air quality standards and healthful air. While air quality has dramatically improved over the years, the SCAB still exceeds federal public health standards for both ozone and particulate matter (PM) and experiences some of the worst air pollution in the nation. The 2022 AQMP includes both stationary and mobile source strategies to ensure that rapidly approaching attainment deadlines are met, that public health is protected to the maximum extent feasible, and that the region is not faced with burdensome sanctions if the Plan is not approved or if the NAAQS are not met on time.

According to the 2022 AQMP, the most significant air quality challenge in the SCAB is to reduce nitrogen oxide (NOx) emissions sufficiently to meet the upcoming ozone standard deadlines. Based

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on the inventory and modeling results, the 2022 AQMP projects that 184 tons per day (tpd) of NOx will be emitted in the year 2037 as a result of continued implementation of already adopted regulatory actions (“baseline emissions”). The analysis suggests that in order to meet the ozone standard of 60 tpd, NOx emissions need to be reduced about 67 percent beyond the projected 2037 baseline emissions and about 83 percent below current levels1
.

2.4.1 SCAQMD Rules and Regulations
The SCAQMD establishes a program of rules and regulations to obtain attainment of the state and federal standards in conjunction with the AQMP. Several of the rules and regulations that may be applicable to this project include, but are not limited to, the following:
• SCAQMD Rule 402 prohibits a person from discharging from any source whatsoever such quantities of air contaminants or other material which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or which endanger the comfort, repose, health or safety of any such persons or the public, or which cause, or have a natural tendency to cause, injury or damage to business or property. • SCAQMD Rule 403 governs emissions of fugitive dust during construction and operation activities. Compliance with this rule is achieved through application of standard Best Management Practices, such as application of water or chemical stabilizers to disturbed soils, covering haul vehicles, restricting vehicle speeds on unpaved roads to 15 miles per hour, sweeping loose dirt from paved site access roadways, cessation of construction activity when winds exceed 25 mph, and establishing a permanent ground cover on finished sites.
• SCAQMD Rule 445 restricts wood burning devices from being installed into any new development and is intended to reduce the emissions of particulate matter for wood burning devices.
• SCAQMD Rule 1113 governs the sale, use, and manufacturing of architectural coating and limits the VOC content in paints and paint solvents. This rule regulates the VOC content of paints available during construction. Therefore, all paints and solvents used during construction and operation of project must comply with Rule 1113. • SCAQMD Rule 1143 governs the manufacture, sale, and use of paint thinners and solvents used in thinning of coating materials, cleaning of coating application equipment, and other solvent cleaning operations by limiting their VOC content. This rule regulates the VOC content of solvents used during construction. Solvents used during the construction phase must comply with this rule.
1 Source: South Coast Air Quality Management District. 2022 Air Quality Management Plan. Adopted December 2, 2022.

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• SCAQMD Rule 1186 limits the presence of fugitive dust on paved and unpaved roads and sets certification protocols and requirements for street sweepers that are under contract to provide sweeping services to any federal, state, county, agency, or special district such as water, air, sanitation, transit, or school district.

The proposed project would be required to comply with the above South Coast Air Quality Management District rules and regulations, as well as all applicable federal, state, regional, and local regulations related to air quality. In addition to SCAQMD rules and regulations, these requirements include state energy efficiency standards and local solid waste management regulations. The following list summarizes applicable regulatory compliance requirements for the project. The project actions listed below represent standard regulatory compliance obligations and are not considered mitigation measures.

1. During construction, the project will follow the SCAQMD rules and requirements for fugitive dust control, including the following:
• Pre-water active grading or trenching areas.
• Water all active construction areas as frequently as needed (at least twice daily) to prevent visible dust plumes from extending more than 100 feet. • Maintain a stabilized surface or apply dust suppressants to inactive areas, disturbed surfaces, staging areas, haul routes, and unpaved roads. • Limit on-site vehicle speeds to 15 mph on unpaved areas. • Maintain all haul trucks with covered loads and ≥6 inches of freeboard (CVC §23114). • Stabilize stockpiles with water or covers and restrict height if near occupied structures. • Use a gravel pad at egress points (minimum 30' x 50', 1" washed gravel, 6" depth), or alternatively a wheel shaker or wheel washing station.
• Remove track-out extending ≥25 feet onto public roadways immediately and clean daily.
• Suspend dust-generating activities and implement contingency measures during high wind events (wind gusts >25 mph).
• Re-vegetate or stabilize disturbed areas within 21 days of inactivity. • Limit construction vehicle traffic to designated haul routes only.

2. The project will utilize low-VOC or zero-VOC paints, coatings, and solvents consistent with the requirements of SCAQMD Rules 1113 and 1143.

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3. The project will comply with the mandatory requirements of the California Building Standards Code, Title 24, Part 6 (Energy Code) and Part 11 (CALGreen), including, but not limited to:
• Install low flow fixtures and toilets, water efficient irrigation systems, drought tolerant/native landscaping, and reduce the amount of turf. • Provide the necessary infrastructure to support electric vehicle charging. • Provide solar installations/solar readiness zones per the prescribed Energy Design Ratings.

4. The project will participate in local waste management recycling and composting programs.

2.5 Local Climate and Meteorology
The weather station closest to the project site is the National Weather Service Cooperative – Laguna Beach, CA (044647) station. Climatological data from the National Weather Service at this station is summarized in Table 2-3.

Table 2-3 | Meteorological Summary1
Month
Temperature (°F) Mean
Precipitation
Max. (inches) Min. Mean
January 65.1 43.0 54.1 2.43
February 66.1 44.1 55.1 2.77
March 67.1 45.8 56.5 2.01
April 69.0 48.4 58.7 0.98
May 70.9 53.0 62.0 0.25
June 73.1 56.1 64.6 0.10
July 76.5 59.3 67.9 0.03
August 78.1 59.6 68.9 0.07
September 77.5 58.2 67.9 0.26
October 74.5 53.7 64.1 0.47
November 70.4 47.5 59.0 1.24
December 66.1 43.4 54.8 1.92
Annual 71.2 51.0 61.1 12.52
1 Source: Western Regional Climate Center. Averages derived from measurements recorded between 1928 and 2016 at Laguna Beach, CA (044647).

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2.6 Local Air Quality
The air quality at any site is dependent on the regional air quality and local pollutant sources. Regional air quality is determined by the release of pollutants throughout the air basin.

The SCAQMD has divided the SCAB into fourteen general forecasting areas and thirty-eight Source Receptor Areas (SRAs) for monitoring and reporting local air quality. The SCAQMD provides daily reports of the current air quality conditions in each general forecast area and SRA. The monitoring areas provide a general representation of the local meteorological, terrain, and air quality conditions within the SCAB.

The project is located within the Coastal general forecasting area and Central Orange County Coastal air monitoring area (SRA-20). The SCAQMD has not published air quality monitoring data for SRA-20.

Therefore, pollutant data for the most recent three-year period is derived from the nearest adjacent stations available (i.e., Saddleback Valley/SRA-19 and Central Orange County/SRA-17). These pollutant levels were used to comprise a “background” for the project location and existing local air quality.

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Table 2-4 | Local Air Quality1
Air Pollutant
Location
Averaging
Time Item2 2021 2022 2023
Carbon
Monoxide
--
Saddleback
Valley
1 Hour
Max 1-Hour (ppm) 1.0 1.2 --
Exceeded State Standard (20 ppm) No No --
Exceeded National Standard (35 ppm) No No --
8 Hour
Max 8 Hour (ppm) 0.8 1.0 --
Days > State Standard (9 ppm) No No --
Days >National Standard (9 ppm) No No --
Ozone
--
Saddleback
Valley
1 Hour Max 1-Hour (ppm) 0.105 0.110 --
Days > State Standard (0.09 ppm) 2.0 1.0 --
8 Hour
Max 8 Hour (ppm) 0.081 0.088 --
Days > State Standard (0.070 ppm) 8 6 --
Days >National Standard (0.070 ppm) 8 5 --
Nitrogen
Dioxide
--
Central Orange
County
1 Hour Max 1-Hour (ppm) 0.067 0.053 0.051
Exceeded State Standard (0.18 ppm) No No No
Annual
Annual Average (ppm) 0.012 0.012 0.011
Exceeded State Standard (0.030 ppm) No No No
Exceeded National Standard (0.053 ppm) No No No
Sulfur Dioxide
--
Saddleback
Valley
1 Hour
Max 1 Hour (ppm) -- 0.0000 --
Exceeded State Standard (0.25 ppm) -- No --
Exceeded National Standard (0.075 ppm) -- No --
PM10
--
Saddleback
Valley
24 Hour
Max 24-Hour (µg/m³) 35 -- --
Days > State Standard (50 µg/m³) 0 -- --
Days >National Standard (150 µg/m³) 0 -- --
Annual Annual Average (µg/m³) 15.60 -- --
Exceeded State Standard (20 µg/m³) No -- --
PM2.5
--
Saddleback
Valley
24 Hour Max 24-Hour (µg/m³) 28.70 -- --
Days >National Standard (35 µg/m³) 0 -- --
Annual
Annual Average (µg/m³) 8.27 -- --
Exceeded State Standard (12 µg/m³) No -- --
Exceeded National Standard (15 µg/m³) No -- --
1 Source: https://www.aqmd.gov/home/air-quality/historical-air-quality-data/historical-data-by-year. 2 ppm = parts per million.
µg/m³ = micrograms per cubic meter.

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3.0 Global Climate Change Setting
Lead agencies must analyze direct and indirect GHG emissions from proposed projects. This includes emissions from construction, operations, transportation, energy use, waste, and water consumption.

Lead agencies must make a good faith effort to describe, calculate, or estimate GHG emissions (CEQA Guidelines § 15064.4).

3.1 Greenhouse Gases (GHGs)
Greenhouse gases include naturally occurring compounds such as carbon dioxide (CO2), methane (CH4), water vapor (H2O), and nitrous oxide (N2O), while others are synthetic. Man-made GHGs include the chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs), as well as sulfur hexafluoride (SF6). Different GHGs have different effects on the Earth's warming. GHGs differ from each other in their ability to absorb energy (their "radiative efficiency") and how long they stay in the atmosphere, also known as the "lifetime".

The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of CO2. The larger the GWP, the more that a given gas warms the Earth compared to CO2 over that time period. The time period usually used for GWPs is 100 years. GWPs provide a common unit of measure, which allows analysts to add up emissions estimates of different gases and allows policymakers to compare emissions reduction opportunities across sectors and gases.

Table 3-1 lists the 100-year GWP of GHGs from the Intergovernmental Panel on Climate Change (IPCC) fifth assessment report (AR5) and IPCC sixth (6th) assessment report (AR6).

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Table 3-1 | Global Warming Potential of Greenhouse Gases1, 2 Gas Name Formula
Lifetime
(Years) GWP
Carbon Dioxide CO2 -- 1
Methane
CH4 (Fossil Origin)
12 29.8
CH4 (Non-Fossil Origin) 27.2
Nitrous Oxide N2O 114 273
Sulphur Hexafluoride SF6 3200 23,500
Nitrogen Trifluoride NF3 740 16,100
Chlorofluorocarbon (CFC11) CFC-11 52 8,321
Hexafluoroethane (PFC116) C2F6 10,000 11,100
Octafluoropropane (PFC218) C3F8 2,600 8,900
Octafluorocyclobutane
(PFC-318) C4F8 3,200 9,540
Tetrafluoromethane (PFC14) CF4 50,000 5,301
Hydrofluorocarbon 125 HFC-125 29 3,170
Hydrofluorocarbon 134a HFC-134a 14 1,526
Hydrofluorocarbon 143a HFC-143a 52 4,800
Hydrofluorocarbon 152a HFC-152a 1 138
Hydrofluorocarbon 227ea HFC-227ea 34 3,350
Hydrofluorocarbon 23 HFC-23 270 12,400
Hydrofluorocarbon 236fa HFC-236fa 240 8,060
Hydrofluorocarbon 245fa HFC-245fa 8 858
Hydrofluorocarbon 32 HFC-32 5 771
Hydrofluorocarbon 365mfc HFC-365mfc 9 804
Hydrofluorocarbon 43-
10mee HFC-43-10mee 16 1,650
1 Source: IPCC Sixth Assessment Report (AR6).
https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Full_Report.pdf and https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf. 2 GWPs are used to convert GHG emission values to “carbon dioxide equivalent” (CO2e) units.

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3.2 GHG Regulatory Setting – State of California
The State of California has been a leader in climate change legislation and has passed numerous bills to reduce greenhouse gas emissions across all sectors of the economy. Some of the key climate legislation and regulation in the State include the following:
• Assembly Bill (AB) 32, California Global Warming Solutions Act of 2006. AB 32 set the stage for the State’s transition to a sustainable, low-carbon future. AB 32 was the first program in the country to take a comprehensive, long-term approach to addressing climate change.
• Senate Bill (SB) 375, Sustainable Communities & Climate Protection Act of 2008. SB 375 requires the Air Resources Board to develop regional greenhouse gas emission reduction targets for passenger vehicles GHG reduction targets for 2020 and 2035 for each region covered by the State's 18 metropolitan planning organizations. • Senate Bill (SB) 100, California Renewables Portfolio Standard Program. SB 100 established a landmark policy requiring renewable energy and zero-carbon resources supply 100 percent of electric retail sales to end-use customers by 2045. • California Building Standards Code – Title 24. The California Building Standards Code Title 24 Part 6 (Energy Code) and Title 24 Part 11 (CALGreen) requires multiple building provisions to reduce energy usage and GHG emissions and is updated on a triennial basis.

3.3 GHG Emissions Inventory
Table 3-2 shows the latest GHG emission inventories at the national, state, regional, and local levels.

Table 3-2 | GHG Emissions Inventory 1
United States
(2019)2
State of California
(2019)3
SCAG
(2020)4
6,558 MMTCO2e 418 MMTCO2e 216.4 MMTCO2e
1 MMTCO2e = million metric tons of carbon dioxide equivalents. 2 https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks. 3 SCAG – Regional GHG Inventory and Reference Case Projections, 1990 – 2035. May 30, 2012. http://www.scag.ca.gov/programs/Pages/GreenhouseGases.aspx.

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4.0 Modeling Parameters and Assumptions
The California Emissions Estimator Model Version 2022.1.1 (CalEEMod) was used to calculate criteria air pollutants and GHG emissions from the construction and operation of the project. CalEEMod is a statewide land use emissions computer model designed to provide a uniform platform for government agencies, land use planners, and environmental professionals to quantify criteria air pollutant and GHG emissions.

The model quantifies direct emissions from construction and operation activities (including vehicle use), as well as indirect emissions, such as GHG emissions from off-site energy generation, solid waste disposal, vegetation planting and/or removal, and water use. The model also identifies design standards to reduce criteria pollutant and GHG emissions. The model was developed for the California Air Pollution Control Officers Association (CAPCOA) in collaboration with the California air districts.

4.1 Construction Assumptions
Construction of the project is estimated to begin in the year 2026. Construction activities are expected to consist of demolition, site preparation, grading, building construction, paving, and architectural coating. The project will require the import and export of up to 35,000 total cubic yards of earthwork material for grading purposes. For the purposes of this analysis, construction phases are not expected to overlap.

The CalEEMod default construction equipment list is based on survey data and the size of the site. The parameters used to estimate construction emissions, such as the worker and vendor trips and trip lengths, utilize the CalEEMod defaults. The construction equipment list is shown in Table 4-1.

All mobile off-road diesel construction equipment including generators will be equipped with Tier 4 low emission “clean diesel” engines. Accordingly, the CalEEMod default construction equipment list was modified to reflect Tier 4 engines for applicable equipment.

The project will be required to comply with several standard fugitive dust control measures, per SCAQMD Rule 403. The following key inputs are utilized in CalEEMod and are based upon data provided from SCAQMD :
• Water exposed area – 61% PM10 and PM2.5 reduction.
• Water unpaved roads twice daily – 55% PM10 and PM2.5 reduction. • Limit vehicle speeds on unpaved roads to 25 mph – 44% PM10 and PM2.5 reduction. • Sweep paved roads once per month – 9% PM10 and PM2.5 reduction.

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Table 4-1 | Construction Equipment Assumptions 1
Phase Equipment Number Hours
Per Day
Soil
Disturbance
Rate
(Acres/8-
Hour Day)
Off-Road
Equipment
Daily
Disturbance
Footprint
(Acres)
Total Daily
Disturbance
Footprint
(Acres)
Demolition
Concrete/Industrial Saws 1 8 0.00 0.00
Rubber Tired Dozers 1 8 0.50 0.50 0.50
Tractors/Loaders/Backhoes 3 8 0.00 0.00
Site
Preparation
Graders 1 8 0.50 0.50
Scrapers 1 8 1.00 1.00 1.50
Tractors/Loaders/Backhoes 1 7 0.00 0.00
Grading
Graders 1 8 0.50 0.50
Rubber Tired Dozers 1 8 0.50 0.50 1.00
Tractors/Loaders/Backhoes 2 7 0.00 0.00
Building
Construction
Cranes 1 8 0.00 0.00

0.00 Forklifts 2 7 0.00 0.00
Generator Sets 1 8 0.00 0.00
Tractors/Loaders/Backhoes 1 6 0.00 0.00
Welders 3 8 0.00 0.00
Paving
Cement and Mortar Mixers 1 8 0.00 0.00

0.00 Pavers 1 8 0.00 0.00
Paving Equipment 1 8 0.00 0.00
Rollers 2 8 0.00 0.00
Tractors/Loaders/Backhoes 1 8 0.00 0.00
Architectural
Coating Air Compressors 1 6 0.00 0.00 0.00
1 CalEEMod defaults.

4.2 Localized Construction Analysis Modeling Parameters CalEEMod calculates construction emissions based on the number of equipment hours and the maximum daily disturbance activity possible for each piece of equipment. This report identifies the

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following parameters in the project design or applicable mitigation measures in order to compare CalEEMod reported emissions against the localized significance threshold lookup tables:

1. The off-road equipment list (including type of equipment, horsepower, and hours of operation) assumed for the day of construction activity with maximum emissions.

2. The maximum number of acres disturbed on the peak day.

3. Any emission control devices added onto off-road equipment.

4. Specific dust suppression techniques used on the day of construction activity with maximum emissions.

4.3 Operational Assumptions
Operational emissions occur over the life of the project and are considered “long-term” sources of emissions. Operational emissions include both direct and indirect sources. This section briefly describes the operational sources of emissions analyzed for the project.

4.3.1 Mobile Source Emissions
Mobile source emissions would be the largest source of long-term air pollutants from the proposed operation of the project. Mobile sources are direct sources of project emissions that are primarily attributed to tailpipe exhaust and road dust (tire, brake, clutch, and road surface wear) from motor vehicles traveling to and from the site.

Estimates of mobile source emissions require information on four parameters: trip generation, trip length, vehicle/fleet mix, and emission factors (quantity of emission for each mile traveled or time spent idling by each vehicle).

The trip generation rates used for this analysis are based on the Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition. The proposed project consists of constructing 36 townhome dwelling units. As such, ITE Land Use 215: Single-Family Attached Housing accurately reflect the proposed project land use. For trip lengths, the CalEEMod defaults are used.

The Emission Factors (EMFAC2021) 2021 model and off-model adjustments factors to account for the SAFE Vehicle Rule is used to estimate the mobile source emissions are embedded in the CalEEMod emissions model. No adjustments have been made to default emission factors.

The project’s total vehicle miles traveled is shown in Table 4-2.

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Table 4-2 | Operational Vehicle Miles Traveled 1
Land Use Annual Home-Based Vehicle Miles Traveled
(VMT)
Condo/Townhouse 905,531
1 CalEEMod defaults.

To be conservative, this analysis has assumed that 2% of the total trips associated with the project will be heavy trucks with a gross vehicle weight rating (GVWR) of 10,000 pounds or greater. This includes LHD2, MHD, HHD, OBUS, UBUS, and SBUS vehicles. This is conservative, as in practice, residential land uses such as the one proposed by the project typically generate very few heavy truck trips, generally less than 1% of total traffic. Using 2% therefore overestimates the proportion of heavy trucks associated with the project. The adjusted vehicle mix is proportioned according to the default CalEEMod vehicle mix.

Table 4-3 summarizes the adjusted vehicle mix used for the project.

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Table 4-3 | Operational Vehicle Mix 1
Vehicle Type Vehicle Mix
Light Duty Automobile (LDA) 50.42%
Light Duty Truck (LDTI) 4.13%
Light Duty Truck (LDT2) 23.72%
Medium Duty Truck (MDV) 14.70%
Light Heavy Truck (LHD1) 2.80%
Light Heavy Truck (LHD2) 0.42%
Medium Heavy Truck (MHD) 0.90%
Heavy Heavy Truck (HHD) 0.33%
Other Bus (OBUS) 0.04%
Urban Bus (UBUS) 0.04%
Motorcycle (MCY) 2.23%
School Bus (SBUS) 0.06%
Motor Home (MH) 0.22%
Total 100.00%
1 Adjusted fleet mix to include 2% total trucks over 10,000 lbs. GVWR (LHD2, MHD, HHD, OBUS, UBUS, SBUS, MH).

4.3.2 Energy Source Emissions
Energy usage includes both direct and indirect sources of emissions. Direct sources of emissions include on-site energy usage, while indirect emissions include electricity generated by offsite power plants. The proposed project will be powered exclusively by electricity, with no use of natural gas. As a result, this analysis evaluates all project-related energy consumption solely in terms of electricity usage.

CalEEMod divides building electricity use into uses that are subject to Title 24 standards and those that are not. Lighting electricity usage is also calculated as a separate category in CalEEMod. For electricity, Title 24 uses include the major building envelope systems covered by Part 6 (California Energy Code) of Title 24, such as space heating, space cooling, water heating, and ventilation. NonTitle 24 uses include all other end uses, such as appliances, electronics, and other miscellaneous plugin uses. Because some lighting is not considered as part of the building envelope energy budget, and since a separate mitigation measure is applicable to this end use, CalEEMod makes lighting a separate category.

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The baseline values are based on the California Energy Commission (CEC) sponsored California Commercial End Use Survey (CEUS) and Residential Appliance Saturation Survey (RASS) studies.

The project will be required to provide on-site renewable energy photovoltaic installations (solar panels), as prescribed by the 2022 Building Energy Efficiency Standards for Residential and Nonresidential Buildings.

In order to assess the potential project’s future energy usage, RK has performed a quantitative energy impact analysis using CEQA energy impact criteria. The energy impact analysis is provided in Section

8.0 of this report.

4.3.3 Area Source Emissions
Area source emissions are direct sources of emissions that fall under four categories: hearths, consumer products, architectural coatings, and landscaping equipment. Per SCAQMD Rule 445, no wood burning devices are allowed in new developments; therefore, no wood hearths are included in this project.

Consumer products are various solvents used in non-industrial applications which emit ROGs during their product use. These typically include cleaning supplies, kitchen aerosols, cosmetics, and toiletries.

4.3.4 Other Sources of Operational Emissions
• Water. Greenhouse gas emissions are generated from the upstream energy required to supply and treat the water used on the project site. Indirect emissions from water usage are counted as part of the project’s overall impact.
• Waste. CalEEMod calculates the indirect GHG emissions associated with waste that is disposed of at a landfill. The program uses annual waste disposal rates from the California Department of Resources Recycling and Recovery (CalRecycle) data for individual land uses. The program quantifies the GHG emissions associated with the decomposition of the waste which generates methane based on the total amount of degradable organic carbon.

The project’s estimated water usage and waste generation is reported in Table 4-4.

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Table 4-4 | Operational Water Usage and Waste Generation 1 Land Use
Water Usage
(gallons/yr) Waste Generation
(tons/yr) Indoor Outdoor Total
Condo/Townhouse 1,350,923.40 475,213.66 1,826,137.06 26.55 Parking Lot -- -- -- --
Total 1,350,923.40 475,213.66 1,826,137.06 26.55
1 CalEEMod defaults.

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5.0 Significance Thresholds

5.1 Air Quality Regional Significance Thresholds
The SCAQMD has established air quality emissions thresholds for criteria air pollutants for the purposes of determining whether a project may have a significant effect on the environment per Section 15002(g) of the Guidelines for implementing CEQA. By complying with the thresholds of significance, the project would be in compliance with the SCAQMD Air Quality Management Plan (AQMP) and the federal and state air quality standards.

Table 5-1 lists the air quality significance thresholds for the six air pollutants analyzed in this report.

Lead is not included as part of this analysis as the project is not expected to emit lead in any significant measurable quantity.

Table 5-1 | SCAQMD Regional Significance Thresholds1
Pollutant Construction
(lbs/day)
Operation
(lbs/day)
NOX 100 55
VOC 75 55
PM10 150 150
PM2.5 55 55
SOX 150 150
CO 550 550
1 Source: http://www.aqmd.gov/docs/default-source/ceqa/handbook/scaqmd-air-quality-significance-thresholds.pdf.

5.2 Air Quality Localized Significance Thresholds
Air quality emissions were analyzed using the SCAQMD’s Mass Rate Localized Significance Threshold (LST) Look-up Tables.

Table 5-2 lists the Localized Significance Thresholds (LST) used to determine whether a project may generate significant adverse localized air quality impacts. LSTs represent the maximum emissions from a project that are not expected to cause or contribute to an exceedance of the most stringent applicable federal or state ambient air quality standard at the nearest sensitive receptors in the project vicinity. LSTs are developed based on the ambient concentrations of four applicable air pollutants for SRA-20 (Central Orange County Coastal).

The nearest existing sensitive receptors are located to the west of the project site, less than 25 meters from potential areas of on-site construction and operational activity. Although receptors are located

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closer than 25 meters to the site, SCAQMD LST methodology states that projects with boundaries located closer than 25 meters to the nearest receptor should use the LSTs for receptors located at 25 meters.

The disturbance area for applying SCAQMD LST thresholds is based on the maximum area of active ground disturbance that could occur at one time during construction, as this represents the largest potential source area for localized emissions. As shown in Table 4-1, the daily disturbance area is calculated to be 1.5 acres, however LST thresholds are only based on 1, 2, and 5-acre sites. To be conservative, a linear trend was used to estimate the construction thresholds for 1.5-acre sites based on the established LST thresholds.

Table 5-2 | SCAQMD Localized Significance Thresholds (LSTs)1 Pollutant Construction
(lbs/day)
Operation
(lbs/day)
NOX 110.5 110.5
CO 800.7 800.7
PM10 5.5 1.5
PM2.5 4.0 1.4
1 Source: SCAQMD Mass Rate Localized Significance Thresholds for 1.5 acres/day in SRA-20 at 25 meters.

5.3 GHG Significance Thresholds

5.3.1 SCAQMD GHG Interim Significance Thresholds
The SCAQMD has published the Interim CEQA Greenhouse Gas (GHG) Significance Thresholds, December 2008, to assist local agencies with determining the impact of a project’s GHG emissions.

SCAQMD’s objective in providing the GHG guidelines is to establish a performance standard that will ultimately contribute to reducing GHG emissions below 1990 levels, and thus achieve the requirements of the California Global Warming Solutions Act (AB 32). The SCAQMD’s GHG thresholds were upheld in Upland Community First v. City of Upland (2024) 105 Cal. App. 5th 1, 20.

In the absence of a formal threshold established by the State, SCAQMD’s interim GHG threshold has been established for use by lead agencies in determining significance of GHG emissions in CEQA.

SCAQMD guidance describes a five-tiered approach for determining significance. Tier 3 is the primary method used for development projects of this size and is the approach used in this analysis. The Tier 3 approach limits the amount of GHG emissions from residential and commercial development projects to 3,000 metric tons of CO2 equivalents per year (MTCO2e/yr).

If the project exceeds 3,000 MTCO2e/yr, then the impact is considered significant, and mitigation measures would be required to reduce emissions below the threshold.

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6.0 Air Quality Impact Analysis

6.1 Short-Term Air Quality Impacts – Construction

6.1.1 Regional Emissions – Construction
Regional air quality emissions include both on-site and off-site emissions associated with construction of the project. As shown in Table 6-1, the project’s potential regional daily emissions of criteria pollutants are expected to be below the allowable thresholds of significance.

CalEEMod emissions outputs are provided in Appendix A.

Table 6-1 | Regional Construction Emissions
Activity
Maximum Daily Emissions
(lbs./day)1
VOC NOX CO SO2 PM10 PM2.5
Demolition 0.48 6.95 17.08 0.05 4.02 0.84
Site Preparation 0.28 1.36 15.39 0.03 0.77 0.14
Grading 0.97 63.00 41.32 0.36 16.90 5.77
Building Construction 0.33 3.96 14.19 0.02 0.41 0.13
Paving 0.47 2.23 9.28 0.01 0.23 0.08
Architectural Coating 46.58 0.85 1.35 0.00 0.09 0.03
Maximum1 46.58 63.00 41.32 0.36 16.90 5.77
SCAQMD Threshold 75 100 550 150 150 55
Exceeds Threshold? No No No No No No
1 Maximum daily emissions during summer or winter; includes both onsite and offsite project emissions.

The project must follow mandatory SCAQMD rules and requirements with regards to fugitive dust control, as described in Section 6.1.3.

Table 6-1 shows that the project’s potential daily construction emissions would be below the applicable SCAQMD air quality standards and thresholds of significance. As a result, the project would not contribute substantially to an existing or projected air quality violation.

Furthermore, by complying with the SCAQMD standards, the project would not contribute to a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under an applicable Federal or State ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors).

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Therefore, the project’s short-term construction impact on regional air resources will be less than significant.

6.1.2 Localized Emissions – Construction
Table 6-2 illustrates the construction-related localized emissions and compares the results to SCAQMD LST thresholds. As shown in Table 6-2, the emissions will be below the SCAQMD thresholds of significance for localized construction emissions. The project must follow all standard SCAQMD rules and requirements with regards to fugitive dust control, as described in Section 6.1.3.

Therefore, the project’s short-term construction impact on localized air quality would be less than significant.

Table 6-2 | Localized Construction Emissions
Activity
Maximum Daily Emissions
(lbs./day)1
NOX CO PM10 PM2.5
Onsite Emissions 3.74 15.05 2.93 1.40
SCAQMD Localized Threshold2 110.5 800.7 5.5 4.0
Exceeds Threshold? No No No No
1 Maximum daily emissions during summer or winter; includes both onsite and offsite project emissions. 2 Source: SCAQMD Mass Rate Localized Significance Thresholds for 1.5 acres/day in SRA-20 at 25 meters.

6.1.3 Fugitive Dust – Construction
The Project is required to comply with standard SCAQMD rules that assist in reducing short-term air pollutant emissions associated with suspended particulate matter, also known as fugitive dust.

Fugitive dust emissions are commonly associated with land clearing activities, cut-and-fill grading operations, and exposure of soils to the air and wind. SCAQMD Rule 403 requires that fugitive dust is controlled with best-available control measures so that the presence of such dust does not remain visible in the atmosphere beyond the property line of the emission source. In addition, SCAQMD Rules 402 and 403 require implementation of dust suppression techniques to prevent fugitive dust from creating a nuisance off site.

6.1.4 Odors – Construction
Heavy-duty equipment in the project area during construction will emit odors; however, the construction activity would cease to occur after individual construction is completed. The project is required to comply with Rule 402 during construction, which states that a person shall not discharge from any source whatsoever such quantities of air contaminants or other material which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or which

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endanger the comfort, repose, health or safety of any such persons or the public, or which cause, or have a natural tendency to cause, injury or damage to business or property. No other sources of objectionable odors have been identified for the proposed Project.

Therefore, the project impact from odor emissions would be less than significant.

6.1.5 Asbestos – Construction
Asbestos is a carcinogen and is categorized as a hazardous air pollutant by the Environmental Protection Agency (EPA) and regulated through the National Emissions Standards for Hazardous Air Pollutants (NESHAP). Asbestos fibers embedded within construction materials become a health hazard once they are disturbed and rendered airborne, such as through physical contact like building renovation and demolition activities.

SCAQMD is the local enforcement authority for asbestos. SCAQMD Rule 1403 establishes the survey requirements, notification, and work practices to prevent asbestos emissions from emanating during building renovation and demolition activities. The project proposes to demolish the existing building and hardscape on the project site during construction. Compliance with Rule 1403 will ensure that the project does not result in asbestos emissions that would adversely affect a substantial number of people.

Asbestos also occurs naturally in serpentine and ultramafic rock. Based on the California Division of Mines and Geology General Location Guide for Ultramafic Rocks in California - Areas More Likely to Contain Naturally Occurring Asbestos, naturally occurring asbestos has not been shown to occur within in the vicinity of the project site. Therefore, the potential risk for naturally occurring asbestos (NOA) during project construction is small. However, in the event NOA is found on the site, the project will be required to comply with SCAQMD and NESHAP standards.

By following the SCAQMD’s required asbestos abatement protocols, the project impact would be less than significant.

6.1.6 Diesel Particulate Matter – Construction
The project will generate diesel particulate matter (DPM) during construction from off-road diesel equipment and trucks. The California Office of Environmental Health Hazard Assessment (OEHHA) adopted the Guidance Manual for Preparation of Health Risk Assessments (HRA Guidelines) to provide procedures for use in the Air Toxics Hot Spots Program or for the permitting of existing, new, or modified stationary sources2
.
2 OEHHA. Air Toxics Hot Spots Program. Risk Assessment Guidelines. Guidance for Preparation of Health Risk Assessments. February 2015.

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To evaluate potential cancer and non-cancer health risks associated with DPM emissions during project construction, RK prepared the Toll Brothers Laguna Hills Townhome Project Construction Health Risk Assessment (HRA). Construction-related PM10 exhaust emissions were quantified using the CalEEMod outputs provided in Appendix A and used as a surrogate for modeling DPM emissions.

The HRA indicates that the project will not exceed the applicable cancer and non-cancer health risk thresholds established by the SCAQMD.

As a result, the project’s short-term construction health risk impact would be less than significant.

6.2 Long-Term Air Quality Impacts – Operation

6.2.1 Regional Emissions – Operation
Long-term unmitigated operational air pollutant impacts from the project are shown in Table 6-3.

CalEEMod emissions outputs are provided in Appendix A.

The project’s daily unmitigated operational emissions will be below the applicable SCAQMD regional air quality standards and thresholds of significance, and the project would not contribute substantially to an existing or projected air quality violation. Furthermore, by complying with the SCAQMD standards, the project would not contribute to 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 (including releasing emissions which exceed quantitative thresholds for ozone precursors).

Therefore, the project’s long-term regional air quality impacts would be less than significant.

Table 6-3 | Regional Operational Emissions
Activity
Maximum Daily Emissions
(lbs./day)1
VOC NOX CO SO2 PM10 PM2.5
Mobile Sources 0.97 0.71 8.49 0.02 2.08 0.54
Area Sources 1.86 0.02 2.04 0.00 0.00 0.00
Energy Sources 0.01 0.22 0.09 0.00 0.02 0.02
Total 2.84 0.95 10.62 0.02 2.10 0.55
SCAQMD Threshold 55 55 550 150 150 55
Exceeds Threshold? No No No No No No
1 Maximum daily emissions during summer or winter; includes both onsite and offsite project emissions.

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6.2.2 Localized Emissions – Operations
Table 6-4 shows the localized operational emissions and compares the results to SCAQMD LST thresholds of significance. As shown in Table 6-4, the emissions will be below the SCAQMD thresholds of significance for localized operational emissions.

Therefore, the project’s long-term localized air quality impacts would be less than significant.

Table 6-4 | Localized Operational Emissions
Activity
Maximum Daily Emissions
(lbs./day)1
NOX CO PM10 PM2.5
Onsite Emissions 0.27 2.56 0.12 0.05
SCAQMD Localized Threshold2 110.5 800.7 1.5 1.4
Exceeds Threshold? No No No No
1 Maximum daily emissions during summer or winter.
2 Source: SCAQMD Mass Rate Localized Significance Thresholds for 1.5 acres/day in SRA-20 at 25 meters.

6.2.3 Odors – Operation
Land uses that commonly receive odor complaints include agricultural uses (farming and livestock), chemical plants, composting operations, dairies, fiberglass molding facilities, food processing plants, landfills, refineries, rail yards, and wastewater treatment plants. The proposed residential project does not contain land uses that would typically be associated with significant odor emissions.

The project will be required to comply with standard building code requirements related to exhaust ventilation, as well as comply with SCAQMD Rule 402. Rule 402 requires that a person may not discharge from any source whatsoever such quantities of air contaminants or other material which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or which endanger the comfort, repose, health or safety of any such persons or the public, or which cause, or have a natural tendency to cause, injury or damage to business or property. Project related odors would not create a nuisance.

Therefore, the project’s operation would result in less than significant odor impacts.

6.2.4 Toxic Air Contaminants – Operations
The proposed project consists of residential land use and does not include major sources of toxic air contaminants (TAC) emissions that would result in significant exposure of sensitive receptors to substantial pollutant concentrations. Examples of land uses that are major sources of TACs include distribution centers with heavy truck traffic, rail yards, ports, refineries, chrome plating facilities, dry

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cleaners, and gasoline dispensing stations. The project does not include any of these uses, hence the project’s potential impact is considered less than significant.

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7.0 Greenhouse Gas Impact Analysis

7.1 Greenhouse Gas Emissions – Construction
Greenhouse gas emissions are estimated for on-site and off-site construction activity using CalEEMod.

Table 7-1 shows the construction greenhouse gas emissions, including equipment and worker vehicle emissions for all phases of construction.

CalEEMod GHG output calculations are provided in Appendix A.

Table 7-1 | Construction Greenhouse Gas Emissions
Activity
Emissions
(MTCO2e)1
Onsite Offsite Total
Demolition 22.70 34.67 57.37
Site Preparation 3.71 0.13 3.84
Grading 6.70 143.15 149.85
Building Construction 221.10 45.60 266.71
Paving 5.66 0.85 6.51
Architectural Coating 0.61 0.29 0.90
Total 260.48 224.69 485.18
Amortized Over 30 Years2 8.68 7.49 16.17
1 MTCO2e = metric tons of carbon dioxide equivalents (includes carbon dioxide, methane, nitrous oxide, and/or hydrofluorocarbons).
2 The emissions are amortized over 30 years and added to the operational emissions, pursuant to SCAQMD recommendations.

Because impacts from construction activities occur over a relatively short period of time, they contribute a relatively small portion of the overall lifetime project GHG emissions. Therefore, the SCAQMD recommends amortizing construction GHG emissions over a 30-year project lifetime and adding them to the overall project operational emissions. Pursuant to SCAQMD recommendations, this study assesses construction related GHG emissions along with the project’s operational emissions, as further discussed in the section below.

7.2 Greenhouse Gas Emissions – Operations
Greenhouse gas emissions are estimated for on-site and off-site operational activity using CalEEMod.

Table 7-2 shows the project’s operational greenhouse gas emissions, along with the project’s amortized construction emissions.

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Appendix A provides the CalEEMod emissions outputs for this study.

Table 7-2 | Operational Greenhouse Gas Emissions
Emission Source Unmitigated GHG Emissions
(MTCO2e/yr.)1
Mobile Sources 297.27
Area Sources 2.98
Energy Sources 94.58
Water 4.68
Waste 8.29
Refrigerant 0.09
Construction (30-Year Amortization) 16.17
Total Annual Emissions 424.06
SCAQMD Tier 3 Significance Threshold 3,000.00
Exceeds Threshold? No
1 MTCO2e/yr. = metric tons of carbon dioxide equivalents per year.

As shown in Table 7-2, the proposed project’s GHG emissions are not expected to exceed the SCAQMD GHG emissions threshold of 3,000 MTCO2e.

Therefore, the proposed project’s impact from GHG emissions would be less than significant.

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8.0 Energy Impact Analysis

8.1 Study Objectives
The purpose of this energy conservation analysis is to review the energy implications of the proposed project and provide recommendations to reduce wasteful, inefficient, and unnecessary consumption of energy during the operation of the project. This analysis has been prepared within the context of the California Environmental Quality Act (CEQA, California Public Resources Code Sections 21000, et seq.).

CEQA Guidelines, Appendix F, Energy Conservation, describes the framework within which energy conservation should be analyzed. Conserving energy implies the wise and efficient use of energy through decreasing overall per capita energy consumption, decreasing reliance on fossil fuels (such as coal, natural gas, and oil), and increasing reliance on renewable energy sources.

8.2 Utility Providers
The proposed project would be served by the utility providers shown in Table 8-1 below.

Table 8-1 | Utility Providers
Utility Provider
Electricity Southern California Edison
Natural Gas Southern California Gas Company

8.3 Project Energy Consumption
The three (3) main types of energy expected to be consumed by the project include electricity, natural gas, and petroleum products in the form of gasoline and diesel fuel. CalEEMod is used to calculate energy usage associated with the construction and operation of the project.

The CalEEMod calculation sheets for the project are provided in Appendix A. The EMFAC2021 vehicle fuel consumption data used for this analysis is provided in Appendix B.

8.3.1 Electricity Consumption
The project will use electricity for operational activities including, but not limited to, building heating and cooling, lighting, appliances, electronics, mechanical equipment, and parking lot lighting.

Indirect electricity usage will also be required to supply, distribute, and treat water and wastewater.

Electricity will be provided to the site by Southern California Edison.

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Temporary electricity usage for construction activities may include lighting, electric equipment, and mobile office uses. However, CalEEMod does not calculate electricity usage during construction.

Electricity usage during construction is expected to be short-term and relatively minor compared to the operational demand.

Table 8-2 shows the project’s estimated operational electricity consumption in kilowatt-hours per year (kWh/yr) and millions of BTU per year (MMBTU/yr).

Table 8-2 | Project Electricity Consumption1
Land Use/Activity
Electricity Consumption
(KWh/yr.)2 (MMBTU/yr.)2
Condo/Townhouse 167,260.09 570.69
Parking Lot 35,105.88 119.78
Water Supply and Treatment 12,430.51 42.41
Total 214,796.48 732.88
1 CalEEMod defaults.
2 KWHr/yr. = kilowatt hours per year.

MMBTU/yr. = million British Thermal Units per year.

8.3.2 Natural Gas Consumption
The proposed project will be powered exclusively by electricity, with no use of natural gas. As a result, all project-related energy usage is accounted for in the projected electricity consumption shown in Table 8-2.

8.3.3 Petroleum Consumption
The project’s energy consumption from petroleum products is primarily associated with transportation-related activities. This includes gasoline and diesel fuel usage for auto and truck trips during construction and operation and off-road equipment usage during construction.

8.3.3.1 Petroleum Consumption – Construction
Construction of the project is expected to consist of demolition, site preparation, grading, building construction, paving, and architectural coating phases. Construction activities will consume energy in the form of motor vehicle fuel (gasoline and diesel) for off-road construction equipment and on-road vehicle trips. Vehicle trips include workers and vendors traveling to and from the project site.

Table 8-3 and Table 8-4 show the project’s energy consumption for all off-road and on-road equipment during construction, respectively. For the purposes of this analysis, all off-road equipment is assumed to run on diesel fuel.

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Table 8-3 | Construction Off-Road Equipment Energy Consumption Phase1 Phase Duration (Days)1 Equipment1 Amount1 Hrs./Day1 Horsepower (HP)1 Load Factor1 HP-hrs.2 Fuel
Consumption
Rate
(HP-hrs./gal.)3
Diesel Fuel
Consumption
(Gal.)
Diesel Fuel
Consumption
by Phase
(Gal.)
MMBTU4
Demolition 20
Concrete/Industrial Saws 1 8 33 0.73 3,854.40

18.50 208.35
Rubber Tired Dozers 1 8 367 0.40 23,488.00 1,269.62 2,284.37 313.83 Tractors/Loaders/Backhoes 3 8 84 0.37 14,918.40 806.40
Site Preparation 3
Graders 1 8 148 0.41 1,456.32 78.72
Scrapers 1 8 423 0.48 4,872.96 263.40 377.40 51.85
Tractors/Loaders/Backhoes 1 7 84 0.37 652.68 35.28
Grading 6
Graders 1 8 148 0.41 2,912.64 157.44
Rubber Tired Dozers 1 8 367 0.40 7,046.40 380.89 679.45 93.34 Tractors/Loaders/Backhoes 2 7 84 0.37 2,610.72 141.12
Building Construction 220
Cranes 1 8 367 0.29 187,316.80 10,125.23
21,966.70 3,017.81
Forklifts 2 7 82 0.20 50,512.00 2,730.38
Generator Sets 1 8 14 0.74 18,233.60 985.60
Tractors/Loaders/Backhoes 1 6 84 0.37 41,025.60 2,217.60 Welders 3 8 46 0.45 109,296.00 5,907.89
Paving 10
Cement and Mortar Mixers 1 8 10 0.56 448.00 24.22
562.59 77.29
Pavers 1 8 81 0.42 2,721.60 147.11
Paving Equipment 1 8 89 0.36 2,563.20 138.55
Rollers 2 8 36 0.38 2,188.80 118.31
Tractors/Loaders/Backhoes 1 8 84 0.37 2,486.40 134.40
Architectural Coating 10 Air Compressors 1 6 37 0.48 1,065.60 57.60 57.60 7.91 Total Energy Requirements 25,928.11 3,562.03
1 CalEEMod defaults. 2 HP-hrs. = Horsepower hours. 3 Source: Carl Moyer Program Guidelines. 2017 Revisions. Table D-21. https://www.arb.ca.gov/msprog/moyer/guidelines/current.htm.4 MMBTU = Millions of BTU, assuming 1 gallon of diesel fuel = 137,381 BTU.

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Table 8-4 | Construction On-Road Equipment Energy Consumption Phase1
Phase
Duration
(Days)1
Trips per
Day1
Trip
Length
Phase
VMT
Vehicle
Class1
Vehicle
Mix1
Average
Fuel
Economy
(MPG)2
Gasoline Diesel
Total
MMBTU3 Fuel Split2
Fuel Consumption
by Vehicle Class
(Gal.)
Fuel Consumption
by Phase
(Gal.)
Fuel Split2
Fuel Consumption
by Vehicle Class
(Gal.)
Fuel Consumption
by Phase
(Gal.)
Worker Trips
Demolition 20 13 18.5 4,810
LDA 0.50 29.94 0.9986 80.20
177.28

0.0014 0.11
LDT1 0.25 24.89 0.9998 48.31 0.0002 0.01 0.25 21.38 LDT2 0.25 24.59 0.9974 48.76 0.0026 0.13 Site Preparation 3 8 18.5 444
LDA 0.50 29.94 0.9986 7.40

16.36 0.0014 0.01
LDT1 0.25 24.89 0.9998 4.46 0.0002 0.00 0.02 1.97 LDT2 0.25 24.59 0.9974 4.50 0.0026 0.01 Grading 6 10 18.5 1,110
LDA 0.50 29.94 0.9986 18.51

40.91 0.0014 0.03
LDT1 0.25 24.89 0.9998 11.15 0.0002 0.00 0.06 4.93 LDT2 0.25 24.59 0.9974 11.25 0.0026 0.03 Building
Construction 220 26 18.5 105,820
LDA 0.50 29.94 0.9986 1,764.46
3,900.15

0.0014 2.46
LDT1 0.25 24.89 0.9998 1,062.88 0.0002 0.19 5.51 470.45 LDT2 0.25 24.59 0.9974 1,072.81 0.0026 2.85 Paving 10 15 18.5 2,775
LDA 0.50 29.94 0.9986 46.27
102.28

0.0014 0.06
LDT1 0.25 24.89 0.9998 27.87 0.0002 0.01 0.14 12.34 LDT2 0.25 24.59 0.9974 28.13 0.0026 0.07 Architectural
Coating 10 5 18.5 925
LDA 0.50 29.94 0.9986 15.42

34.09 0.0014 0.02
LDT1 0.25 24.89 0.9998 9.29 0.0002 0.00 0.05 4.11 LDT2 0.25 24.59 0.9974 9.38 0.0026 0.02 Subtotal Worker Trips Energy Consumption Gasoline (Gal.) 4,271.07 Diesel (Gal.) 6.03 515.19 Vendor Trips
Building
Construction 220 4 10.2 8,976
MHDT 0.50 7.79 0.3129 180.24
180.57

0.6871 395.77
1,126.54 176.51 HHDT 0.50 6.14 0.0005 0.33 0.9995 730.76 Subtotal Vendor Trips Energy Consumption Gasoline (Gal.) 180.57 Diesel (Gal.) 1,126.54 176.51 Hauling Trips
Demolition 20 51 20.0 20,400 HHDT 1.00 6.14 0.0005 1.50 1.50 0.9995 3,321.65 3,321.65 456.51 Grading 6 729 20.0 87,480 HHDT 1.00 6.14 0.0005 6.44 6.44 0.9995 14,244.04 14,244.04 1,957.64 Subtotal Hauling Trips Energy Consumption Gasoline (Gal.) 7.94 Diesel (Gal.) 17,565.69 2,414.15 Total On-Road Construction Trips Energy Consumption Gasoline (Gal.) 4,459.57 Diesel (Gal.) 18,698.26 3,105.85 1 CalEEMod defaults. 2 HP-hrs. = Horsepower hours. 3 Source: Carl Moyer Program Guidelines. 2017 Revisions. Table D-21. https://www.arb.ca.gov/msprog/moyer/guidelines/current.htm.4 MMBTU = Millions of BTU, assuming 1 gallon of diesel fuel = 137,381 BTU.

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8.3.3.2 Petroleum Consumption – Operation
The project is expected to consume energy from auto and truck trips generated by the proposed land uses. Operational vehicle trips are associated with workers, customers, and vendors/non-workers (i.e., delivery, service, maintenance vehicles, etc.) traveling to and from the site. EMFAC2021 vehicle fuel consumption data is provided in Appendix B.

Table 8-5 shows the project’s petroleum energy consumption for all operational trips generated by the project on an annual basis.

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Table 8-5 | Operational Trips Energy Consumption - Annual Vehicle Class Vehicle Mix
Average Fuel
Economy
(MPG)
Annual VMT
Gasoline Diesel
MMBTU/yr.

Fuel Split
Fuel
Consumption
(Gal.)
Fuel Split
Fuel
Consumption
(Gal.)
LDA 50.42% 29.94
905,531

0.9986 15,226.61 0.0014 21.27 1,836.65
LDT1 4.13% 24.89 0.9998 1,501.66 0.0002 0.27 180.88 LDT2 23.72% 24.59 0.9974 8,709.95 0.0026 23.11 1,052.11 MDV 14.70% 20.00 0.9896 6,584.21 0.0104 69.46 802.47
LHD1 2.80% 15.84 0.7199 1,152.41 0.2801 448.44 200.39 LHD2 0.42% 15.05 0.4505 113.76 0.5495 138.73 32.76 MHD 0.90% 7.79 0.3129 328.91 0.6871 722.23 138.83
HHD 0.33% 6.14 0.0005 0.22 0.9995 488.32 67.11
OBUS 0.04% 6.01 0.5471 29.15 0.4529 24.13 6.83
UBUS 0.04% 7.01 0.9852 46.79 0.0148 0.70 5.73
MCY 2.23% 41.68 1.0000 485.18 0.0000 0.00 58.43
SBUS 0.06% 8.34 0.6144 37.78 0.3856 23.71 7.81
MH 0.22% 5.77 0.8268 280.21 0.1732 58.69 41.81
Total Operational Trips Energy Usage
Gasoline
Consumption
(Gal.)
34,496.84
Diesel
Consumption
(Gal.)
2,019.06 4,431.81

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8.4 Summary of Project Energy Consumption
Table 8-6 provides a summary of the project’s annual operational energy consumption.

Table 8-6 | Total Annual Energy Consumption
Activity Energy Consumption
(MMBTU/yr.)1
Operational Electricity 732.88
Operational Natural Gas --
Operational Petroleum 4,431.81
Total 5,164.69
1 MBTU/yr. = Million British Thermal Units per year.

8.5 Energy Impacts
This analysis has been prepared within the context of the CEQA Guidelines, Appendix F, Energy Conservation, and Appendix G, Environmental Checklist Form. According to CEQA, the goal of conserving energy implies the wise and efficient use of energy through decreasing overall per capita energy consumption, decreasing reliance on fossil fuels (such as coal, natural gas, and oil), and increasing reliance on renewable energy sources (CEQA Guidelines, Appendix F).

A significant environmental impact would result if the project would:
a. Result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation; or b. Conflict with or obstruct a state or local plan for renewable energy or energy efficiency.

8.5.1 Energy Impact – A
Would the project result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? The project will implement the mandatory requirements of California’s Building Efficiency Standards (Title 24, Part 6) to reduce operational energy consumption. California’s building standards are some of the strictest in the nation and the project’s compliance with the Building Code will ensure that wasteful, inefficient or unnecessary consumption of energy is minimized. The California Building Code is designed to reduce the amount of energy needed to heat or cool a building, reduce energy usage for lighting and appliances and promote usage of energy from renewable sources.

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In particular, the project is expected to comply with Section 110.10 of the building code regarding mandatory requirements for solar readiness and provide a rooftop solar zone.

Hence, the project would not result in wasteful, inefficient, or unnecessary consumption of energy resources, and the impact is considered less than significant.

8.5.2 Energy Impact – B
Would the project conflict with or obstruct a state or local plan for renewable energy or energy efficiency?
The project is not expected to conflict with or obstruct a state or local plan for renewable energy or energy efficiency.

The project will purchase electricity through Southern California Edison which is subject to the requirements of California Senate Bill 100 (SB 100). SB 100 is the most stringent and current energy legislation in California; requiring that renewable energy resources and zero-carbon resources supply 100% of retail sales of electricity to California end-use customers and 100% of electricity procured to serve all state agencies by December 31, 2045.3

In addition, the project will include onsite solar photovoltaic energy generation in compliance with the California Title 24 Building Energy Efficiency Standards. Title 24 requires new multifamily developments to incorporate solar PV systems sized to serve onsite electricity demand, thereby directly supporting state renewable energy and energy efficiency policies.

The project will also comply with the mandatory requirements of California’s Green Building and Building Energy Efficiency standards that promote renewable energy and energy efficiency.

Hence, the project would not conflict with or obstruct a state or local plan for renewable energy or energy efficiency, and the impact is considered less than significant. 3 SB-100 California Renewables Portfolio Standard Program. http://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201720180SB100

Appendices

Appendix A
CalEEMod Emissions Outputs

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Toll Brothers Laguna Hills Townhomes Custom Report
Table of Contents

1. Basic Project Information

1.1. Basic Project Information

1.2. Land Use Types

1.3. User-Selected Emission Reduction Measures by Emissions Sector

2. Emissions Summary

2.1. Construction Emissions Compared Against Thresholds

2.2. Construction Emissions by Year, Unmitigated

2.3. Construction Emissions by Year, Mitigated

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, Unmitigated

2.6. Operations Emissions by Sector, Mitigated

3. Construction Emissions Details

3.1. Demolition (2026) - Unmitigated

3.2. Demolition (2026) - Mitigated

3.3. Site Preparation (2026) - Unmitigated

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3.4. Site Preparation (2026) - Mitigated

3.5. Grading (2026) - Unmitigated

3.6. Grading (2026) - Mitigated

3.7. Building Construction (2026) - Unmitigated

3.8. Building Construction (2026) - Mitigated

3.9. Building Construction (2027) - Unmitigated

3.10. Building Construction (2027) - Mitigated

3.11. Paving (2027) - Unmitigated

3.12. Paving (2027) - Mitigated

3.13. Architectural Coating (2027) - Unmitigated

3.14. Architectural Coating (2027) - Mitigated

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated

4.1.2. Mitigated

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated

4.2.2. Electricity Emissions By Land Use - Mitigated

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4.2.3. Natural Gas Emissions By Land Use - Unmitigated

4.2.4. Natural Gas Emissions By Land Use - Mitigated

4.3. Area Emissions by Source

4.3.1. Unmitigated

4.3.2. Mitigated

4.4. Water Emissions by Land Use

4.4.1. Unmitigated

4.4.2. Mitigated

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated

4.5.2. Mitigated

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated

4.6.2. Mitigated

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated

4.7.2. Mitigated

4.8. Stationary Emissions By Equipment Type

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4.8.1. Unmitigated

4.8.2. Mitigated

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated

4.9.2. Mitigated

4.10. Soil Carbon Accumulation By Vegetation Type

4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated

4.10.4. Soil Carbon Accumulation By Vegetation Type - Mitigated

4.10.5. Above and Belowground Carbon Accumulation by Land Use Type - Mitigated

4.10.6. Avoided and Sequestered Emissions by Species - Mitigated

5. Activity Data

5.1. Construction Schedule

5.2. Off-Road Equipment

5.2.1. Unmitigated

5.2.2. Mitigated

5.3. Construction Vehicles

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5.3.1. Unmitigated

5.3.2. Mitigated

5.4. Vehicles

5.4.1. Construction Vehicle Control Strategies

5.5. Architectural Coatings

5.6. Dust Mitigation

5.6.1. Construction Earthmoving Activities

5.6.2. Construction Earthmoving Control Strategies

5.7. Construction Paving

5.8. Construction Electricity Consumption and Emissions Factors

5.9. Operational Mobile Sources

5.9.1. Unmitigated

5.9.2. Mitigated

5.10. Operational Area Sources

5.10.1. Hearths

5.10.2. Architectural Coatings

5.10.3. Landscape Equipment

5.10.4. Landscape Equipment - Mitigated

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5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.11.2. Mitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.12.2. Mitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated

5.13.2. Mitigated

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated

5.14.2. Mitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.15.2. Mitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

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5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated

5.18.1.2. Mitigated

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.1.2. Mitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

5.18.2.2. Mitigated

8. User Changes to Default Data

8.1. Justifications

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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name Toll Brothers Laguna Hills Townhomes
Construction Start Date 2/1/2026
Operational Year 2026
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 6.0
Location 23161 Mill Creek Dr, Laguna Hills, CA 92653, USA County Orange
City Laguna Hills
Air District South Coast AQMD
Air Basin South Coast
TAZ 5929
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.35

1.2. Land Use Types
Land Use Subtype Size Unit Lot Acreage Building Area (sq ft) Landscape Area (sq ft)
Special Landscape
Area (sq ft)
Population Description
Condo/Townhouse 36 Dwelling Unit 1.5 72,432 30,000 0.00 107 —

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Parking Lot 0.92 Acre 0.92 0.00 0.00 0.00 — —

1.3. User-Selected Emission Reduction Measures by Emissions Sector Sector # Measure Title
Energy E-15 Require All-Electric Development

2. Emissions Summary

2.1. Construction Emissions Compared Against Thresholds Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Un/Mit. TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.34 0.33 3.9 14 0.02 0.04 0.37 0.41 0.04 0.09 0.13 — 2,659 2,659 0.10 0.05 1.5 2,677 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 47 47 63 41 0.36 0.69 16 17 0.69 5.1 5.8 — 52,564 52,564 3.9 7.9 2.6 55,028 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 1.3 1.3 3.7 9.7 0.02 0.04 0.70 0.74 0.04 0.17 0.21 — 2,731 2,731 0.14 0.19 1.3 2,792 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.24 0.24 0.67 1.8 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 — 452 452 0.02 0.03 0.21 462

2.2. Construction Emissions by Year, Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Year TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e

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Daily -
Summer
(Max)
— — — — — — — — — — — — — — — — — —
2026 0.34 0.33 3.9 14 0.02 0.04 0.37 0.41 0.04 0.09 0.13 — 2,659 2,659 0.10 0.05 1.5 2,677 Daily -
Winter
(Max)
— — — — — — — — — — — — — — — — — —
2026 5.1 0.97 63 41 0.36 0.69 16 17 0.69 5.1 5.8 — 52,564 52,564 3.9 7.9 2.6 55,028 2027 47 47 3.9 14 0.02 0.04 0.37 0.41 0.04 0.09 0.13 — 2,635 2,635 0.10 0.05 0.03 2,652 Average
Daily
— — — — — — — — — — — — — — — — — —
2026 0.32 0.23 3.7 9.7 0.02 0.04 0.70 0.74 0.04 0.17 0.21 — 2,731 2,731 0.14 0.19 1.3 2,792 2027 1.3 1.3 0.22 0.78 < 0.005 < 0.005 0.02 0.02 < 0.005 < 0.005 0.01 — 138 138 0.01 < 0.005 0.03 138 Annual — — — — — — — — — — — — — — — — — —
2026 0.06 0.04 0.67 1.8 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 — 452 452 0.02 0.03 0.21 462 2027 0.24 0.24 0.04 0.14 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 23 23 < 0.005 < 0.005 < 0.005 23

2.3. Construction Emissions by Year, Mitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Year TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily -
Summer
(Max)
— — — — — — — — — — — — — — — — — —
2026 0.34 0.33 3.9 14 0.02 0.04 0.37 0.41 0.04 0.09 0.13 — 2,659 2,659 0.10 0.05 1.5 2,677 Daily -
Winter
(Max)
— — — — — — — — — — — — — — — — — —
2026 5.1 0.97 63 41 0.36 0.69 16 17 0.69 5.1 5.8 — 52,564 52,564 3.9 7.9 2.6 55,028 2027 47 47 3.9 14 0.02 0.04 0.37 0.41 0.04 0.09 0.13 — 2,635 2,635 0.10 0.05 0.03 2,652 Average
Daily
— — — — — — — — — — — — — — — — — —
2026 0.32 0.23 3.7 9.7 0.02 0.04 0.70 0.74 0.04 0.17 0.21 — 2,731 2,731 0.14 0.19 1.3 2,792

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2027 1.3 1.3 0.22 0.78 < 0.005 < 0.005 0.02 0.02 < 0.005 < 0.005 0.01 — 138 138 0.01 < 0.005 0.03 138 Annual — — — — — — — — — — — — — — — — — —
2026 0.06 0.04 0.67 1.8 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 — 452 452 0.02 0.03 0.21 462 2027 0.24 0.24 0.04 0.14 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 23 23 < 0.005 < 0.005 < 0.005 23

2.4. Operations Emissions Compared Against Thresholds
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Un/Mit. TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 3.0 2.8 0.89 11 0.02 0.03 2.1 2.1 0.03 0.52 0.55 17 2,954 2,971 1.8 0.08 8.1 3,050 Mit. 2.9 2.8 0.67 11 0.02 0.01 2.1 2.1 0.01 0.52 0.54 17 2,680 2,697 1.8 0.08 8.1 2,775 %
Reduced
1% < 0.5% 25% 1% 6% 57% — 1% 59% — 3% — 9% 9% 1% — — 9% Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 2.8 2.7 0.93 8.0 0.02 0.03 2.1 2.1 0.03 0.52 0.55 17 2,862 2,879 1.8 0.09 0.71 2,952 Mit. 2.7 2.6 0.71 7.9 0.02 0.01 2.1 2.1 0.01 0.52 0.54 17 2,587 2,604 1.8 0.09 0.71 2,677 %
Reduced
1% < 0.5% 24% 1% 6% 59% — 1% 61% — 3% — 10% 10% 1% — — 9% Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 2.7 2.6 0.84 8.3 0.02 0.03 1.7 1.8 0.03 0.44 0.47 17 2,376 2,392 1.8 0.07 3.3 2,464 Mit. 2.7 2.6 0.62 8.2 0.02 0.01 1.7 1.8 0.01 0.44 0.45 17 2,101 2,118 1.8 0.07 3.3 2,188 %
Reduced
1% < 0.5% 26% 1% 7% 62% — 1% 64% — 4% — 12% 11% 1% — — 11% Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.50 0.48 0.15 1.5 < 0.005 0.01 0.32 0.32 0.01 0.08 0.09 2.8 393 396 0.30 0.01 0.54 408

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Mit. 0.49 0.48 0.11 1.5 < 0.005 < 0.005 0.32 0.32 < 0.005 0.08 0.08 2.8 348 351 0.30 0.01 0.54 362 %
Reduced
1% < 0.5% 26% 1% 7% 62% — 1% 64% — 4% — 12% 11% 1% 1% — 11%

2.5. Operations Emissions by Sector, Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Sector TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 1.1 0.97 0.65 8.5 0.02 0.01 2.1 2.1 0.01 0.52 0.54 — 2,155 2,155 0.09 0.07 7.5 2,187 Area 1.9 1.9 0.02 2.0 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 213 213 0.01 < 0.005 — 214 Energy 0.03 0.01 0.22 0.09 < 0.005 0.02 — 0.02 0.02 — 0.02 — 569 569 0.04 < 0.005 — 571 Water — — — — — — — — — — — 2.6 17 20 0.27 0.01 — 28
Waste — — — — — — — — — — — 14 0.00 14 1.4 0.00 — 50
Refrig. — — — — — — — — — — — — — — — — 0.52 0.52
Total 3.0 2.8 0.89 11 0.02 0.03 2.1 2.1 0.03 0.52 0.55 17 2,954 2,971 1.8 0.08 8.1 3,050 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 1.1 0.96 0.71 7.9 0.02 0.01 2.1 2.1 0.01 0.52 0.54 — 2,068 2,068 0.10 0.08 0.20 2,094 Area 1.7 1.7 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 207 207 0.01 < 0.005 — 208 Energy 0.03 0.01 0.22 0.09 < 0.005 0.02 — 0.02 0.02 — 0.02 — 569 569 0.04 < 0.005 — 571 Water — — — — — — — — — — — 2.6 17 20 0.27 0.01 — 28
Waste — — — — — — — — — — — 14 0.00 14 1.4 0.00 — 50
Refrig. — — — — — — — — — — — — — — — — 0.52 0.52
Total 2.8 2.7 0.93 8.0 0.02 0.03 2.1 2.1 0.03 0.52 0.55 17 2,862 2,879 1.8 0.09 0.71 2,952 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 0.88 0.81 0.61 6.8 0.02 0.01 1.7 1.8 0.01 0.44 0.45 — 1,771 1,771 0.08 0.07 2.8 1,796

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Area 1.8 1.8 0.01 1.4 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 18 18 < 0.005 < 0.005 — 18 Energy 0.03 0.01 0.22 0.09 < 0.005 0.02 — 0.02 0.02 — 0.02 — 569 569 0.04 < 0.005 — 571 Water — — — — — — — — — — — 2.6 17 20 0.27 0.01 — 28
Waste — — — — — — — — — — — 14 0.00 14 1.4 0.00 — 50
Refrig. — — — — — — — — — — — — — — — — 0.52 0.52
Total 2.7 2.6 0.84 8.3 0.02 0.03 1.7 1.8 0.03 0.44 0.47 17 2,376 2,392 1.8 0.07 3.3 2,464 Annual — — — — — — — — — — — — — — — — — —
Mobile 0.16 0.15 0.11 1.2 < 0.005 < 0.005 0.32 0.32 < 0.005 0.08 0.08 — 293 293 0.01 0.01 0.46 297 Area 0.33 0.33 < 0.005 0.26 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 3.0 3.0 < 0.005 < 0.005 — 3.0 Energy < 0.005 < 0.005 0.04 0.02 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 94 94 0.01 < 0.005 — 95 Water — — — — — — — — — — — 0.43 2.8 3.3 0.04 < 0.005 — 4.7 Waste — — — — — — — — — — — 2.4 0.00 2.4 0.24 0.00 — 8.3 Refrig. — — — — — — — — — — — — — — — — 0.09 0.09
Total 0.50 0.48 0.15 1.5 < 0.005 0.01 0.32 0.32 0.01 0.08 0.09 2.8 393 396 0.30 0.01 0.54 408

2.6. Operations Emissions by Sector, Mitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Sector TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 1.1 0.97 0.65 8.5 0.02 0.01 2.1 2.1 0.01 0.52 0.54 — 2,155 2,155 0.09 0.07 7.5 2,187 Area 1.9 1.9 0.02 2.0 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 213 213 0.01 < 0.005 — 214 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 295 295 0.02 < 0.005 — 296 Water — — — — — — — — — — — 2.6 17 20 0.27 0.01 — 28
Waste — — — — — — — — — — — 14 0.00 14 1.4 0.00 — 50
Refrig. — — — — — — — — — — — — — — — — 0.52 0.52
Total 2.9 2.8 0.67 11 0.02 0.01 2.1 2.1 0.01 0.52 0.54 17 2,680 2,697 1.8 0.08 8.1 2,775

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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Mobile 1.1 0.96 0.71 7.9 0.02 0.01 2.1 2.1 0.01 0.52 0.54 — 2,068 2,068 0.10 0.08 0.20 2,094 Area 1.7 1.7 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 207 207 0.01 < 0.005 — 208 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 295 295 0.02 < 0.005 — 296 Water — — — — — — — — — — — 2.6 17 20 0.27 0.01 — 28
Waste — — — — — — — — — — — 14 0.00 14 1.4 0.00 — 50
Refrig. — — — — — — — — — — — — — — — — 0.52 0.52
Total 2.7 2.6 0.71 7.9 0.02 0.01 2.1 2.1 0.01 0.52 0.54 17 2,587 2,604 1.8 0.09 0.71 2,677 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 0.88 0.81 0.61 6.8 0.02 0.01 1.7 1.8 0.01 0.44 0.45 — 1,771 1,771 0.08 0.07 2.8 1,796 Area 1.8 1.8 0.01 1.4 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 18 18 < 0.005 < 0.005 — 18 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 295 295 0.02 < 0.005 — 296 Water — — — — — — — — — — — 2.6 17 20 0.27 0.01 — 28
Waste — — — — — — — — — — — 14 0.00 14 1.4 0.00 — 50
Refrig. — — — — — — — — — — — — — — — — 0.52 0.52
Total 2.7 2.6 0.62 8.2 0.02 0.01 1.7 1.8 0.01 0.44 0.45 17 2,101 2,118 1.8 0.07 3.3 2,188 Annual — — — — — — — — — — — — — — — — — —
Mobile 0.16 0.15 0.11 1.2 < 0.005 < 0.005 0.32 0.32 < 0.005 0.08 0.08 — 293 293 0.01 0.01 0.46 297 Area 0.33 0.33 < 0.005 0.26 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 3.0 3.0 < 0.005 < 0.005 — 3.0 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 49 49 < 0.005 < 0.005 — 49 Water — — — — — — — — — — — 0.43 2.8 3.3 0.04 < 0.005 — 4.7 Waste — — — — — — — — — — — 2.4 0.00 2.4 0.24 0.00 — 8.3 Refrig. — — — — — — — — — — — — — — — — 0.09 0.09
Total 0.49 0.48 0.11 1.5 < 0.005 < 0.005 0.32 0.32 < 0.005 0.08 0.08 2.8 348 351 0.30 0.01 0.54 362

3. Construction Emissions Details

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3.1. Demolition (2026) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.42 0.39 2.6 15 0.02 0.08 — 0.08 0.08 — 0.08 — 2,494 2,494 0.10 0.02 — 2,503 Demoliti
on
— — — — — — 2.8 2.8 — 0.43 0.43 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.02 0.02 0.14 0.80 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 137 137 0.01 < 0.005 — 137 Demoliti
on
— — — — — — 0.15 0.15 — 0.02 0.02 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent
< 0.005 < 0.005 0.03 0.15 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 23 23 < 0.005 < 0.005 — 23 Demoliti
on
— — — — — — 0.03 0.03 — < 0.005 < 0.005 — — — — — — —

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Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.04 0.04 0.04 0.57 0.00 0.00 0.16 0.16 0.00 0.04 0.04 — 155 155 < 0.005 0.01 0.01 157 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.34 0.05 4.3 1.9 0.02 0.04 0.92 0.97 0.04 0.26 0.30 — 3,489 3,489 0.26 0.55 0.18 3,661 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.03 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 8.6 8.6 < 0.005 < 0.005 0.01 8.7 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.02 < 0.005 0.24 0.10 < 0.005 < 0.005 0.05 0.05 < 0.005 0.01 0.02 — 191 191 0.01 0.03 0.17 201 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.4 1.4 < 0.005 < 0.005 < 0.005 1.4 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling < 0.005 < 0.005 0.04 0.02 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 — 32 32 < 0.005 0.01 0.03 33

3.2. Demolition (2026) - Mitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —

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Off-Roa
Equipment

0.42 0.39 2.6 15 0.02 0.08 — 0.08 0.08 — 0.08 — 2,494 2,494 0.10 0.02 — 2,503 Demoliti
on
— — — — — — 2.8 2.8 — 0.43 0.43 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.02 0.02 0.14 0.80 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 137 137 0.01 < 0.005 — 137 Demoliti
on
— — — — — — 0.15 0.15 — 0.02 0.02 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent
< 0.005 < 0.005 0.03 0.15 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 23 23 < 0.005 < 0.005 — 23 Demoliti
on
— — — — — — 0.03 0.03 — < 0.005 < 0.005 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
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Daily,
Winter
(Max)
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Worker 0.04 0.04 0.04 0.57 0.00 0.00 0.16 0.16 0.00 0.04 0.04 — 155 155 < 0.005 0.01 0.01 157 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.34 0.05 4.3 1.9 0.02 0.04 0.92 0.97 0.04 0.26 0.30 — 3,489 3,489 0.26 0.55 0.18 3,661