Lake Forest City Council
March 17, 2026

4.3 Operational Emissions 27

4.3.1 Area Sources 27

4.3.2 Energy Sources 27

4.3.3 Stationary Sources 28
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Contents Ramboll
CONTENTS (Continued)
Page

4.3.4 Mobile Sources 28

4.3.5 Total Operational Emissions 30

5. CO HOTSPOTS 31

6. PROJECT INVENTORY IN CONTEXT 34

6.1 Threshold 1: Would the Project conflict with or obstruct implementation of the applicable air quality plan? 34

6.2 Threshold 2: Would the Project result in a cumulatively considerable net increase of any criteria pollutant for which the Project region is non-attainment under an applicable federal or state ambient air quality standard? 37

6.3 Threshold 3: Would the Project expose sensitive receptors to substantial pollutant concentrations? 37

6.3.1 Localized Significance Thresholds 37

6.3.2 Localized Carbon Monoxide Impacts 37

6.4 Threshold 4 38
TABLES
Table 2-1: Summary of National and California Ambient Air Quality Standards Table 2-2: National and California Ambient Air Quality Standard Attainment Status Table 2-3: Air Quality Data for Nearest Monitoring Station Table 2-4: Frequency of Local Air Quality Standard Violations Table 3-1: South Coast Air Quality Management District Air Quality Significance Thresholds Table 4-1: Construction Schedule – Proposed Project
Table 4-2: Construction Equipment Assumptions
Table 4-3: Construction Material Movement
Table 4-4: Construction Demolition Assumptions
Table 4-5: Construction Trip Assumptions
Table 4-6: Operational Mobile Sources Activity Data
Table 4-7: Operational On-Site Mobile Sources Activity Data Table 4-8: Operational Emergency Generator Assumptions
Table 4-9: Summary of Maximum Daily Criteria Air Pollutant Emissions for Project Construction Table 4-10: Summary of Maximum Daily Criteria Air Pollutant Emission Estimates for Project Operation
Table 6-1: Comparison of On-site Project Emissions to SCAQMD Localized Significance Thresholds

APPENDICES
Appendix A: CalEEMod Runs
Appendix B: Emission Calculations for Project Construction Appendix C: Emission Calculations for Project Operation Item: 11
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Acronyms and Abbreviations Ramboll

ACRONYMS AND ABBREVIATIONS
Acronym Definition
AB Assembly Bill
ACC Advanced Clean Cars
ACF Advanced Clean Fleets
ACT Advanced Clean Trucks
AP-42 United States Environmental Protection Agency’s Compilation of Air Pollutant Emission Factors
APCD air pollution control district
AQ Air Quality
AQMD air quality management district
AQMP Air Quality Management Plan
ATCM Airborne Toxic Control Measure
CAA Clean Air Act
CAAQS California Ambient Air Quality Standards
CAFE Corporate Average Fuel Economy
CalEEMod California Emission Estimator Model
CAP criteria air pollutant
CAPCOA California Air Pollution Control Officers Association CARB California Air Resources Board
CCR California Code of Regulations
CEQA California Environmental Quality Act
CO carbon monoxide
CO2 carbon dioxide
CO2e carbon dioxide equivalent
DCFC direct current fast charging
DPM diesel particulate matter
EMFAC EMission FACtors model
EPA Environmental Protection Agency
GHG greenhouse gas
HD I/M heavy-duty vehicle inspection and maintenance
hp horsepower
HVAC heating, ventilation, and air conditioning
Kittelson Kittelson & Associates, Inc
LED light emitting diode
LST localized significance threshold
NAAQS National Ambient Air Quality Standards
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Acronym Definition
NHTSA National Highway Traffic Safety Administration
NO nitric oxide
NO2 nitrogen dioxide
NOX oxides of nitrogen
O3 ozone
OFFROAD Off-road Emissions Inventory Program model
Pb lead
PM particulate matter
PM10 particulate matter less than 10 microns in diameter PM2.5 particulate matter less than 2.5 microns in diameter ppm parts per million
Ramboll Ramboll Americas Engineering Solutions, Inc.

RTP Regional Transportation Plan
SAFE Safer Affordable Fuel-Efficient
SCAB South Coast Air Basin
SCAG Southern California Association of Governments
SCAQMD South Coast Air Quality Management District
SCS Sustainable Communities Strategy
SIP State Implementation Plan
SO2 sulfur dioxide
SOX sulfur oxide
TAC Toxic air contaminant
TRU transport refrigeration unit
USEPA United States Environmental Protection Agency
VMT Vehicle miles traveled
VOC volatile organic compound
ZEV zero-emission vehicle
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1. INTRODUCTION
Ramboll Americas Engineering Solutions, Inc. (Ramboll) was retained to prepare an Air Quality (AQ) Technical Report for the proposed Foothill Ranch Costco Project (Project) located at 26602 Towne Centre Drive, Foothill Ranch, California. The Project is located along State Route 241 between Bake Parkway and Alton Parkway within the Foothill Ranch Specific Planned Community at APN 612-093-13. This AQ Technical Report analyzes the proposed Project’s impacts on air quality from construction and operations. In particular, this report describes the existing setting of the Project site, describes the relevant regulatory setting, discusses the methodology used to evaluate AQ emissions related to the Project, and evaluates potential impacts related to AQ that would be affected as a result of implementation of the Project.

1.1 Existing Conditions
The site is currently designated as the Foothill Ranch Towne Centre Shopping Mall. Existing conditions of the site consist of one building surrounded by an asphalt pavement parking lot and landscape islands, the existing building served as a Regal Cinemas theater.

1.2 Proposed Project
Project scope includes demolition of approximately 16.3 acres of the existing asphalt pavement and landscaping, and removal of one (1) building located within Foothill Ranch Towne Centre. Proposed improvements include construction of a new ground up Costco Wholesale Membership Warehouse Building. The 35-foot-tall building will have a footprint of approximately 165,068 square feet with architectural enhancements. The parking lot will consist of surface parking and landscape planters. The current site plan proposes 913 stalls.

Existing underground utilities will also be removed to install new underground utilities to meet the Project site demands as it relates to stormwater, domestic water, fire water, sanitary sewer, and dry utilities. Truck ingress access will be provided from Towne Centre Drive, follow the north drive aisle along the property boundary, travel south along the west side of the building to the loading dock. Truck egress will follow the site’s proposed outer drive aisle, not interfering with the building’s main entrance.

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2. ENVIRONMENTAL AND REGULATORY BACKGROUND

2.1 Criteria Air Pollutants
Criteria air pollutants (CAPs) are defined as pollutants for which the federal and State governments have established ambient air quality standards, or criteria, for outdoor concentrations to protect public health. The federal and State standards have been set, with an adequate margin of safety, at levels above which concentrations could be harmful to human health and welfare. These standards are designed to protect the most sensitive people from illness or discomfort. Pollutants of concern include ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), particulate matter less than 10 microns in diameter (PM10), particulate matter less than 2.5 microns in diameter (PM2.5), and lead. In California, sulfates, vinyl chloride, hydrogen sulfide, and visibility-reducing particles are also regulated as CAPs. These pollutants are discussed in the following paragraphs.

2.1.1 Ozone
O3 is a colorless gas that is formed in the atmosphere when volatile organic compounds (VOCs), sometimes referred to as reactive organic gases, and oxides of nitrogen (NOX) react in the presence of ultraviolet sunlight. O3 is not a primary pollutant; it is a secondary pollutant formed by complex interactions of two pollutants directly emitted into the atmosphere. The primary sources of VOCs and NOX, the precursors of O3, are automobile exhaust and industrial sources. Meteorology and terrain play major roles in O3 formation, and ideal conditions occur during summer and early autumn on days with low wind speeds or stagnant air, warm temperatures, and cloudless skies. 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.

2.1.2 Nitrogen Dioxide
Most NO2, like O3, is not directly emitted into the atmosphere but is formed by an atmospheric chemical reaction between nitric oxide (NO) and atmospheric oxygen. NO and NO2 are collectively referred to as NOX and are major contributors to O3 formation. The primary sources of NO, the precursor to NO2, include automobile exhaust and industrial sources. High concentrations of NO2 can cause breathing difficulties and result in a brownish red cast to the atmosphere, causing reduced visibility. There is some indication of a relationship between NO2 and chronic pulmonary fibrosis, and some increase in bronchitis in children (2 and 3 years old) has also been observed at concentrations below 0.3 parts per million by volume.

2.1.3 Carbon Monoxide
CO is a colorless and odorless gas formed by the incomplete combustion of fossil fuels. CO is emitted almost exclusively from motor vehicles, power plants, refineries, industrial boilers, ships, aircraft, and trains. In areas, such as the Project location, automobile exhaust accounts for the majority of CO emissions. CO is a non-reactive air pollutant that dissipates relatively quickly; therefore, ambient CO concentrations generally follow the spatial and temporal distributions of vehicular traffic. CO concentrations are influenced by local meteorological conditions, primarily wind speed, topography, and atmospheric stability.

CO from motor vehicle exhaust can become locally concentrated when surface-based temperature inversions are combined with calm atmospheric conditions, a typical situation at dusk between November and February. The highest levels of CO typically occur during the Item: 11
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colder months of the year when inversion conditions, where a layer of warm air sits atop cool air, are more frequent and can trap pollutants close to the ground. In terms of health, CO competes with oxygen, often replacing it in the blood, thus reducing the blood’s ability to transport oxygen to vital organs. The results of excess CO exposure can be dizziness, fatigue, and impairment of central nervous system functions.

2.1.4 Sulfur Dioxide
SO2 is a colorless, pungent gas formed primarily by the combustion of sulfur-containing fossil fuels. The main sources of SO2 are coal and oil used in power plants and industries; as such, the highest levels of SO2 are generally found near large industrial complexes. In recent years, SO2 concentrations have been reduced by the increasingly stringent controls placed on stationary source emissions of SO2 and limits placed on the sulfur content of fuels. SO2 is an irritant gas that attacks the throat and lungs and can cause acute respiratory symptoms and diminished ventilator function in children. SO2 can also yellow plant leaves and erode iron and steel.

2.1.5 Particulate Matter
Particulate matter (PM) pollution consists of very small liquid and solid particles floating in the air, which can include smoke, soot, dust, salts, acids, and metals. PM can form when gases emitted from industries and motor vehicles undergo chemical reactions in the atmosphere. PM2.5 and PM10 represent fractions of particulate matter. Fine particulate matter, or PM2.5, is roughly 1/28 the diameter of a human hair. PM2.5 results from fuel combustion (e.g., motor vehicles, power generation, and industrial facilities), residential fireplaces, and woodstoves. In addition, PM2.5 can be formed in the atmosphere from gases such as sulfur oxides (SOX), NOX, and VOCs. Inhalable or coarse particulate matter, or PM10, is about one- seventh the thickness of a human hair. Major sources of PM10 include crushing or grinding operations; dust stirred up by vehicles traveling on roads; wood-burning stoves and fireplaces; dust from construction, landfills, and agriculture; wildfires and brush/waste burning; industrial sources; windblown dust from open lands; and atmospheric chemical and photochemical reactions.

PM2.5 and PM10 pose a greater health risk than larger-size particles. When inhaled, these tiny particles can penetrate the human respiratory system’s natural defenses and damage the respiratory tract. PM2.5 and PM10 can increase the number and severity of asthma attacks, cause or aggravate bronchitis and other lung diseases, and reduce the body’s ability to fight infections. Very small particles of substances such as lead, sulfates, and nitrates can cause lung damage directly or be absorbed into the bloodstream, causing damage elsewhere in the body. Additionally, these substances can transport absorbed gases, such as chlorides or ammonium, into the lungs, also causing injury. Whereas PM10 tends to collect in the upper portion of the respiratory system, PM2.5 is so tiny that it can penetrate deeper into the lungs and damage lung tissues. Suspended particulates also damage and discolor surfaces on which they settle, as well as produce haze and reduce regional visibility.

2.1.6 Lead
Lead (Pb) in the atmosphere occurs as PM. Sources of lead include leaded gasoline, the manufacturing of batteries, paint, ink, ceramics, ammunition, and secondary lead smelters.

Prior to 1978, mobile emissions were the primary source of atmospheric lead. Between 1978 and 1987, the phase-out of leaded gasoline reduced the overall inventory of airborne lead by nearly 95%. With the phase-out of leaded gasoline, secondary lead smelters, battery Item: 11
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recycling, and manufacturing facilities are becoming lead emission sources of greater concern.

Prolonged exposure to atmospheric lead poses a serious threat to human health. Health effects associated with exposure to lead include gastrointestinal disturbances, anemia, kidney disease, and in severe cases, neuromuscular and neurological dysfunction. Of particular concern are low-level lead exposures during infancy and childhood. Such exposures are associated with decrements in neurobehavioral performance, including intelligence quotient performance, psychomotor performance, reaction time, and growth.

2.1.7 Sulfates
Sulfates are the fully oxidized form of sulfur, which typically occur in combination with metals or hydrogen ions. Sulfates are produced from reactions of SO2 in the atmosphere.

Sulfates can result in respiratory impairment, as well as reduced visibility.

2.1.8 Vinyl Chloride
Vinyl chloride is a colorless gas with a mild, sweet odor, which has been detected near landfills, sewage plants, and hazardous waste sites, due to the microbial breakdown of chlorinated solvents. Short-term exposure to high levels of vinyl chloride in air can cause nervous system effects, such as dizziness, drowsiness, and headaches. Long-term exposure through inhalation can cause liver damage, including liver cancer.

2.1.9 Hydrogen Sulfide
Hydrogen sulfide is a colorless and flammable gas that has a characteristic odor of rotten eggs. Sources of hydrogen sulfide include geothermal power plants, petroleum refineries, sewers, and sewage treatment plants. Exposure to hydrogen sulfide can result in nuisance odors, as well as headaches and breathing difficulties at higher concentrations.

2.1.10 Visibility-Reducing Particles
Visibility-reducing particles are any particles in the air that obstruct the range of visibility.

Effects of reduced visibility can include obscuring the view shed of natural scenery, reduced airport safety, and discouraging tourism. Sources of visibility-reducing particles are the same as for PM2.5 described above.

2.2 Non-Criteria Air Pollutants

2.2.1 Toxic Air Contaminants
A substance is considered toxic if it has the potential to cause adverse health effects in humans, including increasing the risk of cancer upon exposure, or acute and/or chronic non-cancer health effects. A toxic substance released into the air is considered a toxic air contaminant (TAC). Examples include certain aromatic and chlorinated hydrocarbons, certain metals, and asbestos. TACs are generated by a number of sources, including stationary sources such as dry cleaners, gas stations, combustion sources, waste processing facilities and laboratories; mobile sources such as automobiles; and area sources such as landfills.

Adverse health effects associated with exposure to TACs may include carcinogenic (i.e., cancer-causing) and non-carcinogenic effects. Non-carcinogenic effects typically affect one or more target organ systems and may be experienced either on short-term (acute) or long-term (chronic) exposure to a given TAC.

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2.2.2 Diesel Particulate Matter
Diesel particulate matter (DPM) is part of a complex mixture that makes up diesel exhaust.

Diesel exhaust is composed of two phases, gas and particle, both of which contribute to health risks. The California Air Resources Board (CARB) classified “particulate emissions from diesel-fueled engines” (DPM; 17 California Code of Regulations [CCR] 93000) as a TAC in August 1998. DPM is emitted from a broad range of diesel engines: on-road diesel engines of trucks, buses, and cars, and off-road diesel engines including locomotives, marine vessels, and heavy-duty construction equipment, among others. Approximately 70% of all airborne cancer risk in California is associated with DPM.1 To reduce the cancer risk associated with DPM, CARB adopted a Diesel Risk Reduction Plan in 2000.

2.3 Regulatory Setting

2.3.1 Federal and State Ambient Air Quality Standards for Criteria Air Pollutants The Federal Clean Air Act (CAA) requires the adoption of National Ambient Air Quality Standards (NAAQS), which are periodically updated, to protect the public health and welfare from the effects of air pollution. Current federal standards are set for SO2, CO, NO2, O3, PM10, PM2.5, and Pb.2
The State of California also has established additional standards, known as the California Ambient Air Quality Standards (CAAQS), which are generally more restrictive than the NAAQS. The current NAAQS and CAAQS are shown in Table 2-1.

Specific geographic areas are classified as either "attainment" or "non-attainment" areas for each pollutant based upon the comparison of measured data with the NAAQS and CAAQS.

Those areas designated as “non-attainment” for purposes of NAAQS compliance are required to prepare regional air quality plans, which set forth a strategy for bringing an area into compliance with the standards. These regional air quality plans developed to meet federal requirements are included in an overall program referred to as the State Implementation Plan (SIP). If the SIP is deemed acceptable, the United States Environmental Protection Agency (USEPA) will delegate responsibility for implementation pursuant to the SIP to the State and/or its air districts therein.

Whenever the USEPA revises or establishes a new NAAQS, the State and the USEPA have specific obligations to ensure that the NAAQS is met.3 These are listed below:
• The USEPA must designate areas as meeting (attainment areas) or not meeting (non-attainment areas) the NAAQS within two years after its promulgation. • States must submit “infrastructure SIPs” to show that they have the basic air quality management program components in place to implement the NAAQS within three years after its promulgation.
• States must submit non-attainment area SIPs that outline the strategies and emission control measures that will improve air quality and make the area meet the NAAQS within 18 to 36 months after designation.
1 CARB. 2012. Summary: Diesel Particulate Matter Health Impacts. Available at:
https://ww2.arb.ca.gov/resources/summary-diesel-particulate-matter-health-impacts. Accessed: October 2025. 2 NAAQS. Available at: https://www.epa.gov/criteria-air-pollutants/naaqs-table. Accessed: October 2025. 3 USEPA. NAAQS Implementation Process. Available at:
https://www.epa.gov/criteria-air-pollutants/naaqs-implementation-process. Accessed: October 2025.

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The steps involved in the SIP process are described below.4 • SIPs must be developed with public input and be formally adopted by the State and submitted to the USEPA by the Governor’s designee (CARB in California). • The USEPA reviews each SIP and proposes to approve or disapprove all or part it. The public is then provided with an opportunity to comment on the USEPA's proposed action.

The USEPA considers public input before taking final action on a State's plan. • If the USEPA approves all or part of a SIP, those control measures are enforceable in federal court. In the event a State fails to submit an approvable SIP or if the USEPA disapproves a SIP, the USEPA is required to develop a Federal Implementation Plan.

Table 2-2 summarizes the attainment status for Orange County for the pollutants regulated by the NAAQS and CAAQS.5,6 As seen in Table 2-2, Orange County is currently in attainment (including where unclassified) for the federal PM10 standard, the federal and State CO standards, the federal and State NO2 standards, the federal and State lead standard, the federal and State SO2 standards, and the State standards for hydrogen sulfide, vinyl chloride, and sulfates. However, as also shown in Table 2-2, Orange County is currently designated as non-attainment for the State 1-hour O3 standard, the federal and State 8-hour O3 standards, the State PM10 standards, and the federal and State PM2.5 standards.

2.3.2 Federal Regulations and Policies

2.3.2.1 Federal Heavy-duty Engines and Vehicles Fuel Efficiency Standards In April 2007, the U.S. Supreme Court issued the Massachusetts v. Environmental Protection Agency (EPA) decision, which directed the Administrator of USEPA to determine whether greenhouse gas (GHG) emissions from new motor vehicles cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare, or whether the science is too uncertain to make a reasoned decision.7In response to this decision, President Bush directed the USEPA, the Department of Transportation, and the Department of Energy to establish regulations that reduce GHG emissions from motor vehicles, non-road vehicles, and non-road engines by 2008.8In 2009, the National Highway Traffic Safety Administration (NHTSA) issued a final rule regulating fuel efficiency for and GHG emissions from cars and light-duty trucks for model year 2011; and, in 2010, the USEPA and NHTSA issued a final rule regulating cars and light-duty trucks for model years 2012-2016.
4 USEPA. State Implementation Plan Development Process. Available at:
https://www.epa.gov/criteria-air-pollutants/naaqs-implementation-process. Accessed: October 2025. 5 USEPA. Non-attainment Areas for Criteria Pollutants (Green Book). Available at:
https://www.epa.gov/green-book. Accessed: October 2025. 6 California standard attainment status based on CARB website. Available at:
https://ww2.arb.ca.gov/resources/documents/maps-state-and-federal-area-designations.

Accessed: October 2025.
7 Massachusetts v. Environmental Protection Agency. April 2007. Available at:
https://tile.loc.gov/storage-services/service/ll/usrep/usrep549/usrep549497/usrep549497.pdf.

Accessed: October 2025.
8 Executive Order 13432 – Cooperation Among Agencies in Protecting the Environment With Respect to Greenhouse Gas Emissions From Motor Vehicles, Nonroad Vehicles, and Nonroad Engines. May 2007.

Available at: https://www.govinfo.gov/content/pkg/WCPD-2007-05-21/pdf/WCPD-2007-05-21-Pg631.pdf.

Accessed: October 2025.

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In 2010, President Obama issued a memorandum directing federal agencies to establish additional standards regarding fuel efficiency and GHG reduction, clean fuels, and advanced vehicle infrastructure. In response to this directive, the USEPA and NHTSA proposed stringent, coordinated federal GHG and fuel economy standards for model year 2017-2025 light-duty vehicles. The proposed standards are projected to achieve 163 grams/mile of carbon dioxide (CO2) in model year 2025, on an average industry fleet-wide basis, which is equivalent to 54.5 miles per gallon if this level were achieved solely through fuel efficiency.

The final rule was adopted in 2012 for model years 2017–2021, and NHTSA intends to set standards for model years 2022–2025 in a future rulemaking. These fuel efficiency standards of light-duty vehicles are anticipated to reduce CAP emissions as well.

In August 2017, the USEPA asked for additional information and data relevant to assessing whether the GHG emissions standards for model years 2022-2025 remain appropriate. In early 2018, the USEPA Administrator announced that the midterm evaluation for the GHG emissions standards for cars and light-duty trucks for model years 2022-2025 was completed and stated his determination that the current standards should be revised in light of recent data. Subsequently, in April 2018, the USEPA and NHTSA proposed to amend certain existing Corporate Average Fuel Economy (CAFE) standards and tailpipe carbon dioxide emissions standards for passenger cars and light trucks and establish new standards, covering model years 2022-2025. Compared to maintaining the post-2020 standards now in place, the pending proposal would increase U.S. fuel consumption.9 California and other states have announced their intent to challenge federal actions that would delay or eliminate GHG reductions. In April 2020, NHTSA and EPA amended the CAFE and GHG emissions standards for passenger cars and light trucks and established new less stringent standards, covering model years 2021 through 2026.

In addition to the regulations applicable to cars and light-duty trucks described above, in 2011, the USEPA and NHTSA announced fuel economy and GHG standards for medium- and heavy-duty trucks for model years 2014-2018 (Advanced Fuel Economy and GHG Standard – Phase 1).10 The standards for CO2 emissions and fuel consumption are tailored to three main vehicle categories: combination tractors, heavy-duty pickup trucks and vans, and vocational vehicles.

On September 27, 2019, the USEPA and NHTSA published the Safer Affordable Fuel-Efficient (SAFE) Rule (Part One).11 The SAFE Rule (Part One) went into effect in November 2019, and revoked California’s authority to set its own GHGs standards and set zero-emission vehicle mandates in California. The SAFE Rule (Part One) freezes new zero-emission vehicles (ZEV) sales at model year 2020 levels for year 2021 and beyond, and will likely result in a lower number of future ZEVs and a corresponding greater number of future gasoline internal combustion engine vehicles. In response to the USEPA’s adoption of the SAFE Rule 9 NHTSA. 2018. Federal Register, Vol. 83, No. 72, Rules & Regulations, Mid-Term Evaluation of Greenhouse Gas Emissions Standards for Model Year 2022-2025 Light Duty Vehicles. April 13. Available at:
https://www.federalregister.gov/documents/2018/04/13/2018-07364/mid-term-evaluation-of-greenhouse-gasemissions-standards-for-model-year-2022-2025-light-duty. Accessed: October 2025. 10 USEPA, Office of Transportation and Air Quality. 2011. Available at:
https://www.gpo.gov/fdsys/pkg/FR-2011-09-15/pdf/2011-20740.pdf. Accessed: October 2025. 11 USEPA and NHTSA. 2019. Federal Register, Vol. 84, No. 188, The Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule Part One: One National Program. September 27. Available at:
https://www.govinfo.gov/content/pkg/FR-2019-09-27/pdf/2019-20672.pdf. Accessed: October 2025.

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(Part One), CARB issued guidance regarding the adjustment of vehicle emissions factors to account for the rule’s implications on CAP and greenhouse gas emissions.12,13 The SAFE Rule is subject to ongoing litigation and on February 8, 2021 the D.C. Circuit Court of Appeals granted the Biden Administration’s motion to stay litigation over Part 1 of the SAFE Rule.

On April 22 and April 28, 2021, respectively, NHTSA and USEPA formally announced their intent to reconsider the SAFE Rule (Part One).14,15 A virtual public hearing for EPA’s Notice of Reconsideration of SAFE I was held on June 2, 2021. The NHTSA finalized the CAFE Pre-emption rulemaking to withdraw its portions of the SAFE I Rule on December 21, 2021.16 On March 9, 2022, USEPA reinstated California’s authority under the CAA to implement its own GHG emission standards and ZEV sales mandate and entirely rescinded the SAFE Rule (Part One).

In December 2021, the USEPA finalized federal GHG emissions standards for passenger cars and light trucks for model years 2023 through 2026. These standards are the strongest vehicle emissions standards ever established for the light-duty vehicle sector and are based on sound science and grounded in a rigorous assessment of current and future technologies.

The updated standards will result in avoiding more than 3 billion tons of GHG emissions through 2050.17 They are also expected to result in reductions of CAP emissions. 12 CARB. 2019. EMFAC Off-Model Adjustment Factors to Account for the SAFE Vehicle Rule Part One. November 20.

Available at:
https://ww2.arb.ca.gov/sites/default/files/2023-02/emfac_off_model_adjustment_factors_final_draft.pdf.

Accessed: October 2025.
13 CARB. 2020. EMFAC Off-Model Adjustment Factors for Carbon Dioxide Emissions to Account for the SAFE Vehicles Rule Part One and the Final SAFE Rule. June 26. Available at:
https://ww2.arb.ca.gov/sites/default/files/2023-02/emfac_off_model_co2_adjustment_factors_06262020- final.pdf. Accessed: October 2025.
14 NHTSA. 2021. NHTSA Advances Biden-Harris Administration’s Climate & Jobs Goals. April 22. Available at:
https://www.nhtsa.gov/press-releases/nhtsa-advances-biden-harris-administrations-climate-jobs-goals.

Accessed: October 2025.
15 USEPA. 2021. Federal Register, Vol. 86, No. 80, California State Motor Vehicle Pollution Control Standards; Advanced Clean Car Program; Reconsideration of a previous Withdrawal of a Waiver of Preemption; Opportunity for Public Hearing and Public Comment. April 28. Available at: https://www.epa.gov/regulations-emissionsvehicles-and-engines/notice-reconsideration-previous-withdrawal-waiver. Accessed: October 2025. 16 NHTSA. Available at: https://www.nhtsa.gov/laws-regulations/corporate-average-fuel-economy.

Accessed: October 2025.
17 USEPA. 2021. Final Rule to Revise Existing National GHG Emissions Standards for Passenger Cars and Light Trucks Through Model Year 2026. Available at: https://www.epa.gov/regulations-emissions-vehicles-andengines/final-rule-revise-existing-national-ghg-emissions. Accessed: October 2025.

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In April 2023, the EPA proposed a new more ambitious proposed standards for national GHG emissions standards from light-duty and medium-duty vehicles starting with 2027 model year vehicles.18 On March 20, 2024, EPA finalized these standards, which will phase in over model years 2027 to 2032. These standards build upon existing rules, and leverage advances in clean car technology to realize benefits to Americans such as the improvement of public health through reduction of CAP and GHG emissions from vehicles.19 In August 2016, the USEPA and NHTSA announced the adoption of the Phase 2 program20 related to the fuel economy and GHG standards for medium- and heavy-duty trucks. The phase two program will apply to vehicles with model year 2018 through 2027 for certain trailers, and model years 2021 through 2027 for semi-trucks, large pickup trucks, vans and all types of sizes of buses and work trucks. The final standards are expected to lower carbon dioxide emissions by approximately 1.1 billion metric tons and reduce oil consumption by up to two billion barrels over the lifetime of the vehicles sold under the program.21,22 These programs that focus on improving the fuel efficiency standards of medium- and heavy-duty trucks are anticipated to reduce CAP emissions as well.

On August 5, 2021, EPA announced plans to reduce GHG emissions and other harmful air pollutants from heavy-duty trucks through a series of rulemakings over the next three years.

The first rulemaking of this Clean Trucks Plan was the Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards, signed on December 20, 2022, which focuses on reducing emissions that form smog and soot and will apply to heavy-duty engines and vehicles beginning in model year 2027. Two additional rulemakings, Phase 3 greenhouse gas rule for heavy-duty engines and the multi-pollutant emissions standards for light-duty and medium-duty vehicles were signed in March 2024, and marked the completion of the Clean Trucks Plan.23
On January 20, 2025, newly re-elected President Trump issued an Executive Order (14148) entitled Initial Rescissions of Harmful Executive Orders and Actions, which revokes a Biden-era Executive Order 14037 that directed the USEPA and the Secretary of Transportation to consider beginning work on rulemakings to establish vehicle emissions standards and fuel economy standards for vehicles with model years 2027 and later. 18 United States Environmental Protection Agency. 2023. Proposed Rule: Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium-Duty Vehicles. Available at:
https://www.epa.gov/regulations-emissions-vehicles-and-engines/proposed-rule-multi-pollutant-emissionsstandards-model. Accessed: October 2025. 19 United States Environmental Protection Agency. 2023. Final Rule: Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium-Duty Vehicles. Available at: https://www.epa.gov/regulationsemissions-vehicles-and-engines/final-rule-multi-pollutant-emissions-standards-model. Accessed: October 2025. 20 USEPA, Office of Transportation and Air Quality. 2016. Available at:
https://www.gpo.gov/fdsys/pkg/FR-2016-10-25/pdf/2016-21203.pdf. Accessed: October 2025. 21 USEPA and NHTSA. 2016. Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium and Heavy-Duty Engines and Vehicles – Phase 2. Available at:
https://www.gpo.gov/fdsys/pkg/FR-2016-10-25/pdf/2016-21203.pdf. Accessed: October 2025. 22 USEPA and NHTSA. 2016. Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium and Heavy-Duty Engines and Vehicles – Phase 2. Available at:
https://www.gpo.gov/fdsys/pkg/FR-2016-10-25/pdf/2016-21203.pdf. Accessed: October 2025. 23 USEPA. Regulations for Emissions from Vehicles and Engines. Available at: https://www.epa.gov/regulationsemissions-vehicles-and-engines/regulations-greenhouse-gas-emissions-commercial-trucks.

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Executive Order 14148 directed NHTSA to commence review and reconsideration of all existing fuel economy standards for vehicle model years 2022 and later.24

2.3.2.2 Federal Hazardous Air Pollutants Program
The 1977 CAA Amendments required the USEPA to identify National Emissions Standards for Hazardous Air Pollutants to protect the public health and welfare. Hazardous air pollutants include certain VOCs, pesticides, herbicides, and radionuclides that present a tangible hazard, based on scientific studies of exposure to humans and other mammals. Under the 1990 CAA Amendments, which expanded the control program for hazardous air pollutants, 189 substances and chemical families were identified as hazardous air pollutants.

2.3.3 State Regulations and Policies

2.3.3.1 California’s Air Toxics Program
The State Air Toxics Program was established in 1983 under Assembly Bill (AB) 1807 (Tanner). The California TAC list identifies more than 700 pollutants, of which carcinogenic and non-carcinogenic toxicity criteria have been established for a subset of these pollutants pursuant to the California Health and Safety Code. In accordance with AB 2728, the state list includes the (federal) hazardous air pollutants.

The Air Toxics “Hot Spots” Information and Assessment Act of 1987 (AB 2588) seeks to identify and evaluate risk from air toxics sources; however, AB 2588 does not reduce the quantity of air toxics emissions. Instead, under AB 2588, TAC emissions from individual facilities are quantified and prioritized. “High-priority” facilities are required to perform a health risk assessment, and if specific thresholds are exceeded, are required to communicate the results to the public in the form of notices and public meetings.

In 2000, CARB approved a comprehensive Diesel Risk Reduction Plan to reduce diesel emissions from both new and existing diesel-fueled vehicles and engines. The plan is anticipated to result in an 85% decrease in statewide diesel health risk in 2020 compared with the diesel risk in 2000. Additional regulations apply to new trucks and diesel fuel, including the On-Road Heavy-Duty Diesel Vehicle (In-Use) Regulation, the On-Road Heavy-Duty (New) Vehicle Program, the In-Use Off-Road Diesel Vehicle Regulation, and the New Off-Road Compression-Ignition (Diesel) Engines and Equipment program. All of these regulations and programs have timetables by which manufacturers must comply and existing operators must upgrade their diesel-powered equipment. There also are several Airborne Toxic Control Measures that reduce diesel emissions, including In-Use Off-Road Diesel-Fueled Fleets (13 CCR 2449 et seq.) and In-Use On-Road Diesel-Fueled Vehicles (13 CCR 2025). 24 United States Department of Transportation. 2025. Memorandum to Office of the Administrator of the National Highway Traffic Safety Administration (NHTSA), Office of the Assistant Secretary of Policy (OST-P) AND Office of the General Counsel (OGC), Subject: Fixing the CAFÉ Program. January 28. Available at:
https://www.transportation.gov/sites/dot.gov/files/2025- 01/Signed%20Secretarial%20Memo%20re%20Fixing%20the%20CAFE%20Program.pdf.

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2.3.3.2 California Health and Safety Code Section 41700 This section of the Health and Safety Code states that a person shall not discharge from any source whatsoever quantities of air contaminants or other material that cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or that endanger the comfort, repose, health, or safety of any of those persons or the public, or that cause, or have a natural tendency to cause, injury or damage to business or property. This section also applies to sources of objectionable odors.

2.3.3.3 California’s Pavley Standards
AB 1493 ("the Pavley Standard" or AB 1493) required CARB to adopt regulations by January 1, 2005, to reduce GHG emissions from non-commercial passenger vehicles and light-duty trucks of model year 2009 through 2016.

CARB’s approach to passenger vehicles (cars and light trucks), under AB 1493, combines the control of smog-causing pollutants and GHG emissions into a single coordinated package of standards. This new approach also includes efforts to support and accelerate the numbers of plug-in hybrids and ZEVs in California. These standards will apply to all passenger and light-duty trucks used by customers, employees of and deliveries to the Project. While AB 1493 focuses on the reduction of GHG emissions, it is anticipated that this regulation would also help reduce CAPs.

2.3.3.4 California’s Advanced Clean Cars
In January 2012, CARB approved the Advanced Clean Cars (ACC) program,25 a new emissions control program for model year 2017 through 2025. The program combines the control of smog, soot, and GHGs with requirements for greater numbers of ZEVs. By 2025, when the rules will be fully implemented, the new automobiles will emit 34 percent fewer global warming gases and 75 percent fewer smog-forming emissions. While ACC focuses on the reduction of GHG emissions, it is anticipated that this regulation would also help reduce CAP emissions.

CARB has developed the Advanced Clean Cars II (ACC II) regulation which “will seek to reduce criteria and greenhouse gas emissions from new light- and medium-duty vehicles beyond the 2025 model year, and increase the number of ZEVs for sale”.26 The regulations were presented to the Board in June 2022. At a second hearing in August 2022 the Board approved the item. ACC II was approved by the Office of Administrative Law on November 30, 2022. In October 2023, CARB launched a new effort to consider potential amendments to the ACC II regulations, including updates to the tailpipe GHG emission standards and limited revisions to the Low-emission Vehicle and ZEV regulations. On December 18, 2024, the U.S. EPA granted a waiver for California’s ACC II regulation.27 25 Advanced Clean Cars Program. Available at:
https://ww2.arb.ca.gov/index.php/our-work/programs/advanced-clean-cars-program. Accessed: October 2025. 26 Advanced Clean Cars II Program. Available at:
https://ww2.arb.ca.gov/advanced-clean-cars-ii-meetings-workshops. Accessed: October 2025. 27 U.S. EPA. 2024. EPA Grants Waiver for California’s Advanced Clean Cars II Regulations. December 18. Available at: https://www.epa.gov/newsreleases/epa-grants-waiver-californias-advanced-clean-cars-ii-regulations.

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In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waiver for ACC II regulation using the Congressional Review Act. In response to this action, CARB stated that they “will pursue every available remedy to challenge these actions”28 and Governor Newson announced that California would join a 11-state coalition to advance clean cars.
29 2.3.3.5 Truck and Bus Regulation
The Truck and Bus Regulation (13 CCR 2025) requires diesel trucks and buses to be upgraded to reduce emissions; newer heavier trucks and buses must meet PM filter requirements; lighter and older heavier trucks must be replaced; and, by January 1, 2023, nearly all trucks and buses needed to have 2010 model year engines or equivalent to reduce PM and NOX emissions.30
The regulation applies to nearly all privately- and federally-owned diesel-fueled trucks and buses, and to privately- and publicly-owned school buses with a gross vehicle weight rating greater than 14,000 pounds. The regulation provides a variety of flexibility options tailored to fleets operating low use vehicles, fleets operating in selected vocations like agricultural and construction, and small fleets of three or fewer trucks.

2.3.3.6 Heavy-Duty Vehicle Inspection and Maintenance Program Following Senate Bill 210, CARB developed the heavy-duty vehicle inspection and maintenance (HD I/M) program31 to regulate the maintenance and proper function of vehicle emission control systems, which was approved by the CARB Board on December 9, 2021.

The program is designed to reduce smog-forming and toxic air pollutant emissions as a result of malfunctioning aftertreatment systems. The following program strategies ensure heavy-duty vehicles are well-maintained, repaired rapidly, and are functioning properly:
• Roadside emissions monitoring to screen for high-emitting vehicles; • Improved emissions testing procedures using on-board diagnostics data; • Emissions checks and data reporting at required intervals; and • Compliance verification requirements for freight contractors, seaports, and railyards.

Once fully implemented, the regulation is expected to reduce statewide NOX emissions by over 81 tons per day and PM emissions by 0.7 tons per day in 2037. 28 CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U. S. Senate. May 22. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolphresponds-illegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025. 29 Governor Gavin Newson. Following illegal Senate vote, California and 10 other states launch Affordable Clean Cars Coalition. May 23. Available at: https://www.gov.ca.gov/2025/05/23/following-illegal-senate-votecalifornia-and-10-other-states-launch-affordable-clean-cars-coalition/. Accessed: October 2025. 30 13 CCR 2025: Regulation to Reduce Emissions of Diesel Particulate Matter, Oxides of Nitrogen, and Other Pollutants from In-Use Heavy-Duty Diesel-Fueled Vehicles. Available at:
https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2008/truckbus08/eofroatt1.pdf. Accessed: October 2025. 31 CARB. Clean Truck Check (HD I/M). Available at: https://ww2.arb.ca.gov/our-work/programs/CTC.

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2.3.3.7 Heavy-Duty Omnibus Regulation
The Heavy-Duty Engine and Vehicle Omnibus Regulation32 and associated amendments (Heavy-Duty Omnibus Regulation) were approved by the CARB Board on December 22, 2021. This regulation implements two measures previously included within CARB’s Revised Proposed 2016 State Strategy for the SIP: a “Low-NOX Engine Standard” and a “Lower In-use Emission Performance Level” which aim to address emissions from new engines during certification and ensure continued emission controls for in-use heavy-duty vehicles throughout useful life, respectively. These measures are implemented through the modification of several pre-existing on-road heavy-duty program elements including updates to engine standards, on-board diagnostic system requirements, testing requirements, warranty and useful life requirements, and reporting requirements. In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waiver for the Heavy-Duty Omnibus Regulation using the Congressional Review Act. In response to this action, CARB stated that they “will pursue every available remedy to challenge these actions”.33

2.3.3.8 California’s Advanced Clean Trucks
In June 2020, CARB approved the Advanced Clean Trucks (ACT) regulation, which has requirements for manufacturer ZEV sales and a one-time reporting requirement for large entities and fleets.34 The Advanced Clean Truck Regulation is part of a holistic approach to accelerate a large-scale transition of zero-emission medium-and heavy-duty vehicles from Class 2b to Class 8. Manufacturers who certify Class 2b-8 chassis or complete vehicles with combustion engines are required to sell zero-emission trucks as an increasing percentage of their annual California sales from 2024 to 2035. By 2035, zero-emission truck/chassis sales need to be 55% of Class 2b – 3 truck sales, 75% of Class 4 – 8 straight truck sales, and 40% of truck tractor sales. Large employers including retailers, manufacturers, brokers and others are required to report information about shipments and shuttle services. Fleet owners, with 50 or more trucks, are required to report about their existing fleet operations.

This information helps to identify future strategies to ensure that fleets purchase available zero-emission trucks and place them in service where suitable to meet their needs. CARB has held recent workshops to discuss proposed amendments to the ACT regulation that would fulfill commitments in the Clean Truck Partnership agreement for CARB to propose a credit pooling concept for credits and deficits generated in states that have adopted the ACT regulation under section 177 of the federal CAA.35
32 CARB. Updated Informative Digest. Proposed Hearing to consider the Proposed Heavy-Duty Engine and Vehicle Omnibus regulation and Associated Amendments. Available at:
https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2020/hdomnibuslownox/uid.pdf. Accessed: October 2025. 33 CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U. S. Senate. May 22. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolphresponds-illegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025. 34 CARB. 2020. Advanced Clean Trucks. Available at:
https://ww2.arb.ca.gov/our-work/programs/advanced-clean-trucks. Accessed: October 2025. 35 CARB. 2024. Advanced Clean Trucks Pooling Workshop. Available at:
https://ww2.arb.ca.gov/sites/default/files/2024-12/241209actpres_ADA.pdf. Accessed: October 2025.

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In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waiver for ACT regulation using the Congressional Review Act. In response to this action, CARB stated that they “will pursue every available remedy to challenge these actions”.36

2.3.3.9 California’s Advanced Clean Fleets
In October 2022, CARB approved the Advanced Clean Fleets (ACF) regulation, which has requirements for fleets to phase in the use of ZEVs from 2024 to 2042 and beyond. The fleets required to comply with the regulation include State and local government agency fleets, high priority and federal fleets, and drayage fleets. The regulation also includes a requirement for manufacturers to only sell zero-emission trucks starting in 2036. The ACF regulation is meant to complement the ACT regulation and will contribute to meeting the goals set out in Governor Newsom’s Executive Order N-79-20. On January 13th, 2025 California withdrew its request for a waiver and authorization for the ACF regulation.37 CARB is not enforcing the existing portions of the ACF regulation that require a federal waiver or authorization. This includes the high priority and drayage fleet portions of the ACF regulation. Note, the State and local government fleets portion of the ACF remains unaffected as it does not require a federal waiver or authorization. 38 2.3.3.10 California’s Diesel Emissions Control Measures CARB has adopted a number of Airborne Toxic Control Measures (ATCMs) to control diesel particulate emissions and emissions from in-use on- and off-road diesel-fueled vehicles. With the assistance of the Advisory Committee and its subcommittees, CARB developed and approved the Risk Reduction Plan to Reduce Particulate Matter Emissions from Diesel-Fueled Engines and Vehicle39 and the Risk Management Guidance for the Permitting of New Stationary Diesel-Fueled Engines.
40 Various control measures adopted by CARB to reduce
diesel emissions are summarized below.

ATCM: Diesel-Fueled Commercial Motor Vehicle Idling
This ATCM applies to diesel-fueled commercial motor vehicles with gross vehicular weight ratings of greater than 10,000 pounds that are or must be licensed for operation on highways. The measure limits idling of trucks to a maximum of 5 minutes, except when the 36 CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U. S. Senate. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolph-respondsillegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025. 37 CARB. 2025. Withdrawal of California’s Request for a Waiver, Pursuant to Clean Air Act Section 209(b), and Request for Authorization, Pursuant to Clean Air Act Section 209(e)(2), for the Advanced Clean Fleets (ACF) Regulation, Docket ID EPA-HQ-OAR-2023-0589. January 13. Available at:
https://www.epa.gov/system/files/documents/2025-01/ca-acf-carb-withdrawal-ltr-2025-1-13.pdf.

Accessed: October 2025.
38 CARB. 2025. Advanced Clean Fleets. Available at:
https://ww2.arb.ca.gov/our-work/programs/advanced-clean-fleets. Accessed: October 2025. 39 CARB. 2000. Risk Reduction Plan to Reduce Particulate Matter Emissions from Diesel-Fueled Engines and Vehicles. Available at: https://www.arb.ca.gov/diesel/documents/rrpfinal.pdf. Accessed: October 2025. 40 CARB. 2008. California’s Diesel Risk Reduction Plan: Risk Management Guidance for the Permitting of New Stationary Diesel-Fueled Engines. Available at: https://www.arb.ca.gov/diesel/documents/rmg.htm.

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vehicle is queuing.41 While this ATCM focuses on the reduction of diesel particulate emissions as a toxic, this regulation would also help reduce CAP emissions.

ATCM: Stationary Compression-Ignition Engines
This ATCM establishes emission standards and fuel use requirements for new and in-use stationary engines used in prime and emergency back-up applications (non-agricultural) and for new stationary engines used in agricultural applications.42 While this ATCM focuses on the reduction of diesel particulate emissions as a toxic, this regulation would also help reduce CAP emissions.

ATCM: Transport Refrigeration Unit
This ATCM applies to transport refrigeration units (TRUs), which are commonly found on various transported containers, including truck vans, semi-truck trailers, shipping containers and railcars. TRUs are temperature control systems powered by small (typically 9 to 36 horsepower [hp]) diesel internal combustion engines. Despite their small individual size, TRUs are often active in dense congregations around distribution centers, truck stops, and other facilities, resulting in a significantly greater combined loading. This ATCM focused on the reduction of diesel particulate emissions as a toxic in order to improve air quality around these centers. Additionally, transitioning diesel TRUs to zero-emissions technologies is a priority because of Executive Order N-79-20, which set a goal of 100 percent zero-emission off-road vehicles and equipment in California by 2035.

2.3.3.11 In-Use Off-Road Diesel-Fueled Fleets
These regulations reduce diesel PM and NOX emissions from in-use, off-road heavy-duty diesel vehicles in California. Such vehicles typically are used in construction, mining, and industrial operations. The regulations, among other requirements, impose limits on idling; require all vehicles to be reported to CARB (using the Diesel Off-Road Online Reporting System) and labeled; restrict the adding of older vehicles into fleets; and, require fleets to reduce their emissions by retiring, replacing, or repowering older engines, or installing Verified Diesel Emission Control Strategies (i.e., exhaust retrofits).

The requirements and compliance dates of the regulations vary by fleet size. Large fleets have compliance deadlines each year from 2014 through 2023, medium fleets each year from 2017 through 2023, and small fleets each year from 2019 through 2028. 43 CARB
approved an amendment to the regulation aimed at further reducing emissions from the off-road sector on November 17, 2022. The target of the amendment aligns with the targets set out by the 2020 Mobile Source Strategy, which sets a goal of reducing statewide NOX emissions from the construction and earth-moving sector by 7.5 tons/day by 2031.44 41 13 CCR 2485: Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling.

Available at: https://ww2.arb.ca.gov/sites/default/files/classic/msprog/truck-idling/13ccr2485_09022016.pdf.

Accessed: October 2025.
42 17 CCR 93115: Airborne Toxic Control Measure for Stationary Compression Ignition (CI) Engines. Available at:
https://www.law.cornell.edu/regulations/california/17-CCR-93115. Accessed: October 2025. 43 13 CCR 2449: General Requirements for In-Use Off-Road Diesel-Fueled Fleets. Available at:
https://www.law.cornell.edu/regulations/california/13-CCR-2449. Accessed: October 2025. 44 CARB. Proposed Amendments to the In-Use Off-Road Diesel-Fueled Fleets Regulation. Available at:
https://ww2.arb.ca.gov/rulemaking/2022/off-roaddiesel. Accessed: October 2025.

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2.3.4 Local Regulations and Guidance
Air pollution often does not conform to City and/or county jurisdictional boundaries, and the State has been divided into air basins based on geographical and meteorological conditions.

Air pollution within each air basin is regulated by the regional air pollution control districts (APCDs)/air quality management districts (AQMDs), in a manner that is consistent with and in furtherance of standards adopted by the USEPA and CARB. The proposed Project site is located within the South Coast Air Basin (SCAB) and is subject to the guidelines and regulations of the South Coast Air Quality Management District (SCAQMD).

2.3.4.1 South Coast Air Quality Management District
While CARB is responsible for the regulation of mobile emission sources within the State, local AQMDs and APCDs are responsible for enforcing standards and regulating stationary sources. The proposed Project is located within the SCAB and is subject to the guidelines and regulations of the SCAQMD.

The SCAQMD was created by the 1977 Lewis-Presley Act, which merged four county air pollution control bodies (i.e., Los Angeles, Orange, and Riverside Counties, and the non-desert portion of San Bernardino County) into one regional district for the SCAB. In the SCAB, the SCAQMD is the agency responsible for protecting public health and welfare through the administration of federal and State air quality laws, regulations, and policies.

Included in the SCAQMD’s tasks are the monitoring of air pollution, the preparation of the Air Quality Management Plan (AQMP) for the SCAB, and the promulgation of rules and regulations. The AQMP includes strategies and tactics to be used to attain the NAAQS and CAAQS standards in SCAB, whereas the rules and regulations include procedures and requirements to control the emission of pollutants and to prevent adverse impacts.

For the proposed Project area, the Southern California Association of Governments (SCAG) is the federally-designated Metropolitan Planning Organization and the State-designated transportation planning agency for six counties: Riverside, San Bernardino, Los Angeles, Ventura, Imperial, and Orange Counties.

The SCAQMD and SCAG are jointly responsible for preparing the AQMP for the SCAB. In particular, the 2022 AQMP is based on demographic growth forecasts for various socioeconomic categories (e.g., population, housing, employment by industry) developed by SCAG for their 2024 Regional Transportation Plan (RTP), which forms part of SCAG’s 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS).

Thus, consistency with the planning assumptions contained within the RTP/SCS (also known as Connect SoCal) demonstrates consistency with SCAQMD’s 2022 AQMP.45 Additionally, with respect to air quality planning, SCAG has prepared the Regional Comprehensive Plan for the SCAG region, which includes Growth Management and Regional Mobility chapters, which form the basis for the land use and transportation components of the AQMP. These chapters are utilized in the preparation of air quality forecasts and the consistency analysis that is included in the AQMP.
45 SCAG. 2024. 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy. April. Available at:
https://scag.ca.gov/connect-socal. Accessed: October 2025.

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Below is a list of SCAQMD rules relevant to the proposed Project:

SCAQMD Rule 402: Nuisance
Prohibits discharges of air contaminants that causes nuisance to the public.

SCAQMD Rule 403: Fugitive Dust
Regulates fugitive dust emissions from any commercial construction or demolition activity capable of generating fugitive dust emissions, including active operations, open storage piles, and disturbed surface areas, as well as track-out beyond an active operation.

SCAQMD Rule 1113: Architectural Coatings
Requires manufacturers, distributors, and end users of architectural and industrial maintenance coatings to reduce VOC emissions from the use of these coatings, primarily by placing limits on the VOC content of various coating categories.

SCAQMD Rule 1470: Requirements for Stationary Diesel-Fueled Internal Combustion and Other Compression-Ignition Engines
Implements the ATCM for Stationary Compression-Ignition Engines for engines greater than 50 hp. Sets forth requirements to reduce PM emissions and requires off-road engines to meet standards specified in the Off-Road Compression-Ignition Engine Standards.

Establishes additional requirements for engines located in close proximity to existing schools.

AQMP Status
The AQMP and SIP processes generally occur concurrently: The SIP is required under the federal CAA to provide the framework for non-attainment areas to come into attainment of the NAAQS, and the AQMP is prepared by the SCAQMD, in part, to satisfy the requirement for a SIP. The AQMP traditionally evaluates all CAPs; portions of the AQMP represent the required SIP elements, which are then transmitted to CARB for review, approval, and transmittal to the USEPA for inclusion in the overall California SIP.

The SCAQMD has been preparing AQMPs (and related SIP elements) since the 1989 AQMP.

The list below presents the AQMPs prepared by the SCAQMD and a short summary of included SIP elements:
• 1989 AQMP – 1-hour ozone SIP elements.
• 1991 AQMP – 1-hour ozone SIP elements (attainment demonstration). • 1994 AQMP – 1-hour ozone SIP elements designed to forestall a potential Federal Implementation Plan and PM10 SIP elements describing Best Available Control Measures. • 1997 AQMP – PM10 SIP elements (attainment demonstration) and updated 1-hour ozone SIP elements.
• 1999 AQMP – Revisions to 8-hour ozone SIP elements as part of the 1997 AQMP lawsuit settlement agreement.
• 2003 AQMP – Update of some PM10 and 1-hour ozone SIP elements. • 2007 AQMP – New federal standards requiring 8-hour ozone and PM2.5 SIP elements (including new attainment demonstrations and control measures). • 2012 AQMP – New federal 24-hour PM2.5 standard requiring 24-hour PM2.5 SIP elements (attainment demonstration).

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• 2016 AQMP – Update of ozone and PM2.5 SIP elements (including new attainment demonstrations and control measures).
• 2022 AQMP – Includes a variety of new strategies (such as accelerated deployment of available cleaner technologies, etc.) to achieve the 2015 8-hour ozone standard.

As previously mentioned, Table 2-2 shows that Orange County is currently designated as non-attainment for the federal and State O3 standards, the State PM10 standards, and the federal and State PM2.5 standards.46,47
The current status of the AQMPs for these non-attainment pollutants are shown below:
• The 2007 AQMP provides attainment demonstrations for the annual PM2.5 standard by April 5, 2015 and of the 8-hour O3 standard by December 31, 2023; SCAQMD and CARB submitted the amendments to the USEPA. In 2009 and 2011, respectively, at the request of the USEPA, CARB provided clarifying revisions to the annual PM2.5 and 8-hour O3 SIP amendments. In 2011, the USEPA approved the control strategy, emission reduction commitment, and attainment demonstration of the annual PM2.5 standard by April 5, 2015. In 2012, the USEPA approved the control strategy, emission reduction commitment, and attainment demonstration of the annual 8-hour ozone standard by June 15, 2024.48
• The 2012 AQMP provides attainment demonstrations for the 24-hour PM2.5 standard by 2019 and the 1-hour O3 standard by 2023.49,50 In addition, it provides supplemental information for the approved 8-hour ozone SIP. On January 25, 2013, CARB approved the 2012 AQMP, which was subsequently submitted to the USEPA. On September 3, 2014, USEPA issued a final rule approving and promulgating the portions of the SIP revision related to the 1-hour and 1997 8-hour ozone standards.51 In 2015, the SCAQMD prepared a Supplement to the 24-hour PM2.5 SIP to address Subpart 4 provisions and requirements. On February 12, 2018, USEPA issued a final rule approving 46 USEPA. The Green Book Non-Attainment Areas for Criteria Pollutants. Available at:
https://www.epa.gov/green-book. Accessed: October 2025. 47 CARB. Maps of State and Federal Area Designations. Available at: http://www.arb.ca.gov/desig/adm/adm.htm.

Accessed: October 2025.
48 CARB. 2013. South Coast Air Basin 2012 PM2.5 and Ozone State Implementation Plans, Resolution No. 13-3.

January 25. Available at: https://ww3.arb.ca.gov/planning/sip/planarea/scabsip/resolution13-3.pdf. Accessed:

October 2025.
49 SCAQMD. 2012. Air Quality Management Plan. Main Document. December. Available at:
http://www.aqmd.gov/docs/default-source/clean-air-plans/air-quality-management-plans/2012-air-qualitymanagement-plan/final-2012-aqmp-carb-epa-sip-submittal-(december-2012)/2012-aqmp-carb-epa-sipsubmittal-main-document.pdf. Accessed: October 2025. 50 SCAQMD. 2012. Air Quality Management Plan. Appendix VII – 1-hour Ozone Attainment Demonstration.

Available at: http://www.aqmd.gov/docs/default-source/clean-air-plans/air-quality-management-plans/2012- air-quality-management-plan/final-2012-aqmp-carb-epa-sip-submittal-(december-2012)/2012-aqmp-carb-epasip-submittal-appendix-vii.pdf. Accessed: October 2025. 51 USEPA. 2014. Federal Register, Vol. 79, No. 170, Approval and Promulgation of Implementation Plans; California; South Coast 1-Hour and 8-Hour Ozone. Available at: https://www.govinfo.gov/content/pkg/FR-2014- 09-03/pdf/2014-20790.pdf. Accessed: October 2025.

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and promulgating portions of the SIP revision that addressed the requirements for the 2006 24-hour PM2.5 standard.52
• The 2016 AQMP provides attainment demonstrations for the 8-hour O3 standards; 1997 standard (0.08 parts per million [ppm]) by 2023 and 2008 standard (0.075 ppm) by 2031, the 1-hour O3 standard by 2022, 24-hour PM2.5 standard by 2019 and the annual PM2.5 standard by 2025. The SCAQMD adopted the 2016 AQMP on March 3, 2017 and submitted the plan to CARB on March 10, 2017. CARB adopted the 2016 AQMP on March 23, 2017 and submitted it to USEPA as a revision to the California SIP on April 27, 2017. On February 12, 2019, USEPA issued a final rule approving and promulgating portions of SIP revision that addresses the requirements for the 2006 24-hour PM2.5 standard.53
• The 2022 AQMP provides attainment demonstrations for the 2015 8-hour O3 standard (0.07 ppm) by 2037. The SCAQMD adopted the 2022 AQMP on December 2, 2022 and submitted the plan to CARB on December 13, 2022. CARB adopted the 2022 AQMP on January 26, 2023 and submitted it to USEPA as a revision to the California SIP on February 22, 2023.

2.3.4.2 City of Lake Forest
The City of Lake Forest General Plan, adopted June 2020, has land use and design, mobility, economic development, recreation and resources, public safety, public facilities, and health and wellness elements.54 The Recreation and Resources chapter of the General Plan includes Goal RR-4: Air Quality and Greenhouse Gas Emissions, which outline the following policies aimed to improve air quality and reduce greenhouse gas emissions. • RR-4.1: Regional Standards. Coordinate planning efforts with the SCAQMD, SCAG, and CARB to meet local and regional air quality standards and ensure attainment of established goals.
• RR-4.2: Land Use Planning. Utilize land use planning techniques to reduce traffic congestion and promote alternative modes of transportation for the community. • RR-4.3: Development. Encourage and incentivize the development of mixed-use residential opportunities and live-work environments within the City to lessen the impacts of traffic congestion on local air quality.
• RR-4.4: Active Transportation. Improve active transportation options within the City by connecting local bikeways and trails to City bus stops and public transportation centers.
52 USEPA. 2018. Federal Register, Vol. 83, No. 29, Air Quality State Implementation Plans; Approvals and Promulgations: California; South Coast Moderate Area Plan for the 2006 PM2.5 Standards; Correction of Deficiency. Available at: https://www.govinfo.gov/content/pkg/FR-2018-02-12/pdf/2018-02677.pdf.

Accessed: October 2025.
53 USEPA. 2019. Federal Register, Vol. 84, No. 29, Approval and Promulgation of Implementation Plans; California; South Coast Serious Area Plan for the 2006 PM2.5 NAAQS. Available at:
https://www.govinfo.gov/content/pkg/FR-2019-02-12/pdf/2019-01922.pdf. Accessed: October 2025. 54 City of Lake Forest. 2020. General Plan. June. Available at:
https://www.lakeforestca.gov/departments/community_development/planning/plans_and_standard_guidelines.p hp#undefined. Accessed: October 2025.

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• RR-4.5: Public Transit. Coordinate with the Orange County Transportation Authority and actively pursue the improvement and expansion of public transit for Lake Forest residents.
• RR-4.6: Sensitive Receptors. Insulate sensitive receptors from areas of heightened air quality pollution, including highways, by utilizing land use planning to buffer and protect residential areas.
• RR-4.7: Mitigation. Require the implementation of relevant mitigation measures for all future development upon identification of potential air quality impacts. • RR-4.8: Local Reduction Targets. The City of Lake Forest establishes the following per capita GHG reduction targets, in order to meet the requirements established by the state under AB 32 and SB 32, consistent with the CARB’s 2017 Scoping Plan:
− 3.99 MT carbon dioxide equivalent (CO2e) per capita by 2030 − 2.66 MT CO2e per capita by 2040; and
− 1.33 MT CO2e per capita by 2050
• RR-4.9: GHG Reduction. Consider and adopt new policies and programs that will help to provide energy efficient alternatives to fossil fuel use and reduce consumption in order to reduce greenhouse gas emissions.
• RR-4.10: Carbon Reduction. Expand the number of parks and trees in Lake Forest to provide a larger carbon sink or area containing natural sources that retain more carbon than what those sources emit.
• RR-4.11: Public Engagement. Promote regional air quality programs in order to inform the public on regional air quality concerns and encourage the engagement of all Lake Forest residents in future planning decisions related to air quality.

2.4 Environmental Setting

2.4.1 Local Air Quality Monitoring Data
The proposed Project is located within the SCAQMD jurisdiction. The SCAQMD maintains ambient air quality monitoring stations throughout the SCAB. The Saddleback Valley air monitoring station is the station closest to the proposed Project. The Saddleback Valley monitoring station monitors ambient concentrations of CO, O3, PM10, and PM2.5. Ambient concentrations of nitrogen dioxide (NO2) and sulfur dioxide (SO2) are not monitored at the Saddleback Valley monitoring station. The nearest monitoring stations to the Project site that monitor these pollutants are the I-5 Near Road Monitoring Station and the South Coastal LA County 3 Monitoring Station, respectively.

The five most recent years of published data at these monitoring stations at the time of preparation of this report are provided in Table 2-3. The frequency with which O3 and PM standards have been exceeded at the nearest monitoring sites is displayed in Table 2-4.

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3. SIGNIFICANCE THRESHOLDS

3.1 California Environmental Quality Act Guidelines
The analysis provided in this report evaluates the significance of the Project’s CAP emissions by reference to the following questions from Section III, Air Quality, of Appendix G of the California Environmental Quality Act (CEQA) Guidelines:
55 Threshold 1. Would the Project conflict with or obstruct implementation of the applicable air quality plan?
Threshold 2. Would the Project result in a cumulatively considerable net increase of any criteria pollutant for which the Project region is non-attainment under an applicable federal or state ambient air quality standard? Threshold 3. Would the Project expose sensitive receptors to substantial pollutant concentrations?
Threshold 4. Would the Project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
An evaluation of the Project based on the significance thresholds discussed below is provided in subsequent sections.

3.2 South Coast Air Quality Management District Thresholds The SCAQMD has established significance thresholds56 to assess the impacts of project-related construction and operational emissions on regional and local ambient air quality. Table 3-1 shows the mass daily thresholds for construction and operation as adopted by the SCAQMD for CAP and TAC emissions. The analysis summarized in this report estimates project-related construction and operational mass emissions and compares the emissions to these mass daily significance thresholds. This report also evaluates the localized ambient air quality impacts from on-site construction and operational activities (e.g., emissions from off-road construction equipment, area emissions, energy emissions, mobile emissions, and stationary source emissions) using SCAQMD’s localized significance threshold (LST) methodology.57 If emission estimates for the proposed Project activities are below the LST emission levels found in the LST mass look-up tables, the proposed construction or operational activity is not significant for air quality.

The SCAQMD has established significance thresholds to assess health risk impacts of TACs from project-related emissions sources on nearby sensitive receptors including residents and other human populations. A substance released into the air is considered toxic if it has the potential to cause adverse health effects in humans, including increasing the risk of cancer upon exposure, or acute and/or chronic non-cancer health effects. Examples include certain aromatic and chlorinated hydrocarbons, certain metals, and asbestos. TACs are generated by 55 California Natural Resources Agency. 2018. Appendix G of the CEQA Guidelines. Available at:
http://resources.ca.gov/ceqa/docs/2018_CEQA_FINAL_TEXT_122818.pdf. Accessed: October 2025. 56 SCAQMD 2023. South Coast AQMD Air Quality Significance Thresholds. March. Available at:
https://www.aqmd.gov/docs/default-source/ceqa/handbook/south-coast-aqmd-air-quality-significancethresholds.pdf?sfvrsn=25. Accessed: October 2025. 57 SCAQMD. 2008. Final Localized Significance Threshold Methodology. July. Available at:
http://www.aqmd.gov/docs/default-source/ceqa/handbook/localized-significance-thresholds/final-lstmethodology-document.pdf?sfvrsn=2. Accessed: October 2025.

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a number of sources, including stationary sources such as dry cleaners, gas stations, combustion sources, waste processing facilities and laboratories; mobile sources such as automobiles; and area sources such as landfills.

Construction of the Project is estimated to last approximately nine months, and measurable diesel TAC emissions from the Project would occur for only a brief period during construction activities that would require the on-site use of heavy-duty equipment. The SCAQMD does not generally require the analysis of health risk from construction-related diesel emissions, due to the short period for which the majority of diesel exhaust emissions would occur. Based on the scale of the Project and the nature of the Project construction and operational emissions sources, the Project is not expected to generate TAC emissions that would exceed the health risk significance thresholds.

3.3 Project Approach to Significance
This Air Quality Technical Report assesses significance of AQ impacts based on Section III, Air Quality, of Appendix G of the CEQA Guidelines. This Technical Report assessed significance of AQ impacts for Threshold 1 by evaluating the proposed Project for consistency with applicable plans relative to emissions. For Threshold 2, significance was assessed by quantifying the Project’s emissions during construction and operations. These emissions were then compared to applicable SCAQMD thresholds. This report assessed significance for Threshold 3 with a CO hotspots analysis. For Threshold 4, this report evaluates the potential for odor-generating activities from the proposed Project.

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4. AIR QUALITY EMISSIONS INVENTORY
This section describes the methodology that Ramboll used to develop the CAP inventories associated with the Project, which include one-time emissions associated with construction of the Project, and emissions associated with operation of the Project. Construction is assumed to occur October 2026 to June 2027. Emissions due to operation of the Project are quantified for the assumed first year of operations, i.e., 2027. This is a conservative assumption for any future year since mobile source emissions are expected to decrease in future years with the transition of the Statewide mobile source fleet to lower-emitting technologies resulting from the implementation of federal and State mobile source regulations. Sub-categories of operational emissions include the following: area, energy, mobile, and stationary sources.

4.1 Resources

4.1.1 California Emission Estimator Model
Ramboll primarily utilized the California Emissions Estimator Model (CalEEMod) version 2022.1
58 methodology to assist in quantifying the CAP emissions in the inventories presented in this report for the proposed Project. CalEEMod provides methodologies to calculate both construction emissions and operational emissions from a land use development project. It calculates daily or annual CAP emissions. Specifically, the model methodology aids the user in the following calculations:
• One-time short-term construction emissions from off-road construction equipment, and on-road worker, vendor, and hauling vehicles during project construction phases including demolition, site preparation, grading, building construction, paving, and architectural coating.
• Operational emissions associated with the fully built out land use development, such as emissions from traffic generated by the land uses; area sources such as landscaping equipment, architectural coatings, and consumer products; energy sources that use natural gas combustion; and stationary sources such as emergency generators.

CalEEMod is a statewide program designed to calculate CAP emissions from development projects in California developed under the auspices of the SCAQMD, with input from other California air districts, and is currently supported by numerous lead agencies for use in quantifying the emissions associated with development projects undergoing environmental review. CalEEMod utilizes widely accepted models for emission estimates combined with appropriate default data that can be used if site-specific information is not available. These models and default estimates use sources such as the USEPA AP-42 emission factors, 59 CARB’s on-road and off-road equipment emission models such as the EMission FACtor model (EMFAC) and the Emissions Inventory Program model (OFFROAD), and studies commissioned by California agencies such as the California Energy Commission and CalRecycle.
58 CAPCOA. 2022. California Emissions Estimator Model User’s Guide. Version 2022.1. Available at:
https://caleemod.com/user-guide. Accessed: October 2025. 59 The USEPA maintains a compilation of Air Pollutant Emission Factors and process information for several air pollution source categories. The data is based on source test data, material balance studies, and engineering estimates. Available at:
https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors.

Accessed: October 2025.

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As mentioned above, CalEEMod is based upon the CARB approved OFFROAD and EMFAC models. OFFROAD60 is an emission factor model used to calculate emission rates from off-road mobile sources (e.g., construction equipment, agricultural equipment). The off-road diesel emission factors used by CalEEMod are based on the CARB OFFROAD2017 program.

EMFAC is an emission factor model used to calculate emissions rates from on-road vehicles (e.g., passenger vehicles). CalEEMod 2022.1 contains EMFAC2021 emission factors. 61 These
emissions factors were then used to estimate mobile source operational emissions based on CalEEMod methodology and defaults along with Project-specific values where available.

In addition, CalEEMod contains default values and existing regulation methodologies to use in each specific local air district region. Appropriate statewide default values can be utilized if regional default values are not defined. Ramboll used default factors for the Orange County area for the emissions inventory, unless otherwise noted in the methodology descriptions below.

Details regarding the specific methodologies used by CalEEMod can be found in the CalEEMod User’s Guide and associated appendices.62

4.1.2 Other Resources
Where possible, Ramboll utilized Project-specific data to estimate the emissions associated with Project construction and operation. This data (e.g., activity information for construction, and Kittelson & Associates, Inc’s Transportation Impact Study63) was obtained through communication with the Project applicant.

4.2 Construction Emissions
This section describes the calculation of CAP emissions from construction activities at the proposed Project site. While the exact construction schedule and equipment mix may vary from the current analysis, the emissions are not expected to be higher than that calculated given the conservative assumptions included in the analysis.

This analysis includes estimation of CAP emissions from the following major construction phases for the proposed Project:
• Demolition involves removing buildings or structures. • Site Preparation involves clearing vegetation and removing stones and other unwanted material or debris prior to grading.
• Grading involves the cut-and-fill of land to ensure the proper base and slope for the construction foundation.
• Building Construction involves the construction of structures and buildings. • Paving involves the laying of concrete or asphalt such as in parking lots or roads. 60 CARB. 2017. Off Road Mobile Source Emission factors. Available at:
https://ww2.arb.ca.gov/our-work/programs/mobile-source-emissions-inventory. Accessed: October 2025. 61 CARB. 2022. EMFAC2021. Available at: https://ww2.arb.ca.gov/our-work/programs/msei/on-road-emfac.

Accessed: October 2025.
62 CAPCOA. 2022. California Emissions Estimator Model User’s Guide. Version 2022.1. Available at:
https://caleemod.com/user-guide. Accessed: October 2025. 63 Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November.

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• Architectural Coating involves the application of coatings to both the interior and exterior of buildings or structures, and the painting of parking lot striping, associated signage, and curbs.

The proposed schedule for constructing the Project is shown in Table 4-1.

Construction-related emissions of reactive organic gases, NOX, CO, SOX, PM10, and PM2.5 were estimated using CalEEMod. PM emissions are composed of exhaust emissions and fugitive emissions. Exhaust emissions are typically given out by a combustion engine of on-road vehicles and/or off-road equipment. Fugitive emissions are PM dust suspended in the air by wind action and construction-related activities.

The off-road construction equipment list and specifications are based on CalEEMod model defaults, as shown in Table 4-2. The material volumes which are anticipated to be imported and exported for Project construction are presented in Table 4-3. Table 4-4 presents an estimate of the demolition debris that would be generated and shipped offsite during the demolition phase of construction. Lastly, the CalEEMod default worker, vendor, and hauling trips, supplemented with Project-specific information, are displayed in Table 4-5.

4.2.1 Emissions from Construction Equipment
The emission calculations associated with construction equipment are from off-road equipment engine use based on the equipment list and phase length, and on-road vehicle trips and phase length.

Since the majority of the off-road construction equipment used for construction projects are diesel-fueled, CalEEMod methodology assumes all of the equipment operates on diesel fuel.

The calculations include the running exhaust emissions from off-road equipment. Since the equipment is assumed to be diesel, there are no starting emissions associated with the equipment, as these are de minimis for diesel-fueled equipment. CalEEMod calculates the exhaust emissions based on default values for horsepower and load factor from CARB’s OFFROAD2017 methodology using the equation presented below.64 EmissionsDiesel=∑(EFi×Popi×AvgHPi×Loadi×Activityi)
i
Where:

EF = Emission factor in grams per horsepower-hour (g/bhp-hr) as processed from OFFROAD2017
Pop = Population, or the number of pieces of equipment
AvgHp = Maximum rated average horsepower
Load = Load factor
Activity = Hours of operation
i = equipment type
64 CAPCOA. 2022. California Emissions Estimator Model User’s Guide, Appendix C. Available at:
https://caleemod.com/documents/user-guide/04_Appendix%20C.pdf. Accessed: October 2025.

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The construction-related equipment assumptions are based CalEEMod model defaults (Table 4-2). The emissions from the off-road equipment were calculated using CalEEMod, as shown in Appendix A.

4.2.2 Emissions from On-Road Construction Trips
Construction generates on-road vehicle CAP emissions from worker and vendor commuting, concrete trucks, and trucks used for construction debris and soil/material hauling.

These emissions are calculated in CalEEMod based on the number of trips and vehicle miles traveled (VMT) (Table 4-5) along with emission factors from EMFAC2021. The numbers of worker and vendor trips represent defaults from CalEEMod based on the construction equipment to be used. The number of haul trips was estimated by CalEEMod based on the volume of soil to be imported/exported (Table 4-3) and the amount of demolition debris generated (Table 4-4). The number of concrete truck trips was based on Project-specific information.

Additionally, the emissions associated with on-site idling of concrete trucks during the building construction phase were estimated using concrete truck trip rates, idling duration per trip, and emission factors from EMFAC2021. Refer to Table B-1 and Table B-2 in Appendix B for further details.

4.2.3 Fugitive Dust
Fugitive dust contributes to PM10 and PM2.5 emissions and is generated by the various construction activities including entrained road dust, grading, demolition, and truck loading.

Entrained road dust is generated by vehicle travel on paved and unpaved roads. Emission factors for entrained road dust are on a “per mile” basis. In CalEEMod, entrained road dust emission factors are based on the equations presented in the Paved Roads and Unpaved Roads chapters of USEPA’s AP-42 and are then multiplied by the total VMT for project-related trips. Emissions from entrained road dust were estimated using CalEEMod and are presented in Appendix A-1.

Fugitive dust emissions from bulldozing equipment (i.e., rubber-tired dozers), grading equipment (i.e., graders, rubber-tired dozers, and scrapers), and demolition activity occur during the Project construction. In addition, truck loading activities would generate fugitive dust emissions. The construction material movement and demolition assumptions are presented in Table 4-3 and Table 4-4.

Fugitive dust will be controlled by watering the construction site twice daily in accordance with the SCAQMD Rule 403 for fugitive dust control.65 CalEEMod defaults assume watering the construction site twice a day reduces the fugitive dust emissions by 61%. Fugitive dust will also be controlled by watering the demolished area twice daily in accordance with the SCAQMD Rule 403 for fugitive dust control.66 CalEEMod defaults assume watering the demolished area twice a day reduces the fugitive dust emissions by 36%. Emissions from these sources were estimated using CalEEMod and are presented in Appendix A-1. 65 SCAQMD. 2005. Rule 403 – Fugitive Dust. Available at: https://www.aqmd.gov/docs/default-source/rulebook/rule-iv/rule-403.pdf. Accessed: October 2025. 66 Ibid.

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4.2.4 Architectural Coating
Evaporation of solvents contained in architectural coatings that are applied to interior and exterior surfaces of building and used for parking lot painting/striping result in VOC evaporative emissions. CalEEMod was used to estimate these VOC evaporative emissions during Project construction. Emissions from architectural coatings during construction are presented in the CalEEMod model run files shown in Appendix A-1.

4.2.5 Paving
CalEEMod was used to estimate the VOC off-gassing emissions associated with asphalt paving. The emissions associated with paving are presented in the CalEEMod model run files in Appendix A-1.

4.2.6 Total Construction Emissions
The maximum daily CAP emissions associated with construction are summarized in Table 4-9. As shown in this table, the maximum daily CAP emissions are below the SCAQMD mass daily significance thresholds for construction.

4.3 Operational Emissions
This section describes the calculation of CAP emissions from Project operational activities. As noted previously, operational emissions are quantified for the anticipated first year of Project operation, i.e., 2027. The following sub-sections describe the methodologies used to estimate emissions from the following operational source categories: area, energy, mobile, and stationary.

4.3.1 Area Sources
Area sources are those emission sources that are generally too small to be uniquely identified as point sources and are thus generally aggregated as a group. CalEEMod estimates emissions for the following sources under the category of “area” sources:
landscaping equipment (e.g., lawn mowers), consumer products, and architectural coatings.

CAP emissions due to natural gas combustion in buildings, could also be considered area sources, but are reported by CalEEMod in the emissions associated with building energy use (described below).

The CAP emissions generated by the proposed Project conditions were calculated using CalEEMod® defaults and can be viewed in Appendix A-1.

4.3.2 Energy Sources
CAP emissions are emitted from buildings as a result of activities that typically rely on natural gas as an energy source. Ramboll utilized CalEEMod default assumptions to calculate the annual natural gas use for the proposed Project’s land uses, which includes natural gas usage from water heating, primary heating, cooking, cooling, refrigeration, and other miscellaneous end uses. Direct CAP emissions are not associated with electricity usage.

To estimate CAP emissions from the natural gas usage for the proposed Project, Ramboll utilized CalEEMod default assumptions, which incorporate 2019 Title 24 Standards.

The energy use and corresponding CAP emissions for the proposed Project are provided in the CalEEMod output file in Appendix A-1.

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4.3.3 Stationary Sources
The proposed Project includes one compressed natural gas (CNG)-powered emergency generator, rated at 95 horsepower, to support warehouse operations. Testing and maintenance of the generator would remain below 200 hours per year67 or 1 hour on any given day (Table 4-8). Emission factors for the CNG-powered emergency generator were based on CalEEMod defaults and Project-specific information which are summarized in Table C-5 in Appendix C. The resulting CAP emission estimates are provided in the CalEEMod output file in Appendix A-1.

4.3.4 Mobile Sources
The CAP emissions associated with on-road mobile sources are generated from customer and employee vehicles, and delivery trucks (i.e., warehouse and tire center delivery trucks), and TRUs that are mounted on the trailers of some warehouse delivery trucks traveling to and from the Project site. The AQ emissions associated with on-road vehicles include running, idling and starting exhaust emissions, evaporative emissions, tire wear, brake wear, and entrained road dust. Running emissions are dependent on VMT. Starting and evaporative emissions are associated with the number of starts or time between vehicle uses and the assumptions used in determining these values are described below. Exhaust emissions from TRUs are dependent on the operational duration of TRUs. Ramboll calculated mobile source emissions using trip rates based on analyses conducted by Kittelson68 and Project-specific information for warehouse and tire center delivery trucks.

The analysis includes the benefit of reductions from adopted regulatory programs that are accounted for within EMFAC2021 including Assembly Bill 1493 (“the Pavley Standard”), the ACC program, the USEPA/NHTSA Advanced Fuel Economy, the HD I/M program, and the Heavy-Duty Omnibus Regulation. While EMFAC2021 incorporates reductions associated with the ACT regulation, this analysis assumes that all project-related delivery trucks are diesel-fueled. Hence, Public Law 119-15’s disapproval of California’s CAA waiver for the ACT regulation69 does not impact this analysis. Additionally, EMFAC2021 does not include the ACC II regulation;70 therefore, AQ reductions associated with this regulation are not included in this analysis.
67 Per SCAQMD Rule 1110.2, emergency standby engines must not operate more than 200 hours a year. 68 Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November. 69 United States Code. 2025. Public Law 119-15 - Joint resolution providing congressional disapproval under chapter 8 of title 5, United States Code, of the rule submitted by the Environmental Protection Agency relating to "California State Motor Vehicle and Engine Pollution Control Standards; Heavy-Duty Vehicle and Engine Emission Warranty and Maintenance Provisions; Advanced Clean Trucks; Zero Emission Airport Shuttle; Zero-Emission Power Train Certification; Waiver of Preemption; Notice of Decision". Available at:
https://www.govinfo.gov/app/details/PLAW-119publ15. Accessed: October 2025. 70 United States Code. 2025. Public Law 119-16 - Joint resolution providing congressional disapproval under chapter 8 of title 5, United States Code, of the rule submitted by the Environmental Protection Agency relating to "California State Motor Vehicle and Engine Pollution Control Standards; Advanced Clean Cars II; Waiver of Preemption; Notice of Decision". Available at: https://www.govinfo.gov/app/details/PLAW-119publ16.

Accessed: October 2025.

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4.3.4.1 Estimating Mobile Source Emissions
Mobile source emissions calculation requires trip rates, trip lengths, and idle time for each on-road vehicle trip type associated with the proposed Project (e.g., customer and employee vehicles and delivery trucks). Additionally, the operational time for TRU engines that are mounted on some of the trailers delivered to the warehouse is required to estimate exhaust emissions from TRUs. The following sections describe the methodology to derive the necessary inputs for these calculations.
a) On-Road Vehicle Trip Generation Rates
The total trip generation rates for customer and employee vehicles were calculated as the sum of Project trip generation and latent demand trip generation estimates provided by Kittelson (Table 4-6).
71 The number of TRU equipped trailers that are brought on-site by warehouse delivery trucks and the trip generation rates for warehouse and tire center delivery trucks are based on Project-specific estimates, and presented in Appendix C. b) Vehicle Miles Traveled
The VMT of customer and employee vehicles was provided by Kittelson.72 As shown in Table 4-6, the Project VMT for customer and employee vehicles would be negative due to a shift in primary warehouse trips from existing Costco locations. 73 The VMT of delivery trucks
is calculated as the product of trip rates and trip lengths (Table 4-6). The trip length for delivery trucks is based on Project-specific estimates. c) Fleet Mix
The CalEEMod default fleet mix for customer and employee vehicles was adjusted using the default VMT distribution for vehicle technology/fuel categories in EMFAC2021 for Orange County to determine the Project-specific fleet mix of the vehicles visiting the Project (Table C-1 in Appendix C). Customer and employee vehicles primarily represent vehicles used by patrons and employees of the warehouse and include gasoline, plug-in hybrid, electricity, natural gas, and diesel-fueled vehicles. This analysis assumed that customer and employee vehicles did not include heavy heavy-duty trucks or buses. All delivery trucks were assumed to be diesel-fueled heavy heavy-duty trucks.
71 Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November. 72 Ibid.
73 Please see the Foothill Ranch Costco Focused Transportation Impact Study (Kittelson & Associates, November, 2025) for further details.

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d) Mobile Source Emission Factors
Default EMFAC2021 emission factors for the year 2027 were used for customer and employee vehicles. The CalEEMod run for customer and employee vehicles is presented in Appendix A-1.

Delivery truck emission factors for diesel-fueled heavy heavy-duty trucks were obtained from the default EMFAC2021 output for Orange County – South Coast for the year 2027. Refer to Table C-2 in Appendix C for further details. The CalEEMod run for delivery trucks is presented in Appendix A-2.

Exhaust emission factors for TRUs were calculated using OFFROAD2021 outputs for in-State and out-of-State trailer TRUs operating in Orange County as shown in Table C-3 in Appendix C.
e) TRU Operational Time
The total operational time for each TRU equipped trailer that is brought on-site by a warehouse delivery truck is estimated as the sum of the on-site truck idling time and the travel time for the truck round trip (Table C-4 in Appendix C). Daily operational duration of TRUs was estimated based on total operational time per transport refrigeration unit and the total number of TRUs visiting the Project site on a daily basis. Refer to Table C-4 in Appendix C for further details.

4.3.4.2 Mobile Source Emissions
The daily CAP emissions from mobile sources are calculated as the sum of mobile emissions from customer and employee vehicles (presented in Appendix A-1), delivery trucks (presented in Appendix A-2), and TRUs (calculated using OFFROAD2021 emissions output in Table C-4 in Appendix C). These are summarized in Table 4-10.

4.3.5 Total Operational Emissions
Table 4-10 summarizes the total CAP emissions for the proposed Project. Area, energy, mobile, and stationary source emissions were estimated using CalEEMod® (Appendix A-1 and Appendix A-2) except for TRU emissions, which were calculated separately in Table C-4 in Appendix C.

As shown in Table 4-10, the maximum daily emissions of all CAPs (VOC, NOX, CO, SOX, PM10, and PM2.5) are below SCAQMD’s mass daily significance thresholds for operation.

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5. CO HOTSPOTS
Mobile source impacts occur on two basic scales of motion. Regionally, project-related travel will add to regional trip generation and increase the VMT within the local airshed and the SCAB. Locally, Project traffic will be added to the City’s roadway system. There is a potential for the formation of microscale CO “hotspots” in the area immediately around points of congested traffic. Because of continued improvement in mobile emissions at a rate faster than the rate of vehicle growth and/or congestion, the potential for CO hotspots in the basin is steadily decreasing.

Projects contributing to adverse traffic impacts may result in the formation of CO hotspots.

To verify that the proposed Project would not cause or contribute to a violation of the CO standard, a screening evaluation of the potential for CO hotspots was conducted. The potential for CO hotspots was evaluated based on the results of the Kittleson traffic analysis.

Project Evaluation
Based on the analysis below, the proposed Project would not result in a CO “hot spot” and a CO “hot spots” analysis is not needed to determine whether the change in the level of service of an intersection in the proposed Project area would have the potential to result in exceedances of the CAAQS or NAAQS or expose sensitive receptors to substantial pollutant concentrations.

It has long been recognized that CO exceedances are caused by vehicular emissions,74 primarily when idling at intersections.75,76 Accordingly, vehicle emissions standards have become increasingly more stringent. Before the first vehicle emission regulations, cars in the 1950s were typically emitting about 87 grams of CO per mile.77 Since the first regulation of CO emissions from vehicles (model year 1966) in California, vehicle emissions standards for CO applicable to light-duty vehicles have decreased by 96% for automobiles,78,79 and new cold weather CO standards have been implemented, effective for the 1996 model year.80 Currently, the CO standard in California is a maximum of 4.2 grams/mile for passenger cars (with provisions for certain cars to emit less).81
74 USEPA. 2000. Air Quality Criteria for Carbon Monoxide. EPA 600/P-099/001F. June. 75 SCAQMD. 1993. CEQA Air Quality Handbook. Section 4.5. April. 76 SCAQMD. 2003. Air Quality Management Plan. August. Available at: https://www.aqmd.gov/home/airquality/clean-air-plans/air-quality-mgt-plan/2003-aqmp. Accessed: October 2025. 77 USEPA. Timeline of Major Accomplishments in Transportation, Air Pollution, and Climate Change. Available at:
https://www.epa.gov/transportation-air-pollution-and-climate-change/timeline-major-accomplishmentstransportation-air. Accessed: October 2025. 78 National Academy Board on Energy and Environmental Systems. 2008. Review of the 21st Century Truck Partnership. Appendix D: Vehicle Emission Regulations [excerpt from. Available at:
http://books.nap.edu/openbook.php?record_id=12258&page=107] Accessed: October 2025. 79 Kavanagh, Jason. 2008. Untangling U.S. Vehicle Emissions Regulations. 80 Title 13. California Code of Regulations. Section 1960.1(f)(2) [for 50,000 mile half-life]. 81 CARB. 2018. California 2015 and Subsequent Model Criteria Pollutant Exhaust Emission Standards and Test Procedures and 2017 and Subsequent Model Greenhouse Gas Exhaust Emission Standards and Test Procedures for Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles. December 19. Available at:
http://ww2.arb.ca.gov/sites/default/files/2020-
02/ldtps_2015%2B%20CP%20or%202017%2B%20GHG%20MY_lev%20iii_clean%20complete_4- 19_accessible.pdf. Accessed: October 2025.

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With the turnover of older vehicles, introduction of cleaner fuels and implementation of control technology on industrial facilities, CO concentrations in the SCAQMD have steadily declined.

The analysis prepared for CO attainment in the SCAB by the SCAQMD can be used to assist in evaluating the potential for CO exceedances in the SCAB. CO attainment was thoroughly analyzed as part of the SCAQMD’s 2003 Air Quality Management Plan (2003 AQMP) and the 1992 Federal Attainment Plan for Carbon Monoxide (1992 CO Plan).82 As discussed in the 1992 CO Plan, peak CO concentrations in the SCAB are due to unusual meteorological and topographical conditions, and not due to the impact of particular intersections. Considering the region’s unique meteorological conditions and the increasingly stringent CO emissions standards, CO modeling was performed as part of 1992 CO Plan and subsequent plan updates and air quality management plans.

In the 1992 CO Plan, a CO hot spot analysis was conducted for four busy intersections in Los Angeles at the peak morning and afternoon time periods. The intersections evaluated included: Long Beach Blvd. and Imperial Highway (Lynwood); Wilshire Blvd. and Veteran Ave. (Westwood); Sunset Blvd. and Highland Ave. (Hollywood); and La Cienega Blvd. and Century Blvd. (Inglewood). These analyses did not predict a violation of CO standards. The busiest intersection evaluated was that at Wilshire Blvd. and Veteran Ave., which has a daily traffic volume of approximately 100,000 vehicles per day. The 2003 AQMP estimated that the 1-hour concentration for this intersection was 4.6 ppm, which indicates that the most stringent 1-hour CO standard (20.0 ppm) would likely not be exceeded until the daily traffic at the intersection exceeded more than 400,000 vehicles per day.83
Figures 12 and Figure 13 from the Kittelson Transportation Impact Study include existing with Project peak hour traffic volumes for the main roadway intersections around the proposed Project.84 Figures 12 and 13 from the Transportation Impact Study show that the highest peak hourly traffic volumes would be approximately 4,863 vehicles at the intersection of Portola Parkway, El Toro Road, and Santa Margarita Parkway for weekdays and approximately 3,919 vehicles at the same intersection for Saturdays. Even if these trips happened at every hour of the day, both Project trips and non-Project trips will be well below 400,000 vehicles per day at the intersection with the highest daily traffic volumes.

Figure 16 and Figure 17 from the Kittelson Traffic Transportation Impact Study include projected “with Project peak hour” traffic volumes for the main roadway intersections around the proposed Project.85 Figures 16 and 17 from the Transportation Impact Study show that the highest peak hourly traffic volumes would be approximately 5,201 vehicles at the intersection of Portola Parkway, El Toro Road, and Santa Margarita Parkway for weekdays and approximately 4,178 vehicles at the same intersection for Saturdays. Even if these trips happened at every hour of the day, both Project trips and non-Project trips will still be below 400,000 vehicles per day at the busiest intersection.
82 SCAQMD. 2005. Federal Attainment Plan for Carbon Monoxide. Carbon Monoxide Redesignation Request and Maintenance Plan. February. Available at:
http://www.arb.ca.gov/planning/sip/sccosip05/sccosip_redesig_mplan.pdf. Accessed: October 2025. 83 Based on the ratio of the CO standard (20.0 ppm) and the modeled value (4.6 ppm). 84 Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November. 85 The Kittelson Traffic Impact Study assumed a buildout year of 2028 whereas the AQ Technical Report conservatively assumed a buildout year of 2027 based on the last day of construction.

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There is no reason unique to SCAB meteorology to conclude that the CO concentrations at the proposed Project intersections would exceed the 1-hour CO standard if modeled in detail, based on the studies undertaken for the 2003 AQMP.

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6. PROJECT INVENTORY IN CONTEXT
This section assesses the significance of the proposed Project’s emissions for purposes of CEQA.

6.1 Threshold 1: Would the Project conflict with or obstruct implementation of the applicable air quality plan?
As discussed in Section 2.3, the most current air quality plan for the region is the SCAQMD 2022 AQMP,
86 which is based on demographic growth forecasts for various socioeconomic categories developed by SCAG for their 2024-2050 RTP/SCS. Thus, consistency with the planning assumptions contained within the RTP/SCS demonstrates consistency with SCAQMD’s 2022 AQMP.

The SCAG RTP is a long-range transportation plan that is developed and updated by SCAG every four years. The RTP provides a vision for transportation investments throughout the region. Using growth forecasts and economic trends that project out over a 25-year period, the RTP considers the role of transportation in the broader context of economic, environmental, and quality-of-life goals for the future, identifying regional transportation strategies to address our mobility needs. The SCS is a required element of the RTP. The SCS integrates land use and transportation strategies that will achieve CARB emissions reduction targets.87
The proposed Project would not create any overall population growth; therefore, it has no effect on the growth assumptions used in the 2022 AQMP and 2024-2050 RTP/SCS, Connect SoCal. Additionally, the proposed Project would include Project features related to stationary and mobile sources that support aspects of the current 2022 AQMP. • Transportation Electrification: The Project will include 12 direct current fast charging (DCFC) chargers for plug-in electric vehicles as part of the Project design.

This supports the 2022 AQMP goal of transitioning to cleaner fuels and achieving NOX reductions through greater usage of mobile zero emission technologies by providing a convenient, low-cost EV charging station to members which would in turn replace conventionally fueled VMT with electric miles traveled. This supports measures within the 2022 AQMP that focus on accelerating the deployment of zero emission infrastructure needed for the widespread adoption of zero emission vehicles and equipment.
• VMT Reduction: The traffic analysis for this Project88 found that the Project would result in a net reduction in VMT across the region. Furthermore, the Project is expected to serve the existing population of the area by providing more convenient access to Costco services. The Project will be located in a central location that will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service.

Additionally, the Project would be an infill development located near existing 86 SCAQMD. 2022. 2022 Air Quality Management Plan. December. Available at:
https://www.aqmd.gov/docs/default-source/clean-air-plans/air-quality-management-plans/2022-air-qualitymanagement-plan/final-2022-aqmp/final-2022-aqmp.pdf. Accessed: November 2025. 87 SCAG. 2024. 2024-2050 Regional Transportation Plan/Sustainable Communities Strategy. April. Available at:
https://scag.ca.gov/connect-socal. Accessed: October 2025. 88 Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November.

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commercial developments and would therefore support the preservation of natural and working lands and compact infill development. This supports the Transportation Control Measures of the 2022 AQMP which are generally designed to reduce VMT as included in SCAG RTP.
• Energy Efficiency: The Project will implement a number of measures to reduce energy usage and will incorporate sustainability features per the California Title 24 energy requirements. The Project will meet the California Green Building Code requirements which include a number of green building practices to reduce energy use. These practices are listed below and support the 2022 AQMP goal of achieving co-benefits from existing commercial building energy efficiency measures:
o Parking lot light standards are designed in order to provide even light distribution, and utilize less energy compared to a greater number of fixtures at lower heights. The use of light emitting diode (LED) lamps provides a higher level of perceived brightness with less energy than other lamps such as high pressure sodium.
o New and renewable building materials are typically extracted and manufactured within the region.
o The use of pre-manufactured building components, including structural framing and metal panels, helps to minimize waste during construction. o Pre-manufactured metal wall panels with insulation carry a higher R-Value and greater solar reflectivity to help conserve energy. Building heat absorption is further reduced by a decrease in the thermal mass of the metal wall when compared to a typical masonry block wall.
o Costco uses a reflective cool roof material to produce lower heat absorption and thereby lowering energy requirements during the hot summer months.

This roofing material meets the requirements for the EPA’s Energy Star energy efficiency program.
o The irrigation system includes the use of deep root watering bubblers for parking lot trees to minimize usage and ensure that water goes directly to the intended planting areas.
o Storm water management plans are designed to maintain quality control and storm water discharge rates.
o Use of native species vegetation and drip irrigation systems greatly reduces potable water consumption.
o High-efficiency restroom fixtures achieve a 40% decrease and water savings over U.S. standards by using high-efficient restroom fixtures. o Commissioning of mechanical systems to ensure the system is functioning as designed.
o Heating, ventilation, and air conditioning (HVAC) comfort systems are controlled by a computerized building management system to maximize efficiency.
o HVAC units are high-efficiency direct ducted units.

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o HVAC units have phased out the use of hydrochlorofluorocarbons completely.

Long before the Montreal Protocol timeline.
o Parking lot and exterior lights are controlled by a centrally controlled Energy Management system.
o Lighting is controlled by the overall Project energy management system. o High-efficiency light source and ballasts (LED) and bi-level switching for fluorescent fixtures are used.
o Energy efficient Transformers.
o Use of variable speed motors on make-up air units and booster pumps. o Gas water heaters are direct vent and 94% efficient or greater. o Main Building structure is a pre-engineered system that uses 100% recycled steel materials and is designed to minimize the amount of material utilized. o Roof material is recycled standing seam metal panel, designed to maximum efficiency for spanning the structure.
o When masonry and concrete are used, the materials purchased are local to the Project minimizing the transportation and impact to local road networks. o Construction waste is recycled whenever possible.
o Floor sealant is No-VOC and represents over 80% of the floor area. o CO2 is monitored throughout the warehouse.
o Extensive recycling/reuse program is implemented for warehouse and office space including tires, cardboard, grease, plastics and electronic waste. o Use of plastic shopping bags is avoided.
o Suppliers are required to reduce packaging and consider alternative packaging solutions.
o Distribution facilities are strategically located to minimize miles traveled for delivery. Deliveries are made in full trucks.
o All Costco trucks are equipped with an engine idle shut off timer. • Renewable Energy Generation: The Project will install solar panels which will generate renewable electricity and will displace some of the electricity used by the Project, decreasing the average carbon intensity of the electricity used by the Project. This would support the 2022 AQMP goal of encouraging renewables such as solar thermal and photovoltaics.

The Project is consistent with these plans and would not impair the region’s ability to achieve the SCAQMD’s goals for attainment of air quality standards, thus the proposed Project would not conflict with or obstruct implementation of the SCAQMD 2022 AQMP nor the SCAG RTP/SCS.

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6.2 Threshold 2: Would the Project result in a cumulatively considerable net increase of any criteria pollutant for which the Project region is non-attainment under an applicable federal or state ambient air quality standard?
The proposed Project is located within Orange County, which is currently designated as non-attainment for the federal and State O3 standards, the State PM10 standards, and the federal and State PM2.5 standards. Ozone precursors include VOC and NOX. As discussed in Section 4, estimated emissions for the proposed Project show that the maximum daily mass emissions for construction (Table 4-9) and the maximum daily mass emissions for operations (Table 4-10) are less than the SCAQMD mass daily significance thresholds for all CAPs. Therefore, the proposed Project would not result in cumulatively considerable impacts for CAPs for which the Project region is non-attainment.

The SCAQMD’s LST Methodology was used to evaluate localized ambient air quality impacts from on-site construction (e.g., emissions from on-site off-road construction equipment, material movement, demolition, and construction vehicle (worker/vendor/haul) travel) and on-site operational activities (e.g., mobile emissions from trucks and passenger vehicles, area emissions, and energy emissions), and whether the proposed Project would expose sensitive receptors to substantial pollutant concentrations. SCAQMD’s LST Methodology is recommended for projects that are less than or equal to five acres. When assuming a size of five acres, the maximum daily on-site emissions from Project construction and operation are below the SCAQMD LST thresholds (shown in Table 6-1). Since the SCAQMD LST thresholds become more stringent with decreasing project area, the Project, which has a site area of

16.3 acres, would have a less than significant impact on localized ambient air quality.

6.3 Threshold 3: Would the Project expose sensitive receptors to substantial pollutant concentrations?

6.3.1 Localized Significance Thresholds
The SCAQMD’s LST Methodology was used to evaluate localized ambient air quality impacts from on-site construction (e.g., emissions from on-site off-road construction equipment, material movement, demolition, and construction vehicle (worker/vendor/haul) travel) and on-site operational activities (e.g., mobile emissions from trucks and passenger vehicles, area emissions, and energy emissions), and whether the proposed Project would expose sensitive receptors to substantial pollutant concentrations. SCAQMD’s LST Methodology is recommended for projects that are less than or equal to five acres. When assuming a size of five acres, the maximum daily on-site emissions from Project construction and operation are below the SCAQMD LST thresholds (shown in Table 6-1). Since the SCAQMD LST thresholds become more stringent with decreasing project area, the Project, which has a site area of

16.3 acres, would have a less than significant impact on localized ambient air quality.

6.3.2 Localized Carbon Monoxide Impacts
Per Section 5, the proposed Project would not result in a localized CO “hot spot” and is therefore not expected to have the potential to result in exceedances of the CAAQS/NAAQS or expose sensitive receptors to substantial pollutant concentrations.

6.3.3 Health Risk
The SCAQMD has established significance thresholds to assess health risk impacts of TACs from project-related emissions sources on nearby sensitive receptors including residents and other human populations. A substance released into the air is considered toxic if it has the Item: 11
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potential to cause adverse health effects in humans, including increasing the risk of cancer upon exposure, or acute and/or chronic non-cancer health effects. Examples include certain aromatic and chlorinated hydrocarbons, certain metals, and asbestos. TACs are generated by a number of sources, including stationary sources such as dry cleaners, gas stations, combustion sources, waste processing facilities and laboratories; mobile sources such as automobiles; and area sources such as landfills.

Construction of the Project is estimated to last approximately nine months, and measurable diesel TAC emissions from the Project would occur for only a brief period during construction activities that would require the on-site use of heavy-duty equipment. The SCAQMD does not generally require the analysis of health risk from construction-related diesel emissions, due to the short period for which the majority of diesel exhaust emissions would occur.

Based on the nature of the Project construction and operational emissions sources, the Project is not expected to generate TAC emissions that would exceed the health risk significance thresholds.

6.4 Threshold 4
Would the Project result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
According to the SCAQMD, land uses associated with odor complaints typically include agricultural uses, wastewater treatment plants, food processing plants, chemical plants, composting, refineries, landfills, dairies, and fiberglass molding.89 The proposed Project will include potential sources of odor from trash bins and the disposal of food waste from the food court. However, these odor sources are not expected to differ from the typical waste and odor of a retail area. Therefore, the proposed Project would not result in odors adversely affecting a substantial number of people.

Construction activities associated with potential odors include equipment exhaust (i.e., from off-road construction equipment), paving, and architectural coating. There are no unusual Project characteristics or construction processes that would require the use of equipment that would be more fuel intensive than is used for comparable construction activities, nor equipment that would not conform to current emissions standards. It is expected that these impacts would be short-term in duration and typical of comparable activities, therefore the impacts would not adversely affect a substantial number of people and would be less than significant.
89 SCAQMD. CEQA Air Quality Handbook. Available at: https://www.dtscssfl.com/files/lib_ceqa/ref_draft_peir/Chap4_2-AirQuality/SCAQMD_1993_-_CEQA_Handbook.pdf. Accessed:

October 2025.

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TABLES
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Table 2-1. Summary of National and California Ambient Air Quality Standards Costco Foothill Ranch
Lake Forest, California
DRAFT
Concentration3 Method4 Primary3,5 Secondary3,6 Method7
1 Hour 0.09 ppm
(180 µg/m3
) -
8 Hour 0.070 ppm
(137 µg/m3
)

0.070 ppm
(137 µg/m3)
24 Hour 50 µg/m3 150 µg/m3
Annual Arithmetic
Mean 20 µg/m3 -
24 Hour - - 35 µg/m3 Same as Primary
Standard
Annual Arithmetic
Mean 12 µg/m3 Gravimetric or Beta Attenuation 9.0 µg/m3 15.0 µg/m3 1 Hour 20 ppm
(23 mg/m3
)
35 ppm
(40 mg/m3) -
8 Hour 9.0 ppm
(10 mg/m3
)
9 ppm
(10 mg/m3) -
8 Hour (Lake Tahoe) 6 ppm
(7 mg/m3
) --
1 Hour 0.18 ppm
(339 µg/m3
)
100 ppb
(188 µg/m3) -
Annual Arithmetic
Mean

0.030 ppm
(57 µg/m3
)
53 ppb
(100 µg/m3)
Same as Primary
Standard
1 Hour 0.25 ppm
(655 µg/m3
)
75 ppb
(196 µg/m3)
3 Hour - - 0.5 ppm
(1300 µg/m3
)
24 Hour 0.04 ppm
(105 µg/m3
)

0.14 ppm
(for certain
areas)11
-
Annual Arithmetic
Mean -

0.030 ppm
(for certain
areas)11
-
30 Day Average 1.5 µg/m3 --
Calendar Quarter -

1.5 µg/m3
(for certain
areas)12
Rolling 3-Month
Average - 0.15 µg/m3
Visibility Reducing
Particles14 8 Hour See footnote 14
Beta Attenuation and
Transmittance
through Filter Tape
Sulfates 24 Hour 25 µg/m3 Ion Chromatography
Hydrogen Sulfide 1 Hour 0.03 ppm
(42 µg/m3
)
Ultraviolet
Fluorescence
Vinyl Chloride12 24 Hour 0.01 ppm
(26 µg/m3
) Gas Chromatography
Notes:

Pollutant Averaging Time
California Ambient Air Quality
Standards (CAAQS)1
National Ambient Air Quality Standards
(NAAQS)2
Ozone (O3)
8 Ultraviolet
Photometry
Same as Primary
Standard Ultraviolet Photometry
Respirable Particulate
Matter (PM10)
9 Gravimetric or Beta
Attenuation
Same as Primary
Standard
Inertial Separation and
Gravimetric Analysis
Fine Particulate
Matter (PM2.5)
9 Inertial Separation and
Gravimetric Analysis
No National Standards
1 California standards for ozone, carbon monoxide (except 8-hour Lake Tahoe), sulfur dioxide (1 and 24 hour), nitrogen dioxide, and particulate matter (PM10, PM2.5, and visibility reducing particles), are values that are not to be exceeded. All others are not to be equaled or exceeded. California ambient air quality standards are listed in the Table of Standards in Section 70200 of Title 17 of the California Code of Regulations.

Carbon Monoxide
(CO)
Non-Dispersive
Infrared Photometry
(NDIR)
Non-Dispersive Infrared
Photometry (NDIR)
Nitrogen Dioxide
(NO2)
10 Gas Phase
Chemiluminescence
Gas Phase
Chemiluminescence
Sulfur Dioxide (SO2)
11 Ultraviolet
Fluorescence
Ultraviolet
Fluorescence;
Spectrophotometry
(Pararosaniline Method)
Lead (Pb)12,13 Atomic Absorption High Volume Sampler
and Atomic Absorption Same as Primary
Standard
5 Primary NAAQS: The levels of air quality necessary, with an adequate margin of safety to protect public health. 6 Secondary NAAQS: The levels of air quality necessary to protect public welfare from any known or anticipated adverse effects of a pollutant. 8 On October 1, 2015, the national 8-hour ozone primary and secondary standards were lowered from 0.075 to 0.070 ppm. 2 National standards (other than ozone, particulate matter, and those based on annual arithmetic mean) are not to be exceeded more than once a year. The ozone standard is attained when the fourth highest 8-hour concentration measured at each site in a year, averaged over three years, is equal to or less than the standard. For PM10, the 24-hour standard is attained when the expected number of days per calendar year with a 24-hour average concentration above 150 μg/m3
is equal to or less than one. For PM2.5, the 24-hour standard is attained when 98 percent of the daily concentrations, averaged over three years, are equal to or less than the standard. Contact the USEPA for further clarification and current national policies.
4 Methods specified by the CARB or any equivalent measurement method which can be shown to the satisfaction of the CARB to give equivalent results at or near the level of the air quality standard may be used. 7 Reference method as described by the USEPA. An “equivalent method” of measurement may be used but must have a “consistent relationship to the reference method” and must be approved by the USEPA.
9 On February 7, 2024, the national annual PM2.5 primary standard was lowered from 12.0 μg/m3 to 9.0 μg/m3. The existing national 24-hour PM2.5 standards (primary and secondary) were retained at 35 μg/m3, as was the annual secondary standard of 15 μg/m3. The existing 24-hour PM10 standards (primary and secondary) of 150 μg/m3 also were retained. The form of the annual primary and secondary standards is the annual mean, averaged over 3 years.
3 Concentration expressed first in units in which it was promulgated. Equivalent units given in parentheses are based upon a reference temperature of 25°C and a reference pressure of 760 torr. Most measurements of air quality are to be corrected to a reference temperature of 25°C and a reference pressure of 760 torr; ppm in this table refers to parts per million (ppm) by volume, or micromoles of pollutant per mole of gas.

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Table 2-1. Summary of National and California Ambient Air Quality Standards Costco Foothill Ranch
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DRAFT
Notes (Continued):
μg/m3 - micrograms per cubic meter
°C - degrees Celsius
CARB - California Air Resources Board
mg/m3
- milligrams per cubic meter
USEPA - United States Environmental Protection Agency
Abbreviations:
10 To attain the 1-hour national standard, the 3-year average of the annual 98th percentile of the 1-hour daily maximum concentrations at each site must not exceed 100 ppb. Note that the national 1-hour standard is in units of parts per billion (ppb). California standards are in units of parts per million. To directly compare the national 1-hour standard to the California standards the units can be converted from ppb to ppm. In this case, the national standard of 100 ppb is identical to 0.100 ppm. 11 On June 2, 2010, a new 1-hour national SO2 standard was established and the existing 24-hour and annual primary standards were revoked. To attain the 1-hour national standard, the 3-year average of the annual 99th percentile of the 1-hour daily maximum concentrations at each site must not exceed 75 ppb. The 1971 SO2 national standards (0.14 ppm 24-hour standard and 0.030 ppm annual standard) remain in effect until one year after an area is designated for the 2010 standard, except in areas designated nonattainment for the 1971 standards, where the 1971 standards remains in effect until implementation plans to attain or maintain the 2010 standards are approved. Note that the 1-hour national standard is in units of ppb. California standards are in units of ppm. To directly compare the 1-hour national standard to the California standard the units can be converted to ppm. In this case, the national standard of 75 ppb is identical to 0.075 ppm. 12 CARB has identified lead and vinyl chloride as 'toxic air contaminants' with no threshold level of exposure for adverse health effects determined.

These actions allow for the implementation of control measures at levels below the ambient concentrations specified for these pollutants. 13 The national standard for lead was revised on October 15, 2008 to a rolling 3-month average. The 1978 lead standard (1.5 μg/m3 as a quarterly
average) remains in effect until one year after an area is designated for the 2008 standard, except in areas designated nonattainment for the 1978 standard, where the 1978 standard remains in effect until implementation plans to attain or maintain the 2008 standard are approved. 14 In 1989, the CARB converted both the general statewide 10-mile visibility standard and the Lake Tahoe 30-mile visibility standard to instrumental equivalents, which are "extinction of 0.23 per kilometer" and "extinction of 0.07 per kilometer" for the statewide and Lake Tahoe Air Basin standards, respectively.

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Table 2-2. National and California Ambient Air Quality Standard Attainment Status Costco Foothill Ranch
Lake Forest, California
DRAFT
California Ambient Air
Quality Standard (CAAQS)2
National Ambient Air
Quality Standard (NAAQS)3
1 hour Nonattainment -
8 hour Nonattainment Nonattainment ("extreme")
24 hour Nonattainment Attainment (Maintenance)
Annual Nonattainment -
24 hour - Nonattainment ("serious")
Annual Nonattainment Nonattainment ("serious")4
1 hour Attainment Attainment (Maintenance)
8 hour Attainment Attainment (Maintenance)
1 hour Attainment Unclassifiable/Attainment
Annual Attainment Attainment (Maintenance)
1 hour Attainment Unclassifiable/Attainment
30 day average Attainment -
Rolling 3-month average - Unclassified/Attainment
Sulfates 24 hour Attainment -
Hydrogen Sulfide (H2S) 1 hour Unclassified -
Vinyl Chloride 24 hour Attainment -
Notes:

Abbreviations:
µg/m3 - micrograms per cubic meter
CARB - California Air Resources Board
SCAQMD - South Coast Air Quality Management District
USEPA - United States Environmental Protection Agency
Pollutant Averaging Period
Orange County Attainment Status1
Ozone (O3)
Respirable Particulate Matter
(PM10)
4 The area is in nonattainment of the 12.0 µg/m3
PM2.5 standard that was in effect prior to the adoption of the more stringent

9.0 µg/m3 standard on February 7, 2024. CARB submitted initial recommendations for area designations for the 9.0 µg/m3 standard in February 2025, with final area designations expected to be issued by the USEPA in February 2026. Available at:
https://ww2.arb.ca.gov/our-work/programs/state-and-federal-area-designations/federal-area-designations/pm2-5. Accessed:

October 2025.
1 Attainment status for SCAQMD obtained from: https://www.aqmd.gov/docs/default-source/clean-air-plans/air-qualitymanagement-plans/2022-air-quality-management-plan/final-2022-aqmp/05-ch2.pdf. Accessed: October 2025. 2 See California Code of Regulations Title 17 Sections 60200-60210. 3 See 40 Code of Federal Regulations Part 81.

Fine Particulate Matter (PM2.5)
Carbon Monoxide (CO)
Nitrogen Dioxide (NO2)
Lead (Pb)
Sulfur Dioxide (SO2)

Item: 11
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Table 2-3. Air Quality Data for Nearest Monitoring Station Costco Foothill RanchLake Forest, California
DRAFT
Pollutant1
Averaging
Time 2020 2021 2022 2023 2024
Most Stringent Ambient Air
Quality Standard2
1 hour 0.171 ppm 0.105 ppm 0.102 ppm 0.089 ppm 0.104 ppm 0.09 ppm (CAAQS) 8 hours 0.122 ppm 0.081 ppm 0.076 ppm 0.076 ppm 0.079 ppm 0.070 ppm (CAAQS/NAAQS) 24 hours 53 µg/m3 35 µg/m3 90 µg/m3 146 µg/m3 118 µg/m3 50 µg/m3 (CAAQS) Annual 16.8 µg/m3 15.6 µg/m3 22.3 µg/m3 24.0 µg/m3 26.5 µg/m3 20 µg/m3 (CAAQS) 24 hours 35.0 µg/m3 28.7 µg/m3 33.1 µg/m3 33.2 µg/m3 49.7 µg/m3 35 µg/m3 (NAAQS) Annual 8.81 µg/m3 8.27 µg/m3 9.87 µg/m3 9.07 µg/m3 10.31 µg/m3 9 µg/m3 (NAAQS) 1 hour - 0.0059 ppm 0.0061 ppm 0.0232 ppm 0.0082 ppm 75 ppb (NAAQS) 24 hours - - - - - 40 ppb (CAAQS)
1 hour 69.9 ppb 72.3 ppb 62.0 ppb 58.1 ppb 55.8 ppb 100 ppb (NAAQS) Annual 18.8 ppb 18.9 ppb 18.9 ppb 19.6 ppb 19.8 ppb 30 ppb (CAAQS) 1 hour 1.7 ppm 1.0 ppm 2.6 ppm 2.4 ppm 3.3 ppm 20 ppm (CAAQS) 8 hours 0.8 ppm 0.8 ppm 1.9 ppm 1.9 ppm 2.7 ppm 9.0 ppm (CAAQS/NAAQS) Notes:

Abbreviations:μg/m3 - micrograms per cubic meter PM10 - particulate matter less than 10 microns in diameter CAAQS - California Ambient Air Quality Standards PM2.5 - particulate matter less than 2.5 microns in diameter CO - carbon monoxide ppb - parts per billionLA - Los Angeles ppm - parts per million NAAQS - National Ambient Air Quality Standards SCAQMD - South Coast Air Quality Management DistrictNO2 - nitrogen dioxide SO2 - sulfur dioxide 6 The Saddleback Valley Monitoring Station was used for 2020-2021 and the I-5 Near Road Monitoring Station was used for 2022-2024 due to missing data from the Saddleback Valley Monitoring Station at the time of this report preparation.

CO6
Ozone3
PM10
3 PM2.5
3 SO2
4 NO2
5 5 The I-5 Near Road Monitoring Station was used for 2020-2024. 2 Most Stringent Ambient Air Quality Standard obtained from Table 2-1. 4 The South Coast LA County 3 Monitoring Station was used for 2020 and the South Coast LA County 4 Monitoring Station was used for 2021-2024. 1 Data was obtained from SCAQMD's Historical Air Quality Data by Year. Available at: https://www.aqmd.gov/home/air-quality/historical-air-qualitydata/historical-data-by-year. Accessed: September 2025.3 The Saddleback Valley Monitoring Station was used for 2020-2021 and the Central Orange County Monitoring Station was used for 2022-2024 due to missing data from the Saddleback Valley and I-5 Near Road Monitoring Stations at the time of this report preparation.

851
Table 2-4. Frequency of Local Air Quality Standard Violations Costco Foothill RanchLake Forest, California
DRAFT
National
24-Hour PM10
California
24-Hour PM10
National
24-Hour PM2.5
California
1-Hour O3
California
8-Hour O3
National
8-Hour O3
2020 0 1 0 20 32 322021 0002882022 0701112023 0700222024 064333 Notes:

Abbreviations:O3 - ozone
PM10 - particulate matter less than 10 microns in diameterPM2.5 - particulate matter less than 2.5 microns in diameterSCAQMD - South Coast Air Quality Management District Number of Days Exceeding Standard1,2
Year
2 The Saddleback Valley Monitoring Station was used for 2020-2021 and the Central Orange County Monitoring Station was used for 2022-2024 due to missing data from the Saddleback Valley and I-5 Near Road Monitoring Stations at the time of this report preparation. 1 Data was obtained from SCAQMD's Historical Air Quality Data by Year. Available at: https://www.aqmd.gov/home/air-quality/historical-air-qualitydata/historical-data-by-year. Accessed: September 2025.

852
Table 3-1. South Coast Air Quality Management District Air Quality Significance Thresholds
Costco Foothill Ranch
Lake Forest, California
DRAFT
Pollutant Construction Operation
NOX 100 55
VOC 75 55
PM10 150 150
PM2.5 55 55
SOX 150 150
CO 550 550
Lead 3 3
TACs
(including carcinogens and
non-carcinogens)
Odor
GHG
NO2
1-hour average
Annual Arithmetic Mean
PM10
24-hour Average
Annual Average
PM2.5
24-hour Average
SO2
1-hour Average
24-hour Average
CO
1-hour Average
8-hour Average
Source:
µg/m3 - micrograms per cubic meter PM10 - respirable particulate matter CO - carbon monoxide PM2.5 - fine particulate matter
CO2e - carbon dioxide equivalents ppm - parts per million GHG - greenhouse gases SCAQMD - South Coast Air Quality Management District lbs - pounds SO2 - sulfur dioxide
MT - metric ton SOX - sulfur oxides
NO2 - nitrogen dioxide VOC - volatile organic compounds NOx - nitrogen oxides yr - year
SCAQMD is in attainment; project is significant if it causes or contributes to an exceedance of the following attainment standards:

0.18 ppm (state)

0.03 ppm (state) and 0.0534 ppm (federal)

10.4 µg/m3
(construction); 2.5 µg/m3 (operation)

1.0 µg/m3

10.4 µg/m3 (construction); 2.5 µg/m3 (operation)

0.25 ppm (state); 0.075 ppm (federal – 99th percentile)

0.04 ppm (state)
Mass Daily Thresholds1 (lbs/day)
Toxic Air Contaminants (TACs), Odor, and GHG Thresholds1 Maximum Incremental Cancer Risk ≥ 10 in 1 million
Cancer Burden > 0.5 excess cancer cases (in areas ≥ 1 in 1 million) Chronic & Acute Hazard Index ≥ 1.0 (project increment)
Project creates an odor nuisance pursuant to SCAQMD Rule 402 Ambient Air Quality Standards for Criteria Pollutants1
10,000 MT/yr CO2e for industrial facilities
Abbreviations:

SCAQMD is in attainment; project is significant if it causes or contributes to an exceedance of the following attainment standards:
20 ppm (state) and 35 ppm (federal)

9.0 ppm (state/federal)
1 SCAQMD. 2023. South Coast AQMD Air Quality Significance Thresholds. March. Available at:
https://www.aqmd.gov/docs/default-source/ceqa/handbook/south-coast-aqmd-air-quality-significance-thresholds.pdf.

Accessed: July 2025.

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Table 4-1. Construction Schedule - Proposed Project
Costco Foothill RanchLake Forest, California
DRAFT
CalEEMod
®
Phase Typ
e1
Construction
Phase Name1 Start Date1 End Date1
Phase Duration2
(da
y
s)
Demolition Demolition 10/5/2026 11/28/2026 48
Site Preparation Site Preparation 11/29/2026 12/12/2026 12 Grading Grading 12/13/2026 2/27/2027 66
Building Construction 1/23/2027 6/29/2027 135
Concrete Pour 1/23/2027 5/21/2027 102
Paving Paving 5/22/2027 6/11/2027 18
Architectural Coating Architectural Coating 5/17/2027 6/29/2027 38 Notes:

Abbreviations:CalEEMod
® - California Emissions Estimator Model
Building Construction3
3 The Building Construction phases includes a concrete pour subphase which begins on the first day of Building Construction phase and ends the day before the Paving phase begins.
1 Construction phases and duration are based on Project-specific information. 2 The construction work week was assumed to be 6 days per week.

854
Table 4-2. Construction Equipment Assumptions
Costco Foothill RanchLake Forest, California
DRAFT
CalEEMod®
Phase Type
Construction
Phase Name Equipment Type
Number of
Equipment per
day1
Hours per
day1
Horsepower1
(hp) Load Factor1
Concrete/Industrial Saws 1 8 33 0.73Excavators 3 8 36 0.38Rubber Tired Dozers 2 8 367 0.40Rubber Tired Dozers 3 8 367 0.40Tractors/Loaders/Backhoes 4 8 84 0.37Excavators 2 8 36 0.38Graders 1 8 148 0.41Rubber Tired Dozers 1 8 367 0.40Scrapers 2 8 423 0.48Tractors/Loaders/Backhoes 2 8 84 0.37Cranes 1 7 367 0.29Forklifts 3 8 82 0.20Generator Sets 1 8 14 0.74Tractors/Loaders/Backhoes 3 7 84 0.37Welders 1 8 46 0.45Pavers 2 8 81 0.42Paving Equipment 2 8 89 0.36Rollers 2 8 36 0.38 Architectural Coating Architectural Coating Air Compressors 1 6 37 0.48 Notes:

Abbreviations:CalEEMod® - California Emissions Estimator Model hp - horsepower
Demolition Demolition
Site Preparation Site Preparation
Grading Grading
Building Construction
&
Concrete Pour2
Building Construction
Paving Paving
2 The Building Construction phases includes the Concrete Pour subphase. The equipment in the Building Construction phase would be used throughout the duration of the Building Construction phase, including during the Concrete Pour subphase. 1 Number of equipment and operation hours based on CalEEMod® defaults. Available at: www.caleemod.com.

855
Table 4-3. Construction Material Movement
Costco Foothill RanchLake Forest, California
DRAFT
Construction Phase Name
Material Imported1
(yd3)
Material Exported1
(yd3)
Grading 26,795 0
Notes:
1 Soil import and export quantities based on Project-specific data.

Abbreviations:
yd3 - cubic yard

856
Table 4-4. Construction Demolition Assumptions
Costco Foothill Ranch
Lake Forest, California
DRAFT
Construction Phase Name
Material Exported1,2,3
(tons)
Demolition 23,295
Notes:
1 Demolition material based on Project-specific data.

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Table 4-5. Construction Trip Assumptions
Costco Foothill RanchLake Forest, California
DRAFT
CalEEMod®
Phase Type
Construction
Phase Name
Worker Trips
per Day1,2
Vendor Trips
per Day1,2
Hauling Trips
per Day1,3
Concrete Truck Trips
per Day1,4
Demolition Demolition 15 0 121 0
Site Preparation Site Preparation 18 0 0 0
Grading Grading 20 0 51 0
Building Construction
Building Construction
&
Concrete Pour5
53 27 0 8
Paving Paving 15 0 0 0
Architectural Coating Architectural Coating 21 0 0 0
Notes:

Abbreviations:CalEEMod® - California Emissions Estimator Model4 Project construction will include concrete pours during the Building Construction phase. For the purposes of this analysis, these concrete trucks are modeled as heavy-heavy duty vendor truck trips in CalEEMod®. The one-way trip length for the concrete truck trips is assumed to be the CalEEMod® default one-way trip length of 10.20 miles of vendor trips. 1 Trips are presented as one-way trips.2 Worker and vendor trips are based on CalEEMod® defaults. The one-way trip lengths for worker and vendor trips is assumed the CalEEMod® default values of 18.50 and 10.20 miles, respectively.5 The Building Construction phase includes a Concrete Pour subphase. The worker and vendor trips in the Building Construction phase would be used throughout the duration of the Building Construction phase, including during the Concrete Pour subphase. The concrete trucks trips would occur only during the Concrete Pour subphase.
3 Hauling trips reflect CalEEMod® defaults based on Project-specific estimates of material movement shown in Table 4-3 and Table 4-4. The one-way trip length for hauling trips is assumed to be the CalEEMod® default value of 20 miles.

858
Table 4-6. Operational Mobile Sources Activity Data
Costco Foothill RanchLake Forest, California
Tri
p Typ
e1
Average One-Way
Trip Length2
(miles)
Daily Trips3,4,5
(one-wa
y tri
ps/day)
Daily VMT3,6
(mi/day)
Customer and Employee Vehicles -- 13,893 -4,737Delivery Trucks (Warehouse and Tire Center) 37 24 888Notes:Abbreviations:mi - mileVMT - vehicle miles traveled1 The trip type is based on Project-specific information. The fleet mix and emission factors used for each trip type can be found in Appendix C.2 The trip length for delivery trucks is based on Project-specific information. 6 Daily VMT for the delivery trucks estimated as a product of the average trip length and number of daily trips.5 Daily trips for the delivery trucks is based on Project-specific information. The warehouse will receive 10 truck deliveries per day. The tire center will receive deliveries from 2 trucks per week, so it is conservatively assumed that both of these trips could happen on a single day. Each delivery truck would result in two (2) one-way trips. 4 Daily trips for customer and employee vehicles are calculated as the sum of Costco warehouse total trip ends and latent demand trips (primary and diverted). Latent demand trips are trips associated with Costco members making more frequent trips to existing Costco locations due to latent demand. Please see Table 8 and Table 25 of the Foothill Ranch Costco Focused Transportation Impact Study for further details. 3 Trips and VMT for customer and employee vehicles were obtained from the Foothill Ranch Costco Focused Transportation Impact Study (Kittelson & Associates, Inc.).

859
Table 4-7. Operational On-Site Mobile Sources Activity Data Costco Foothill RanchLake Forest, California
DRAFT
Trip Type1
Average On-Site One-Way Trip
Length2,3
(miles)
Daily On-Site Trips4,5
(one-way trips/day)
Daily On-Site VMT6
(mi/day)
Customer and Employee Vehicles 0.15 12,081 1,856Delivery Trucks (Warehouse and Tire Center) 0.37 24 9Notes:

Abbreviations:mi - mileVMT - vehicle miles traveled6 Daily VMT is estimated as a product of the average trip length and number of daily trips.1 The trip type is based on Project-specific information. The fleet mix and emission factors used for each trip type can be found in Appendix C.2 The trip length for customer and employee vehicles represents the average distance that a customer or employee may travel on-site.3 The trip length for delivery trucks is based on the on-site delivery truck loop distance for delivery trucks.4 Trips for customer and employee vehicles were obtained from the Foothill Ranch Costco Focused Transportation Impact Study (Kittelson & Associates, Inc.). Daily trips for customer and employee vehicles were approximated based on the Costco warehouse total trip ends. Please see Table 8 of Foothill Ranch Costco Focused Transportation Impact Study for further details. 5 Daily trips for the delivery trucks is based on Project-specific information. The warehouse will receive 10 truck deliveries per day. The tire center will receive deliveries from 2 trucks per week, so it is conservatively assumed that both of these trips could happen on a single day. Each delivery truck would result in two (2) one-way trips.

860
Table 4-8. Operational Emergency Generator Assumptions
Costco Foothill RanchLake Forest, California
Equipment Type Fuel Type1 Number of Units Per Day1 Hours/Day1 Hours/Year2 Horsepower1 Load Factor3 Emergency Generator CNG 1 1 200 95 0.73
Abbreviations:

CalEEMod® - California Emissions Estimator Model
CNG - compressed natural gasSCAQMD - South Coast Air Quality Management DistrictNotes:
1 Based on Project-specific information. Note, the emission factors used for assessing the emissions can be found in Appendix C.2 Per SCAQMD Rule 1110.2, emergency standby engines must not operate more than 200 hours a year. Available at:
https://www.aqmd.gov/docs/default-source/rule-book/reg-xi/r1110_2.pdf. Accessed: September 2025. 3 Based on CalEEMod® defaults.

861
Table 4-9. Summary of Maximum Daily Criteria Air Pollutant Emissions for Project Construction Costco Foothill Ranch
Lake Forest, California
VOC2 NOx CO SOX
3 PM10 PM2.5
Unmitigated Construction (2026) 3.2 31.6 30.3 0.1 10.0 5.1 Unmitigated Construction (2027) 48.2 40.9 46.1 0.1 3.6 1.9 SCAQMD Mass Daily Significance
Thresholds4 75 100 550 150 150 55
Exceeds Threshold for any
Year of Construction? NO NO NO NO NO NO
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
CO - carbon monoxide
lb - pound
NOx - nitrogen oxide compounds (NO + NO2)
PM10 - particulate matter less than 10 microns in diameter PM2.5 - particulate matter less than 2.5 microns in diameter ROG - reactive organic gases
SCAQMD - South Coast Air Quality Management District
SO2 - sulfur dioxide
SOx - sulfur oxide compounds
VOC - volatile organic compounds
4 SCAQMD Air Quality Significance Thresholds. Available at http://www.aqmd.gov/docs/defaultsource/ceqa/handbook/south-coast-aqmd-air-quality-significance-thresholds.pdf?sfvrsn=25. Accessed: July 2025. 2 For purposes of this analysis VOC emissions are assumed to be equal to ROG. 3 For purposes of this analysis SOX emissions are assumed to be equal to SO2.

Maximum Daily Criteria Air Pollutant Emission Estimates1 Scenario1 (lb/day)
1 Emissions for project construction were estimated using CalEEMod® (see Appendix A-1) and additional concrete truck idling emissions (see Appendix B, Table B-2). Project construction emissions assume watering control consistent with SCAQMD Rule 403.

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Table 4-10. Summary of Maximum Daily Criteria Air Pollutant Emission Estimates for Project Operation
Costco Foothill Ranch
Lake Forest, California
VOC2 NOx CO SOX
3 PM10 PM2.5
Area4 5.2 0.06 7.2 0.00 0.01 0.01
Energy4 0.01 0.27 0.22 0.00 0.02 0.02
Mobile4,5,6,7 33.3 11.8 74.4 0.02 -2.4 -0.5
Stationary Sources4 0.00 0.02 0.14 0.00 0.00 0.00
Total Daily Emissions (lb/day) 38.6 12.1 81.8 0.02 -2.4 -0.5 SCAQMD Mass Daily Significance
Thresholds8 55 55 550 150 150 55
Exceeds Threshold? NO NO NO NO NO NO
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
CO - carbon monoxide
lb - pound
NOx - nitrogen oxide compounds (NO + NO2)
PM10 - particulate matter less than 10 microns in diameter PM2.5 - particulate matter less than 2.5 microns in diameter ROG - reactive organic gases
SCAQMD - South Coast Air Quality Management District
SO2 - sulfur dioxide
SOx - sulfur oxide compounds
TRU - transport refrigeration unit
VMT - vehicle miles traveled
VOC - volatile organic compounds
Maximum Daily Criteria Air Pollutant Emission Estimates1 (lb/day)
1 Emissions totals may not add up due to rounding. Emissions shown as zero may be non-zero values; however, they are below a meaningful reporting level for this analysis.

Emission Category
8 SCAQMD Air Quality Significance Thresholds. Available at http://www.aqmd.gov/docs/defaultsource/ceqa/handbook/south-coast-aqmd-air-quality-significance-thresholds.pdf?sfvrsn=25. Accessed: October 2025. 2 For purposes of this analysis VOC emissions are assumed to be equal to ROG. 4 Total emissions were estimated using CalEEMod® (see Appendix A-1). 6 TRU emissions obtained from Table C-3 in Appendix C.
3 For purposes of this analysis SOX emissions are assumed to be equal to SO2. 5 Delivery truck emissions were estimated using CalEEMod® (see Appendix A-2). 7 Negative mobile PM10 and PM2.5 emissions are attributed to the negative VMT for customer and employee vehicles, obtained from the Foothill Ranch Costco Focused Transportation Impact Study (Kittelson & Associates, Inc.). See Table 4-6.

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Table 6-1. Comparison of On-site Project Emissions to SCAQMD Localized Significance Thresholds
Costco Foothill Ranch
Lake Forest, California
CO NOX 1-hour NOX
1 PM10 PM2.5
Project Construction2 40.5 35.2 35.2 8.9 5.1
SCAQMD LSTs3 1804.0 197.0 109.4 12.0 8.0
SCAQMD LSTs at high end of
interpolation 1804.0 197.0 109.4 12.0 8.0
Exceeds SCAQMD LSTs? NO NO NO NO NO
Project Operation4 83.4 8.9 8.9 1.4 0.4
SCAQMD LSTs3 1804.0 197.0 109.4 3.0 2.0
Exceeds SCAQMD LSTs? NO NO NO NO NO
Notes:

Abbreviations:

ArcGIS - Arc Geographic Information System
CO - carbon monoxide
hr - hour
lb - pounds
LST - localized significance threshold
NO2 - nitrogen dioxide
NOX - nitrogen oxides
PM10 - particulate matter less than 10 microns in aerodynamic diameter PM2.5 - particulate matter less than 2.5 microns in aerodynamic diameter ppm - parts per million
SCAQMD - South Coast Air Quality Management District
Operation of Proposed Project
1 An approximated LST was estimated to evaluate the federal 1-hour NO2 standard, as the SCAQMD LST has not been updated to reflect this standard. This value was estimated by scaling the SCAQMD LST that represents the state 1-hr NO2 standard with the ratio of the federal to state 1-hr NO2 standard (0.10 ppm/0.18 ppm).
3 LSTs based on the receptor located at less than 25 meters from a 16.3-acre project site in SRA 19 (Saddleback Valley). Distance was measured using ArcGIS. LSTs were obtained from the 2008 SCAQMD Final Localized Significance Threshold Methodology, Appendix C, Mass Rate LST Look-up Tables. Available at:
http://www.aqmd.gov/home/regulations/ceqa/air-quality-analysis-handbook/localized-significance-thresholds.

Accessed: September 2025.
4 On-site emissions from operation of the proposed Project include emissions from area sources and energy sources (obtained from Appendix A-1), and mobile sources (Appendix A-3 and Appendix A-4). 2 On-site emissions from construction of the proposed Project obtained from Appendix A-1 and Appendix B, Table B-2.

Construction of Proposed Project
Scenario
Maximum Daily On-site Emissions
(lb/day)

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DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll

APPENDIX A
CalEEMod RUNS
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DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll
APPENDIX A-1
CalEEMod RUN FOR PROJECT CONSTRUCTION AND OPERATION
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Costco Foothill Ranch (Project) 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

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, Unmitigated

3. Construction Emissions Details

3.1. Demolition (2026) - Unmitigated

3.3. Site Preparation (2026) - Unmitigated

3.5. Grading (2026) - Unmitigated

3.7. Grading (2027) - Unmitigated

3.9. Building Construction (2027) - Unmitigated
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3.11. Concrete Pour (2027) - Unmitigated

3.13. Paving (2027) - Unmitigated

3.15. Architectural Coating (2027) - Unmitigated

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated

4.2.3. Natural Gas Emissions By Land Use - Unmitigated

4.3. Area Emissions by Source

4.3.1. Unmitigated

4.4. Water Emissions by Land Use

4.4.1. Unmitigated

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated

4.7. Offroad Emissions By Equipment Type
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4.7.1. Unmitigated

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated

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

5. Activity Data

5.1. Construction Schedule

5.2. Off-Road Equipment

5.2.1. Unmitigated

5.3. Construction Vehicles

5.3.1. Unmitigated

5.4. Vehicles

5.4.1. Construction Vehicle Control Strategies

5.5. Architectural Coatings
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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

5.10. Operational Area Sources

5.10.1. Hearths

5.10.2. Architectural Coatings

5.10.3. Landscape Equipment

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated

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5.14.1. Unmitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

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 Costco Foothill Ranch (Project)
Construction Start Date 10/5/2026
Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 4.2
Location 26602 Towne Centre Dr, Foothill Ranch, CA 92610, USA County Orange
City Lake Forest
Air District South Coast AQMD
Air Basin South Coast
TAZ 6046
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.32

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
Discount Club 165 1000sqft 3.8 165,070 62,553 — — —
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Parking Lot 12 Acre 12 0.00 0.00 — — —

1.3. User-Selected Emission Reduction Measures by Emissions Sector No measures selected

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. 49 48 18 29 0.05 0.66 1.4 2.1 0.61 0.34 0.94 — 6,013 6,013 0.22 0.22 5.6 6,081 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 5.4 4.3 41 46 0.12 1.4 9.1 10 1.3 4.0 5.1 — 14,416 14,416 0.77 1.4 0.45 14,678 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 5.8 5.6 8.5 11 0.02 0.29 1.7 1.9 0.27 0.43 0.63 — 3,038 3,038 0.14 0.21 1.2 3,090 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 1.1 1.0 1.5 1.9 < 0.005 0.05 0.30 0.34 0.05 0.08 0.12 — 503 503 0.02 0.03 0.20 512

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 Daily -
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Item: 11
873
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 8 / 43
2027 49 48 18 29 0.05 0.66 1.4 2.1 0.61 0.34 0.94 — 6,013 6,013 0.22 0.22 5.6 6,081 Daily -
Winter
(Max)
— — — — — — — — — — — — — — — — — —
2026 4.0 3.2 32 30 0.09 1.2 9.1 10 1.1 4.0 5.1 — 11,930 11,930 0.77 1.4 0.45 12,352 2027 5.4 4.3 41 46 0.12 1.4 5.8 7.2 1.3 2.0 3.3 — 14,416 14,416 0.71 0.82 0.31 14,678 Average
Daily
— — — — — — — — — — — — — — — — — —
2026 0.78 0.57 6.5 5.5 0.02 0.22 1.7 1.9 0.20 0.43 0.63 — 2,211 2,211 0.13 0.21 1.2 2,277 2027 5.8 5.6 8.5 11 0.02 0.29 1.0 1.3 0.27 0.34 0.61 — 3,038 3,038 0.14 0.16 1.2 3,090 Annual — — — — — — — — — — — — — — — — — —
2026 0.14 0.10 1.2 1.0 < 0.005 0.04 0.30 0.34 0.04 0.08 0.12 — 366 366 0.02 0.03 0.19 377 2027 1.1 1.0 1.5 1.9 < 0.005 0.05 0.19 0.25 0.05 0.06 0.11 — 503 503 0.02 0.03 0.20 512

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. 39 38 7.2 67 -0.01 0.08 -3.3 -3.3 0.07 -0.85 -0.78 406 888 1,294 43 0.86 -10 2,606 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 38 37 7.7 74 -0.01 0.06 -3.3 -3.3 0.06 -0.85 -0.79 406 1,022 1,428 43 0.90 0.51 2,768 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 38 37 7.6 76 -0.01 0.07 -3.3 -3.3 0.07 -0.85 -0.78 406 976 1,382 43 0.89 -4.0 2,711 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 7.0 6.8 1.4 14 > -0.005 0.01 -0.61 -0.60 0.01 -0.15 -0.14 67 162 229 7.1 0.15 -0.65 449 Item: 11
874
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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 34 33 6.8 60 -0.01 0.04 -3.3 -3.3 0.04 -0.85 -0.81 — -1,217 -1,217 1.6 0.78 -11 -955 Area 5.3 5.2 0.06 7.2 < 0.005 0.01 — 0.01 0.01 — 0.01 — 30 30 < 0.005 < 0.005 — 30 Energy 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 1,955 1,955 0.22 0.02 — 1,967 Water — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Waste — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Refrig. — — — — — — — — — — — — — — — — 0.79 0.79
Stationa
ry
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Vegetati
on
— — — — — — — — — — — — -1.0 -1.0 — — — -1.0
Total 39 38 7.2 67 -0.01 0.08 -3.3 -3.3 0.07 -0.85 -0.78 406 888 1,294 43 0.86 -10 2,606 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 34 33 7.4 74 -0.01 0.04 -3.3 -3.3 0.04 -0.85 -0.81 — -1,053 -1,053 1.8 0.82 -0.29 -763 Area 4.0 4.0 — — — — — — — — — — — — — — — —
Energy 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 1,955 1,955 0.22 0.02 — 1,967 Water — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Waste — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Refrig. — — — — — — — — — — — — — — — — 0.79 0.79
Stationa
ry
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Vegetati
on
— — — — — — — — — — — — -1.0 -1.0 — — — -1.0
Total 38 37 7.7 74 -0.01 0.06 -3.3 -3.3 0.06 -0.85 -0.79 406 1,022 1,428 43 0.90 0.51 2,768 Item: 11
875
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 10 / 43
Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 33 33 7.3 71 -0.01 0.04 -3.3 -3.3 0.04 -0.85 -0.81 — -1,096 -1,096 1.8 0.81 -4.7 -815 Area 4.9 4.8 0.04 4.9 < 0.005 0.01 — 0.01 0.01 — 0.01 — 20 20 < 0.005 < 0.005 — 20 Energy 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 1,955 1,955 0.22 0.02 — 1,967 Water — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Waste — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Refrig. — — — — — — — — — — — — — — — — 0.79 0.79
Stationa
ry
< 0.005 < 0.005 0.01 0.08 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 29 29 0.06 < 0.005 0.00 31 Vegetati
on
— — — — — — — — — — — — -1.0 -1.0 — — — -1.0
Total 38 37 7.6 76 -0.01 0.07 -3.3 -3.3 0.07 -0.85 -0.78 406 976 1,382 43 0.89 -4.0 2,711 Annual — — — — — — — — — — — — — — — — — —
Mobile 6.1 5.9 1.3 13 > -0.005 0.01 -0.61 -0.60 0.01 -0.15 -0.15 — -181 -181 0.29 0.13 -0.79 -135 Area 0.90 0.88 0.01 0.90 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.3 3.3 < 0.005 < 0.005 — 3.4 Energy 0.01 < 0.005 0.05 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 324 324 0.04 < 0.005 — 326 Water — — — — — — — — — — — 3.9 11 15 0.40 0.01 — 28
Waste — — — — — — — — — — — 63 0.00 63 6.3 0.00 — 222
Refrig. — — — — — — — — — — — — — — — — 0.13 0.13
Stationa
ry
< 0.005 < 0.005 < 0.005 0.01 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 4.8 4.8 0.01 < 0.005 0.00 5.1 Vegetati
on
— — — — — — — — — — — — -0.17 -0.17 — — — -0.17
Total 7.0 6.8 1.4 14 > -0.005 0.01 -0.61 -0.60 0.01 -0.15 -0.14 67 162 229 7.1 0.15 -0.65 449

3. Construction Emissions Details

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) Item: 11
876
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 11 / 43
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

2.7 2.3 21 19 0.03 0.84 — 0.84 0.78 — 0.78 — 3,427 3,427 0.14 0.03 — 3,438 Demoliti
on
— — — — — — 6.7 6.7 — 1.0 1.0 — — — — — — —
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

0.36 0.30 2.7 2.5 < 0.005 0.11 — 0.11 0.10 — 0.10 — 451 451 0.02 < 0.005 — 452 Demoliti
on
— — — — — — 0.88 0.88 — 0.13 0.13 — — — — — — —
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

0.07 0.05 0.50 0.46 < 0.005 0.02 — 0.02 0.02 — 0.02 — 75 75 < 0.005 < 0.005 — 75 Demoliti
on
— — — — — — 0.16 0.16 — 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 Offsite — — — — — — — — — — — — — — — — — —
Item: 11
877
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Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.05 0.05 0.05 0.68 0.00 0.00 0.20 0.20 0.00 0.05 0.05 — 186 186 < 0.005 0.01 0.02 188 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 0.81 0.12 10 4.4 0.06 0.11 2.2 2.3 0.11 0.62 0.72 — 8,318 8,318 0.63 1.3 0.44 8,726 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 0.01 0.09 0.00 0.00 0.03 0.03 0.00 0.01 0.01 — 25 25 < 0.005 < 0.005 0.04 25 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 0.11 0.02 1.4 0.58 0.01 0.01 0.29 0.30 0.01 0.08 0.09 — 1,094 1,094 0.08 0.17 0.95 1,148 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.02 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 4.1 4.1 < 0.005 < 0.005 0.01 4.2 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 0.25 0.11 < 0.005 < 0.005 0.05 0.06 < 0.005 0.01 0.02 — 181 181 0.01 0.03 0.16 190

3.3. Site Preparation (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)
— — — — — — — — — — — — — — — — — —
Item: 11
878
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 13 / 43
Off-Roa 3.7 3.1 29 29 0.05 1.2 — 1.2 1.1 — 1.1 — 5,298 5,298 0.21 0.04 — 5,316 d
Equipm
ent
Dust
From
Material
Movement
— — — — — — 7.7 7.7 — 3.9 3.9 — — — — — — —
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

0.12 0.10 0.96 0.95 < 0.005 0.04 — 0.04 0.04 — 0.04 — 174 174 0.01 < 0.005 — 175 Dust
From
Material
Movement
— — — — — — 0.25 0.25 — 0.13 0.13 — — — — — — —
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

0.02 0.02 0.17 0.17 < 0.005 0.01 — 0.01 0.01 — 0.01 — 29 29 < 0.005 < 0.005 — 29 Dust
From
Material
Movement
— — — — — — 0.05 0.05 — 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 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Item: 11
879
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Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.06 0.06 0.06 0.80 0.00 0.00 0.23 0.23 0.00 0.05 0.05 — 217 217 < 0.005 0.01 0.02 219 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 0.00 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
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.03 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 7.2 7.2 < 0.005 < 0.005 0.01 7.3 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 0.00 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 — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.2 1.2 < 0.005 < 0.005 < 0.005 1.2 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 0.00 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

3.5. Grading (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

3.6 3.0 27 28 0.06 1.1 — 1.1 1.0 — 1.0 — 6,599 6,599 0.27 0.05 — 6,621 Item: 11
880
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 15 / 43
Dust — — — — — — 3.6 3.6 — 1.4 1.4 — — — — — — —
From
Material
Movement
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

0.16 0.14 1.2 1.2 < 0.005 0.05 — 0.05 0.05 — 0.05 — 294 294 0.01 < 0.005 — 295 Dust
From
Material
Movement
— — — — — — 0.16 0.16 — 0.06 0.06 — — — — — — —
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

0.03 0.02 0.22 0.22 < 0.005 0.01 — 0.01 0.01 — 0.01 — 49 49 < 0.005 < 0.005 — 49 Dust
From
Material
Movement
— — — — — — 0.03 0.03 — 0.01 0.01 — — — — — — —
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 0.07 0.07 0.07 0.91 0.00 0.00 0.26 0.26 0.00 0.06 0.06 — 248 248 < 0.005 0.01 0.02 251 Item: 11
881
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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 0.96 0.04 0.26 0.30 — 3,480 3,480 0.26 0.55 0.18 3,650 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.04 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 11 11 < 0.005 < 0.005 0.02 11 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 0.19 0.08 < 0.005 < 0.005 0.04 0.04 < 0.005 0.01 0.01 — 155 155 0.01 0.02 0.14 163 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.9 1.9 < 0.005 < 0.005 < 0.005 1.9 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 — 26 26 < 0.005 < 0.005 0.02 27

3.7. Grading (2027) - 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

3.5 2.9 26 27 0.06 1.0 — 1.0 0.96 — 0.96 — 6,598 6,598 0.27 0.05 — 6,621 Dust
From
Material
Movement
— — — — — — 3.6 3.6 — 1.4 1.4 — — — — — — —
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 Item: 11
882
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Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.48 0.40 3.5 3.7 0.01 0.14 — 0.14 0.13 — 0.13 — 899 899 0.04 0.01 — 902 Dust
From
Material
Movement
— — — — — — 0.49 0.49 — 0.19 0.19 — — — — — — —
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

0.09 0.07 0.64 0.68 < 0.005 0.03 — 0.03 0.02 — 0.02 — 149 149 0.01 < 0.005 — 149 Dust
From
Material
Movement
— — — — — — 0.09 0.09 — 0.04 0.04 — — — — — — —
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 0.07 0.06 0.06 0.85 0.00 0.00 0.26 0.26 0.00 0.06 0.06 — 244 244 < 0.005 0.01 0.02 247 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 0.31 0.05 4.2 1.8 0.02 0.04 0.92 0.96 0.04 0.26 0.30 — 3,412 3,412 0.26 0.55 0.17 3,583 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 0.01 0.12 0.00 0.00 0.04 0.04 0.00 0.01 0.01 — 34 34 < 0.005 < 0.005 0.05 34 Item: 11
883
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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 0.04 0.01 0.57 0.25 < 0.005 0.01 0.12 0.13 0.01 0.04 0.04 — 465 465 0.04 0.07 0.38 488 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.02 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 5.6 5.6 < 0.005 < 0.005 0.01 5.6 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 0.01 < 0.005 0.10 0.04 < 0.005 < 0.005 0.02 0.02 < 0.005 0.01 0.01 — 77 77 0.01 0.01 0.06 81

3.9. Building Construction (2027) - 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)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

1.2 1.0 9.4 13 0.02 0.34 — 0.34 0.31 — 0.31 — 2,397 2,397 0.10 0.02 — 2,405 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 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

1.2 1.0 9.4 13 0.02 0.34 — 0.34 0.31 — 0.31 — 2,397 2,397 0.10 0.02 — 2,405 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
— — — — — — — — — — — — — — — — — —
Item: 11
884
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 19 / 43
Off-Roa 0.46 0.38 3.5 4.8 0.01 0.12 — 0.12 0.11 — 0.11 — 887 887 0.04 0.01 — 890 d
Equipm
ent
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

0.08 0.07 0.63 0.87 < 0.005 0.02 — 0.02 0.02 — 0.02 — 147 147 0.01 < 0.005 — 147 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)
— — — — — — — — — — — — — — — — — —
Worker 0.18 0.15 0.16 2.6 0.00 0.00 0.69 0.69 0.00 0.16 0.16 — 676 676 0.01 0.03 2.1 686 Vendor 0.07 0.02 0.83 0.41 0.01 0.01 0.23 0.24 0.01 0.06 0.07 — 833 833 0.04 0.11 2.0 870 Hauling 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 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.18 0.15 0.16 2.2 0.00 0.00 0.69 0.69 0.00 0.16 0.16 — 644 644 0.01 0.03 0.06 651 Vendor 0.07 0.02 0.87 0.42 0.01 0.01 0.23 0.24 0.01 0.06 0.07 — 833 833 0.04 0.11 0.05 868 Hauling 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
— — — — — — — — — — — — — — — — — —
Worker 0.06 0.06 0.07 0.87 0.00 0.00 0.25 0.25 0.00 0.06 0.06 — 241 241 < 0.005 0.01 0.34 244 Vendor 0.02 0.01 0.32 0.15 < 0.005 < 0.005 0.09 0.09 < 0.005 0.02 0.03 — 308 308 0.02 0.04 0.32 321 Hauling 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 — — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 0.01 0.16 0.00 0.00 0.05 0.05 0.00 0.01 0.01 — 40 40 < 0.005 < 0.005 0.06 40 Item: 11
885
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Vendor < 0.005 < 0.005 0.06 0.03 < 0.005 < 0.005 0.02 0.02 < 0.005 < 0.005 < 0.005 — 51 51 < 0.005 0.01 0.05 53 Hauling 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

3.11. Concrete Pour (2027) - 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)
— — — — — — — — — — — — — — — — — —
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 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
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
— — — — — — — — — — — — — — — — — —
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 — — — — — — — — — — — — — — — — — —
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)
— — — — — — — — — — — — — — — — — —
Worker 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 Vendor 0.03 0.01 0.39 0.19 < 0.005 < 0.005 0.08 0.08 < 0.005 0.02 0.02 — 288 288 0.02 0.05 0.54 303 Hauling 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 Item: 11
886
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Worker 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 Vendor 0.03 0.01 0.40 0.19 < 0.005 < 0.005 0.08 0.08 < 0.005 0.02 0.02 — 288 288 0.02 0.05 0.01 303 Hauling 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
— — — — — — — — — — — — — — — — — —
Worker 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 Vendor 0.01 < 0.005 0.11 0.05 < 0.005 < 0.005 0.02 0.02 < 0.005 0.01 0.01 — 81 81 0.01 0.01 0.06 85 Hauling 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 — — — — — — — — — — — — — — — — — —
Worker 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 Vendor < 0.005 < 0.005 0.02 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 13 13 < 0.005 < 0.005 0.01 14 Hauling 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

3.13. Paving (2027) - 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)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.88 0.74 6.9 10.0 0.01 0.30 — 0.30 0.27 — 0.27 — 1,511 1,511 0.06 0.01 — 1,516 Paving 1.8 1.8 — — — — — — — — — — — — — — — —
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 Item: 11
887
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.04 0.04 0.34 0.49 < 0.005 0.01 — 0.01 0.01 — 0.01 — 75 75 < 0.005 < 0.005 — 75 Paving 0.09 0.09 — — — — — — — — — — — — — — — —
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

0.01 0.01 0.06 0.09 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 12 12 < 0.005 < 0.005 — 12 Paving 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 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.05 0.04 0.04 0.74 0.00 0.00 0.20 0.20 0.00 0.05 0.05 — 192 192 < 0.005 0.01 0.61 195 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 0.00 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 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
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 — 9.1 9.1 < 0.005 < 0.005 0.01 9.3 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 Item: 11
888
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Hauling 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 — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.5 1.5 < 0.005 < 0.005 < 0.005 1.5 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 0.00 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

3.15. Architectural Coating (2027) - 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)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.14 0.11 0.83 1.1 < 0.005 0.02 — 0.02 0.02 — 0.02 — 134 134 0.01 < 0.005 — 134 Architect
ural
Coating
s
44 44 — — — — — — — — — — — — — — — —
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 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.01 0.01 0.09 0.12 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 14 14 < 0.005 < 0.005 — 14 Item: 11
889
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Architect 4.6 4.6 — — — — — — — — — — — — — — — —
ural
Coating
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 0.02 0.02 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 2.3 2.3 < 0.005 < 0.005 — 2.3 Architect
ural
Coating
s

0.84 0.84 — — — — — — — — — — — — — — — —
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)
— — — — — — — — — — — — — — — — — —
Worker 0.07 0.06 0.06 1.0 0.00 0.00 0.28 0.28 0.00 0.06 0.06 — 271 271 < 0.005 0.01 0.86 274 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 0.00 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 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 0.01 0.10 0.00 0.00 0.03 0.03 0.00 0.01 0.01 — 27 27 < 0.005 < 0.005 0.04 28 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 0.00 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 — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.02 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 4.5 4.5 < 0.005 < 0.005 0.01 4.6 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 Item: 11
890
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Hauling 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

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Mobile source emissions results are presented in Sections 2.6. No further detailed breakdown of emissions is available.

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — 1,266 1,266 0.15 0.02 — 1,275
Parking
Lot
— — — — — — — — — — — — 372 372 0.04 0.01 — 375
Total — — — — — — — — — — — — 1,638 1,638 0.19 0.02 — 1,650 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — 1,266 1,266 0.15 0.02 — 1,275
Parking
Lot
— — — — — — — — — — — — 372 372 0.04 0.01 — 375
Total — — — — — — — — — — — — 1,638 1,638 0.19 0.02 — 1,650 Annual — — — — — — — — — — — — — — — — — —
Item: 11
891
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Discount — — — — — — — — — — — — 210 210 0.02 < 0.005 — 211 Club
Parking
Lot
— — — — — — — — — — — — 62 62 0.01 < 0.005 — 62
Total — — — — — — — — — — — — 271 271 0.03 < 0.005 — 273

4.2.3. Natural Gas Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club

0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 Parking
Lot

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 Total 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club

0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 Parking
Lot

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 Total 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 Annual — — — — — — — — — — — — — — — — — —
Discount
Club

0.01 < 0.005 0.05 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 52 52 < 0.005 < 0.005 — 53 Parking
Lot

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 Total 0.01 < 0.005 0.05 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 52 52 < 0.005 < 0.005 — 53 Item: 11
892
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 27 / 43

4.3. Area Emissions by Source

4.3.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Source TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

3.6 3.6 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.46 0.46 — — — — — — — — — — — — — — — —
Landsca
pe
Equipm
ent

1.3 1.2 0.06 7.2 < 0.005 0.01 — 0.01 0.01 — 0.01 — 30 30 < 0.005 < 0.005 — 30 Total 5.3 5.2 0.06 7.2 < 0.005 0.01 — 0.01 0.01 — 0.01 — 30 30 < 0.005 < 0.005 — 30 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

3.6 3.6 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.46 0.46 — — — — — — — — — — — — — — — —
Total 4.0 4.0 — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Item: 11
893
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 28 / 43
Consum 0.65 0.65 — — — — — — — — — — — — — — — —
er
Product
Architect
ural
Coating
s

0.08 0.08 — — — — — — — — — — — — — — — —
Landsca
pe
Equipm
ent

0.16 0.15 0.01 0.90 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.3 3.3 < 0.005 < 0.005 — 3.4 Total 0.90 0.88 0.01 0.90 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.3 3.3 < 0.005 < 0.005 — 3.4

4.4. Water Emissions by Land Use

4.4.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Item: 11
894
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Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 3.9 11 15 0.40 0.01 — 28
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 3.9 11 15 0.40 0.01 — 28

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 63 0.00 63 6.3 0.00 — 222
Item: 11
895
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 30 / 43
Parking — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Lot
Total — — — — — — — — — — — 63 0.00 63 6.3 0.00 — 222

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — — — — — 0.79 0.79
Total — — — — — — — — — — — — — — — — 0.79 0.79
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — — — — — 0.79 0.79
Total — — — — — — — — — — — — — — — — 0.79 0.79
Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — — — — — 0.13 0.13
Total — — — — — — — — — — — — — — — — 0.13 0.13

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Item: 11
896
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 31 / 43
Equipm TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e ent
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Emerge
ncy
Generat
or
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Total < 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Emerge
ncy
Generat
or
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Item: 11
897
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Total < 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Annual — — — — — — — — — — — — — — — — — —
Emerge
ncy
Generat
or
< 0.005 < 0.005 < 0.005 0.01 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 4.8 4.8 0.01 < 0.005 0.00 5.1 Total < 0.005 < 0.005 < 0.005 0.01 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 4.8 4.8 0.01 < 0.005 0.00 5.1

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10. Soil Carbon Accumulation By Vegetation Type

4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Vegetati
on
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Item: 11
898
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 33 / 43
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Other — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Other — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Annual — — — — — — — — — — — — — — — — — —
Other — — — — — — — — — — — — -0.11 -0.11 — — — -0.11
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.11 -0.11 — — — -0.11

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Grassla
nd
— — — — — — — — — — — — -0.38 -0.38 — — — -0.38
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.38 -0.38 — — — -0.38
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Item: 11
899
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 34 / 43
Grassla — — — — — — — — — — — — -0.38 -0.38 — — — -0.38 nd
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.38 -0.38 — — — -0.38
Annual — — — — — — — — — — — — — — — — — —
Grassla
nd
— — — — — — — — — — — — -0.06 -0.06 — — — -0.06
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.06 -0.06 — — — -0.06

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Species TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Item: 11
900
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 35 / 43
Sequest — — — — — — — — — — — — — — — — — —
ered
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —

5. Activity Data

5.1. Construction Schedule
Phase Name Phase Type Start Date End Date Days Per Week Work Days per Phase Phase Description Demolition Demolition 10/5/2026 11/28/2026 6.0 48 —
Site Preparation Site Preparation 11/29/2026 12/12/2026 6.0 12 — Grading Grading 12/13/2026 2/27/2027 6.0 66 —
Building Construction Building Construction 1/23/2027 6/29/2027 6.0 135 — Concrete Pour Building Construction 1/23/2027 5/21/2027 6.0 102 — Paving Paving 5/22/2027 6/11/2027 6.0 18 —
Architectural Coating Architectural Coating 5/17/2027 6/29/2027 6.0 38 — Item: 11
901
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5.2. Off-Road Equipment

5.2.1. Unmitigated
Phase Name Equipment Type Fuel Type Engine Tier Number per Day Hours Per Day Horsepower Load Factor Demolition Concrete/Industrial
Saws
Diesel Average 1.00 8.0 33 0.73
Demolition Excavators Diesel Average 3.0 8.0 36 0.38
Demolition Rubber Tired Dozers Diesel Average 2.0 8.0 367 0.40 Site Preparation Rubber Tired Dozers Diesel Average 3.0 8.0 367 0.40 Site Preparation Tractors/Loaders/Back
hoes
Diesel Average 4.0 8.0 84 0.37
Grading Excavators Diesel Average 2.0 8.0 36 0.38
Grading Graders Diesel Average 1.00 8.0 148 0.41
Grading Rubber Tired Dozers Diesel Average 1.00 8.0 367 0.40 Grading Scrapers Diesel Average 2.0 8.0 423 0.48
Grading Tractors/Loaders/Back
hoes
Diesel Average 2.0 8.0 84 0.37
Building Construction Cranes Diesel Average 1.00 7.0 367 0.29 Building Construction Forklifts Diesel Average 3.0 8.0 82 0.20 Building Construction Generator Sets Diesel Average 1.00 8.0 14 0.74 Building Construction Tractors/Loaders/Back
hoes
Diesel Average 3.0 7.0 84 0.37
Building Construction Welders Diesel Average 1.00 8.0 46 0.45 Paving Pavers Diesel Average 2.0 8.0 81 0.42
Paving Paving Equipment Diesel Average 2.0 8.0 89 0.36
Paving Rollers Diesel Average 2.0 8.0 36 0.38
Architectural Coating Air Compressors Diesel Average 1.00 6.0 37 0.48

5.3. Construction Vehicles
Item: 11
902
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 37 / 43

5.3.1. Unmitigated
Phase Name Trip Type One-Way Trips per Day Miles per Trip Vehicle Mix Demolition Worker 15 19 LDA,LDT1,LDT2
Demolition Vendor — 10 HHDT,MHDT
Demolition Hauling 121 20 HHDT
Demolition Onsite truck — — HHDT
Site Preparation Worker 18 19 LDA,LDT1,LDT2
Site Preparation Vendor — 10 HHDT,MHDT
Site Preparation Hauling 0.00 20 HHDT
Site Preparation Onsite truck — — HHDT
Grading Worker 20 19 LDA,LDT1,LDT2
Grading Vendor — 10 HHDT,MHDT
Grading Hauling 51 20 HHDT
Grading Onsite truck — — HHDT
Building Construction Worker 53 19 LDA,LDT1,LDT2
Building Construction Vendor 27 10 HHDT,MHDT
Building Construction Hauling 0.00 20 HHDT
Building Construction Onsite truck — — HHDT
Concrete Pour Worker 0.00 19 LDA,LDT1,LDT2
Concrete Pour Vendor 8.2 10 HHDT
Concrete Pour Hauling 0.00 20 HHDT
Concrete Pour Onsite truck — — HHDT
Paving Worker 15 19 LDA,LDT1,LDT2
Paving Vendor — 10 HHDT,MHDT
Paving Hauling 0.00 20 HHDT
Paving Onsite truck — — HHDT
Architectural Coating Worker 21 19 LDA,LDT1,LDT2
Architectural Coating Vendor — 10 HHDT,MHDT
Item: 11
903
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Architectural Coating Hauling 0.00 20 HHDT
Architectural Coating Onsite truck — — HHDT

5.4. Vehicles

5.4.1. Construction Vehicle Control Strategies
Non-applicable. No control strategies activated by user.

5.5. Architectural Coatings
Phase Name Residential Interior Area
Coated (sq ft)
Residential Exterior Area
Coated (sq ft)
Non-Residential Interior Area
Coated (sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
Architectural Coating 0.00 0.00 247,605 82,535 32,644

5.6. Dust Mitigation

5.6.1. Construction Earthmoving Activities
Phase Name Material Imported (cy) Material Exported (cy) Acres Graded (acres) Material Demolished (Ton of Debris)
Acres Paved (acres)
Demolition 0.00 0.00 0.00 23,295 0.00
Site Preparation — — 18 0.00 0.00
Grading 26,795 0.00 237 0.00 0.00
Paving 0.00 0.00 0.00 0.00 12

5.6.2. Construction Earthmoving Control Strategies
Control Strategies Applied Frequency (per day) PM10 Reduction PM2.5 Reduction Water Exposed Area 2 61% 61%
Water Demolished Area 2 36% 36%

5.7. Construction Paving
Item: 11
904
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Phase Name Land Use Area Paved (acres) % Asphalt
Paving Discount Club 0.00 0%
Paving Parking Lot 12 100%

5.8. Construction Electricity Consumption and Emissions Factors kWh per Year and Emission Factor (lb/MWh)
Year kWh per Year CO2 CH4 N2O
2026 0.00 297 0.03 < 0.005
2027 0.00 285 0.03 < 0.005

5.9. Operational Mobile Sources

5.9.1. Unmitigated
Land Use Type Trips/Weekday Trips/Saturday Trips/Sunday Trips/Year VMT/Weekday VMT/Saturday VMT/Sunday VMT/Year Total all Land Uses 13,893 13,893 13,893 5,070,945 -4,737 -4,737 -4,737 -1,729,005

5.10. Operational Area Sources

5.10.1. Hearths
Land Use Hearth Type Unmitigated (number) Mitigated (number) Discount Club Wood Fireplaces 0 0
Discount Club Gas Fireplaces 0 0
Discount Club Propane Fireplaces 0 0
Discount Club Electric Fireplaces 0 0
Discount Club No Fireplaces 0 0
Discount Club Conventional Wood Stoves 0 0
Discount Club Catalytic Wood Stoves 0 0
Discount Club Non-Catalytic Wood Stoves 0 0
Item: 11
905
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 40 / 43
Discount Club Pellet Wood Stoves 0 0
Parking Lot Wood Fireplaces 0 0
Parking Lot Gas Fireplaces 0 0
Parking Lot Propane Fireplaces 0 0
Parking Lot Electric Fireplaces 0 0
Parking Lot No Fireplaces 0 0
Parking Lot Conventional Wood Stoves 0 0
Parking Lot Catalytic Wood Stoves 0 0
Parking Lot Non-Catalytic Wood Stoves 0 0
Parking Lot Pellet Wood Stoves 0 0

5.10.2. Architectural Coatings
— Residential Interior Area
Coated (sq ft)
Residential Exterior Area
Coated (sq ft)
Non-Residential Interior Area
Coated (sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
undefined 0.00 0.00 247,605 82,535 32,644

5.10.3. Landscape Equipment
Season Unit Value
Snow Days day/yr 0.00
Summer Days day/yr 250

5.11. Operational Energy Consumption

5.11.1. Unmitigated
Electricity (kWh/yr) and CO2 and CH4 and N2O and Natural Gas (kBTU/yr) Land Use Electricity (kWh/yr) CO2 CH4 N2O Natural Gas (kBTU/yr) Discount Club 1,621,213 285 0.0330 0.0040 988,265
Parking Lot 476,600 285 0.0330 0.0040 0.00
Item: 11
906
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 41 / 43

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated
Land Use Indoor Water (gal/year) Outdoor Water (gal/year) Discount Club 12,227,151 810,710
Parking Lot 0.00 0.00

5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Discount Club 710 0.00
Parking Lot 0.00 0.00

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
Land Use Equipment Type Refrigerant GWP Quantity (kg) Operations Leak Rate Service Leak Rate Times Serviced Discount Club Other commercial A/C
and heat pumps
R-410A 2,088 < 0.005 4.0 4.0 18
Discount Club Stand-alone retail
refrigerators and
freezers
R-134a 1,430 0.04 1.00 0.00 1.00

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources
Item: 11
907
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 42 / 43

5.16.1. Emergency Generators and Fire Pumps
Equipment Type Fuel Type Number per Day Hours per Day Hours per Year Horsepower Load Factor Emergency Generator CNG 1.00 1.00 200 95 0.73

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated
Vegetation Land Use Type Vegetation Soil Type Initial Acres Final Acres Other Alfisols 1.3 1.4
Urban Other 15 15

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated
Biomass Cover Type Initial Acres Final Acres
Grassland 1.3 1.4
Urban 15 15

5.18.2. Sequestration

5.18.2.1. Unmitigated
Tree Type Number Electricity Saved (kWh/year) Natural Gas Saved (btu/year) Item: 11
908
Costco Foothill Ranch (Project) Custom Report, 11/14/2025 43 / 43

8. User Changes to Default Data

8.1. Justifications
Screen Justification
Characteristics: Utility Information CO2 emission factor estimated based upon RPS compliance.

Land Use Based on project-specific information.

Construction: Construction Phases Based on project-specific information.

Construction: Off-Road Equipment Concrete pour phase only includes concrete trucks.

Construction: Dust From Material Movement Construction material movement based on project-specific information. Watering 2x/day based on SCAQMD Rule 403, Table 1.

Construction: Trips and VMT Based on project-specific information.

Construction: Electricity CO2 emission factor estimated based upon RPS compliance.

Operations: Fleet Mix Based on project-specific information.

Operations: Generators + Pumps EF Based on project-specific information.

Item: 11
909
DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll
APPENDIX A-2
CalEEMod RUN FOR DELIVERY TRUCKS
Item: 11
910
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 1 / 19
Costco Foothill Ranch (Delivery Trucks) 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

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, Unmitigated

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated

4.2.3. Natural Gas Emissions By Land Use - Unmitigated

4.3. Area Emissions by Source

4.3.1. Unmitigated
Item: 11
911
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 2 / 19

4.4. Water Emissions by Land Use

4.4.1. Unmitigated

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated

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

5. Activity Data

5.9. Operational Mobile Sources
Item: 11
912
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 3 / 19

5.9.1. Unmitigated

5.10. Operational Area Sources

5.10.1. Hearths

5.10.2. Architectural Coatings

5.10.3. Landscape Equipment

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers
Item: 11
913
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 4 / 19

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

8. User Changes to Default Data

8.1. Justifications
Item: 11
914
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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name Costco Foothill Ranch (Delivery Trucks)
Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 4.2
Location 26602 Towne Centre Dr, Foothill Ranch, CA 92610, USA County Orange
City Lake Forest
Air District South Coast AQMD
Air Basin South Coast
TAZ 6046
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.32

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
Discount Club 165 1000sqft 3.8 165,070 62,553 — — —
Parking Lot 12 Acre 12 0.00 0.00 — — —
Item: 11
915
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1.3. User-Selected Emission Reduction Measures by Emissions Sector No measures selected

2. Emissions Summary

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. 0.05 0.04 3.4 0.37 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,052 3,052 < 0.005 0.48 5.7 3,201 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.05 0.04 3.6 0.38 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,053 3,053 < 0.005 0.48 0.15 3,196 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.04 0.04 3.1 0.32 0.02 0.04 0.69 0.73 0.04 0.19 0.23 0.00 2,616 2,616 < 0.005 0.41 2.1 2,741 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.01 0.01 0.56 0.06 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 0.00 433 433 < 0.005 0.07 0.35 454

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 0.05 0.04 3.4 0.37 0.03 0.05 0.81 0.86 0.05 0.22 0.26 — 3,052 3,052 < 0.005 0.48 5.7 3,201 Item: 11
916
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Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.05 0.04 3.4 0.37 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,052 3,052 < 0.005 0.48 5.7 3,201 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 0.05 0.04 3.6 0.38 0.03 0.05 0.81 0.86 0.05 0.22 0.26 — 3,053 3,053 < 0.005 0.48 0.15 3,196 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.05 0.04 3.6 0.38 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,053 3,053 < 0.005 0.48 0.15 3,196 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 0.04 0.04 3.1 0.32 0.02 0.04 0.69 0.73 0.04 0.19 0.23 — 2,616 2,616 < 0.005 0.41 2.1 2,741 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.04 0.04 3.1 0.32 0.02 0.04 0.69 0.73 0.04 0.19 0.23 0.00 2,616 2,616 < 0.005 0.41 2.1 2,741 Annual — — — — — — — — — — — — — — — — — —
Mobile 0.01 0.01 0.56 0.06 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 — 433 433 < 0.005 0.07 0.35 454 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.01 0.01 0.56 0.06 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 0.00 433 433 < 0.005 0.07 0.35 454

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Mobile source emissions results are presented in Sections 2.6. No further detailed breakdown of emissions is available.

4.2. Energy
Item: 11
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4.2.1. Electricity Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.2.3. Natural Gas Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.3. Area Emissions by Source
Item: 11
918
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4.3.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Source TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Item: 11
919
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 10 / 19
Total 0.00 0.00 — — — — — — — — — — — — — — — —

4.4. Water Emissions by Land Use

4.4.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Item: 11
920
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 11 / 19
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
921
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4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
922
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 13 / 19
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10. Soil Carbon Accumulation By Vegetation Type

4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Vegetati
on
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
923
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Species TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Item: 11
924
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 15 / 19
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —

5. Activity Data
Item: 11
925
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 16 / 19

5.9. Operational Mobile Sources

5.9.1. Unmitigated
Land Use Type Trips/Weekday Trips/Saturday Trips/Sunday Trips/Year VMT/Weekday VMT/Saturday VMT/Sunday VMT/Year Total all Land Uses 24 24 24 7,509 888 888 888 277,817

5.10. Operational Area Sources

5.10.1. Hearths
Land Use Hearth Type Unmitigated (number) Mitigated (number) Discount Club Wood Fireplaces 0 0
Discount Club Gas Fireplaces 0 0
Discount Club Propane Fireplaces 0 0
Discount Club Electric Fireplaces 0 0
Discount Club No Fireplaces 0 0
Discount Club Conventional Wood Stoves 0 0
Discount Club Catalytic Wood Stoves 0 0
Discount Club Non-Catalytic Wood Stoves 0 0
Discount Club Pellet Wood Stoves 0 0
Parking Lot Wood Fireplaces 0 0
Parking Lot Gas Fireplaces 0 0
Parking Lot Propane Fireplaces 0 0
Parking Lot Electric Fireplaces 0 0
Parking Lot No Fireplaces 0 0
Parking Lot Conventional Wood Stoves 0 0
Parking Lot Catalytic Wood Stoves 0 0
Parking Lot Non-Catalytic Wood Stoves 0 0
Parking Lot Pellet Wood Stoves 0 0
Item: 11
926
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 17 / 19

5.10.2. Architectural Coatings
— Residential Interior Area
Coated (sq ft)
Residential Exterior Area
Coated (sq ft)
Non-Residential Interior Area
Coated (sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
undefined 0.00 0.00 247,605 82,535 32,644

5.10.3. Landscape Equipment
Season Unit Value
Snow Days day/yr 0.00
Summer Days day/yr 0.00

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Discount Club 0.00 0.00
Parking Lot 0.00 0.00

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
Item: 11
927
Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 18 / 19

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated
Vegetation Land Use Type Vegetation Soil Type Initial Acres Final Acres

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated
Biomass Cover Type Initial Acres Final Acres

5.18.2. Sequestration

5.18.2.1. Unmitigated
Tree Type Number Electricity Saved (kWh/year) Natural Gas Saved (btu/year)

8. User Changes to Default Data
Item: 11
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Costco Foothill Ranch (Delivery Trucks) Custom Report, 11/14/2025 19 / 19

8.1. Justifications
Screen Justification
Characteristics: Utility Information CO2 emission factor estimated based upon RPS compliance.

Land Use Based on project-specific information.

Operations: Fleet Mix Updated for delivery truck mobile emissions only.

Operations: Vehicle EF Emission factors for Diesel HHDTs were obtained from the default EMFAC2021 output for Orange County - South Coast calendar year 2027. HFC emission factors were kept as CalEEMod defaults.

Operations: Consumer Products Updated for delivery truck mobile emissions only.

Operations: Architectural Coatings Updated for delivery truck mobile emissions only.

Operations: Landscape Equipment Updated for delivery truck mobile emissions only.

Operations: Energy Use Updated for delivery truck mobile emissions only.

Operations: Water and Waste Water Updated for delivery truck mobile emissions only.

Operations: Solid Waste Updated for delivery truck mobile emissions only.

Operations: Refrigerants Updated for delivery truck mobile emissions only.

Item: 11
929
DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll
APPENDIX A-3
CalEEMod RUN FOR ON-SITE MOBILE SOURCES
(EMPLOYEE AND CUSTOMER VEHICLES)
Item: 11
930
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 1 / 19
On-Site Mobile Sources (Employee and Customer Vehicles) 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

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, Unmitigated

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated

4.2.3. Natural Gas Emissions By Land Use - Unmitigated

4.3. Area Emissions by Source
Item: 11
931
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 2 / 19

4.3.1. Unmitigated

4.4. Water Emissions by Land Use

4.4.1. Unmitigated

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated

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

5. Activity Data
Item: 11
932
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 3 / 19

5.9. Operational Mobile Sources

5.9.1. Unmitigated

5.10. Operational Area Sources

5.10.1. Hearths

5.10.2. Architectural Coatings

5.10.3. Landscape Equipment

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps
Item: 11
933
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 4 / 19

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

8. User Changes to Default Data

8.1. Justifications
Item: 11
934
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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name On-Site Mobile Sources (Employee and Customer Vehicles) Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 4.2
Location 26602 Towne Centre Dr, Foothill Ranch, CA 92610, USA County Orange
City Lake Forest
Air District South Coast AQMD
Air Basin South Coast
TAZ 6046
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.32

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
Discount Club 165 1000sqft 3.8 165,070 62,553 — — —
Parking Lot 12 Acre 12 0.00 0.00 — — —
Item: 11
935
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1.3. User-Selected Emission Reduction Measures by Emissions Sector No measures selected

2. Emissions Summary

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. 30 29 6.8 65 0.03 0.06 1.3 1.4 0.05 0.33 0.38 0.00 3,194 3,194 1.5 0.78 4.3 3,469 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 30 29 7.4 76 0.03 0.06 1.3 1.4 0.05 0.33 0.38 0.00 3,162 3,162 1.6 0.83 0.11 3,450 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 29 29 7.3 74 0.03 0.06 1.3 1.4 0.05 0.33 0.38 0.00 3,172 3,172 1.6 0.81 1.9 3,457 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 5.4 5.2 1.3 13 0.01 0.01 0.24 0.25 0.01 0.06 0.07 0.00 525 525 0.27 0.13 0.31 572

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 30 29 6.8 65 0.03 0.06 1.3 1.4 0.05 0.33 0.38 — 3,194 3,194 1.5 0.78 4.3 3,469 Item: 11
936
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Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 30 29 6.8 65 0.03 0.06 1.3 1.4 0.05 0.33 0.38 0.00 3,194 3,194 1.5 0.78 4.3 3,469 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 30 29 7.4 76 0.03 0.06 1.3 1.4 0.05 0.33 0.38 — 3,162 3,162 1.6 0.83 0.11 3,450 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 30 29 7.4 76 0.03 0.06 1.3 1.4 0.05 0.33 0.38 0.00 3,162 3,162 1.6 0.83 0.11 3,450 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 29 29 7.3 74 0.03 0.06 1.3 1.4 0.05 0.33 0.38 — 3,172 3,172 1.6 0.81 1.9 3,457 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 29 29 7.3 74 0.03 0.06 1.3 1.4 0.05 0.33 0.38 0.00 3,172 3,172 1.6 0.81 1.9 3,457 Annual — — — — — — — — — — — — — — — — — —
Mobile 5.4 5.2 1.3 13 0.01 0.01 0.24 0.25 0.01 0.06 0.07 — 525 525 0.27 0.13 0.31 572 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 5.4 5.2 1.3 13 0.01 0.01 0.24 0.25 0.01 0.06 0.07 0.00 525 525 0.27 0.13 0.31 572

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Mobile source emissions results are presented in Sections 2.6. No further detailed breakdown of emissions is available.

4.2. Energy
Item: 11
937
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4.2.1. Electricity Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.2.3. Natural Gas Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.3. Area Emissions by Source
Item: 11
938
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 9 / 19

4.3.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Source TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Item: 11
939
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 10 / 19
Total 0.00 0.00 — — — — — — — — — — — — — — — —

4.4. Water Emissions by Land Use

4.4.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Item: 11
940
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 11 / 19
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
941
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4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
942
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Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10. Soil Carbon Accumulation By Vegetation Type

4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Vegetati
on
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
943
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Species TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Item: 11
944
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 15 / 19
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —

5. Activity Data
Item: 11
945
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 16 / 19

5.9. Operational Mobile Sources

5.9.1. Unmitigated
Land Use Type Trips/Weekday Trips/Saturday Trips/Sunday Trips/Year VMT/Weekday VMT/Saturday VMT/Sunday VMT/Year Total all Land Uses 12,081 12,081 12,081 4,409,565 1,856 1,856 1,856 677,440

5.10. Operational Area Sources

5.10.1. Hearths
Land Use Hearth Type Unmitigated (number) Mitigated (number) Discount Club Wood Fireplaces 0 0
Discount Club Gas Fireplaces 0 0
Discount Club Propane Fireplaces 0 0
Discount Club Electric Fireplaces 0 0
Discount Club No Fireplaces 0 0
Discount Club Conventional Wood Stoves 0 0
Discount Club Catalytic Wood Stoves 0 0
Discount Club Non-Catalytic Wood Stoves 0 0
Discount Club Pellet Wood Stoves 0 0
Parking Lot Wood Fireplaces 0 0
Parking Lot Gas Fireplaces 0 0
Parking Lot Propane Fireplaces 0 0
Parking Lot Electric Fireplaces 0 0
Parking Lot No Fireplaces 0 0
Parking Lot Conventional Wood Stoves 0 0
Parking Lot Catalytic Wood Stoves 0 0
Parking Lot Non-Catalytic Wood Stoves 0 0
Parking Lot Pellet Wood Stoves 0 0
Item: 11
946
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 17 / 19

5.10.2. Architectural Coatings
— Residential Interior Area
Coated (sq ft)
Residential Exterior Area
Coated (sq ft)
Non-Residential Interior Area
Coated (sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
undefined 0.00 0.00 247,605 82,535 32,644

5.10.3. Landscape Equipment
Season Unit Value
Snow Days day/yr 0.00
Summer Days day/yr 0.00

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Discount Club 0.00 0.00
Parking Lot 0.00 0.00

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
Item: 11
947
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 18 / 19

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated
Vegetation Land Use Type Vegetation Soil Type Initial Acres Final Acres

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated
Biomass Cover Type Initial Acres Final Acres

5.18.2. Sequestration

5.18.2.1. Unmitigated
Tree Type Number Electricity Saved (kWh/year) Natural Gas Saved (btu/year)

8. User Changes to Default Data
Item: 11
948
On-Site Mobile Sources (Employee and Customer Vehicles) Custom Report, 11/14/2025 19 / 19

8.1. Justifications
Screen Justification
Characteristics: Utility Information CO2 emission factor estimated based upon RPS compliance.

Land Use Based on project-specific information.

Operations: Fleet Mix Based on project-specific information.

Operations: Consumer Products Updated for on-site project mobile emissions only.

Operations: Architectural Coatings Updated for on-site project mobile emissions only.

Operations: Landscape Equipment Updated for on-site project mobile emissions only.

Operations: Energy Use Updated for on-site project mobile emissions only.

Operations: Water and Waste Water Updated for on-site project mobile emissions only.

Operations: Solid Waste Updated for on-site project mobile emissions only.

Operations: Refrigerants Updated for on-site project mobile emissions only.

Item: 11
949
DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll
APPENDIX A-4
CalEEMod RUN FOR ON-SITE MOBILE SOURCES
(DELIVERY TRUCKS)
Item: 11
950
On-Site Mobile Sources (Delivery Trucks) Custom Report, 11/14/2025 1 / 19
On-Site Mobile Sources (Delivery Trucks) 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

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, Unmitigated

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated

4.2.3. Natural Gas Emissions By Land Use - Unmitigated

4.3. Area Emissions by Source

4.3.1. Unmitigated
Item: 11
951
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4.4. Water Emissions by Land Use

4.4.1. Unmitigated

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated

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

5. Activity Data

5.9. Operational Mobile Sources
Item: 11
952
On-Site Mobile Sources (Delivery Trucks) Custom Report, 11/14/2025 3 / 19

5.9.1. Unmitigated

5.10. Operational Area Sources

5.10.1. Hearths

5.10.2. Architectural Coatings

5.10.3. Landscape Equipment

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers
Item: 11
953
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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. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

8. User Changes to Default Data

8.1. Justifications
Item: 11
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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name On-Site Mobile Sources (Delivery Trucks)
Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 4.2
Location 26602 Towne Centre Dr, Foothill Ranch, CA 92610, USA County Orange
City Lake Forest
Air District South Coast AQMD
Air Basin South Coast
TAZ 6046
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.32

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
Discount Club 165 1000sqft 3.8 165,070 62,553 — — —
Parking Lot 12 Acre 12 0.00 0.00 — — —
Item: 11
955
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1.3. User-Selected Emission Reduction Measures by Emissions Sector No measures selected

2. Emissions Summary

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. 0.02 0.02 0.37 0.25 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 0.00 68 68 < 0.005 0.01 0.06 72 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.02 0.02 0.40 0.25 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 0.00 70 70 < 0.005 0.01 < 0.005 73 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.02 0.01 0.33 0.21 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 0.00 59 59 < 0.005 0.01 0.02 61 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. < 0.005 < 0.005 0.06 0.04 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 0.00 9.7 9.7 < 0.005 < 0.005 < 0.005 10

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 0.02 0.02 0.37 0.25 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 — 68 68 < 0.005 0.01 0.06 72 Item: 11
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Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.02 0.02 0.37 0.25 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 0.00 68 68 < 0.005 0.01 0.06 72 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 0.02 0.02 0.40 0.25 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 — 70 70 < 0.005 0.01 < 0.005 73 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.02 0.02 0.40 0.25 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 0.00 70 70 < 0.005 0.01 < 0.005 73 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 0.02 0.01 0.33 0.21 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 — 59 59 < 0.005 0.01 0.02 61 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.02 0.01 0.33 0.21 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 0.00 59 59 < 0.005 0.01 0.02 61 Annual — — — — — — — — — — — — — — — — — —
Mobile < 0.005 < 0.005 0.06 0.04 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 9.7 9.7 < 0.005 < 0.005 < 0.005 10 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total < 0.005 < 0.005 0.06 0.04 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 0.00 9.7 9.7 < 0.005 < 0.005 < 0.005 10

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Mobile source emissions results are presented in Sections 2.6. No further detailed breakdown of emissions is available.

4.2. Energy
Item: 11
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4.2.1. Electricity Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.2.3. Natural Gas Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.3. Area Emissions by Source
Item: 11
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4.3.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Source TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Consum
er
Product
s

0.00 0.00 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.00 0.00 — — — — — — — — — — — — — — — —
Item: 11
959
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Total 0.00 0.00 — — — — — — — — — — — — — — — —

4.4. Water Emissions by Land Use

4.4.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Item: 11
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Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
961
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4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
962
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Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10. Soil Carbon Accumulation By Vegetation Type

4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Vegetati
on
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Item: 11
963
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Species TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Item: 11
964
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Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —

5. Activity Data
Item: 11
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5.9. Operational Mobile Sources

5.9.1. Unmitigated
Land Use Type Trips/Weekday Trips/Saturday Trips/Sunday Trips/Year VMT/Weekday VMT/Saturday VMT/Sunday VMT/Year Total all Land Uses 24 24 24 7,509 9.0 9.0 9.0 2,761

5.10. Operational Area Sources

5.10.1. Hearths
Land Use Hearth Type Unmitigated (number) Mitigated (number) Discount Club Wood Fireplaces 0 0
Discount Club Gas Fireplaces 0 0
Discount Club Propane Fireplaces 0 0
Discount Club Electric Fireplaces 0 0
Discount Club No Fireplaces 0 0
Discount Club Conventional Wood Stoves 0 0
Discount Club Catalytic Wood Stoves 0 0
Discount Club Non-Catalytic Wood Stoves 0 0
Discount Club Pellet Wood Stoves 0 0
Parking Lot Wood Fireplaces 0 0
Parking Lot Gas Fireplaces 0 0
Parking Lot Propane Fireplaces 0 0
Parking Lot Electric Fireplaces 0 0
Parking Lot No Fireplaces 0 0
Parking Lot Conventional Wood Stoves 0 0
Parking Lot Catalytic Wood Stoves 0 0
Parking Lot Non-Catalytic Wood Stoves 0 0
Parking Lot Pellet Wood Stoves 0 0
Item: 11
966
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5.10.2. Architectural Coatings
— Residential Interior Area
Coated (sq ft)
Residential Exterior Area
Coated (sq ft)
Non-Residential Interior Area
Coated (sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
undefined 0.00 0.00 247,605 82,535 32,644

5.10.3. Landscape Equipment
Season Unit Value
Snow Days day/yr 0.00
Summer Days day/yr 0.00

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Discount Club 0.00 0.00
Parking Lot 0.00 0.00

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
Item: 11
967
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5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated
Vegetation Land Use Type Vegetation Soil Type Initial Acres Final Acres

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated
Biomass Cover Type Initial Acres Final Acres

5.18.2. Sequestration

5.18.2.1. Unmitigated
Tree Type Number Electricity Saved (kWh/year) Natural Gas Saved (btu/year)

8. User Changes to Default Data
Item: 11
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8.1. Justifications
Screen Justification
Characteristics: Utility Information CO2 emission factor estimated based upon RPS compliance.

Land Use Based on project-specific information.

Operations: Fleet Mix Updated for delivery truck mobile emissions only.

Operations: Vehicle EF Emission factors for Diesel HHDTs were obtained from the default EMFAC2021 output for Orange County - South Coast calendar year 2027. HFC emission factors were kept as CalEEMod defaults.

Operations: Consumer Products Updated for on-site delivery truck mobile emissions only.

Operations: Architectural Coatings Updated for on-site delivery truck mobile emissions only.

Operations: Landscape Equipment Updated for on-site delivery truck mobile emissions only.

Operations: Energy Use Updated for on-site delivery truck mobile emissions only.

Operations: Water and Waste Water Updated for on-site delivery truck mobile emissions only.

Operations: Solid Waste Updated for on-site delivery truck mobile emissions only.

Operations: Refrigerants Updated for on-site delivery truck mobile emissions only.

Item: 11
969
Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
DRAFT
Ramboll

APPENDIX B

EMISSION CALCULATIONS FOR PROJECT CONSTRUCTION
Item: 11
970
DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll
List of Tables
Table B-1:

Table B-2:

Criteria Air Pollutant Emission Factors for Concrete Truck Idling Maximum Daily Criteria Air Pollutant Emissions from Concrete Trucks Idling and On-Road Travel During Project Construction
Item: 11
971
Table B-1. Criteria Air Pollutant Emission Factors for Concrete Truck Idling Costco Foothill RanchLake Forest, California
EMFAC
Vehicle Class Fuel Typ
e
Concrete Truck
Fleet Mix 1
VOC Emission Factor 2,3
(grams/idle-minute)
NOX Emission Factor 2
(grams/idle-minute)
CO Emission Factor 2
(grams/idle-minute)
SOX Emission Factor 2
(grams/idle-minute)
PM10 Emission Factor 2
(grams/idle-minute)
PM2.5 Emission Factor 2
(grams/idle-minute)
HHDT Diesel 100% 0.039 0.46 0.58 8.4E-04 2.5E-04 2.3E-04 Weighted Idling Emission Factor 4 0.039 0.46 0.58 8.4E-04 2.5E-04 2.3E-04 Notes:

Abbreviations:CO - carbon monoxideEMFAC - EMission FACtors modelHHDT - Heavy Heavy-Duty TruckNOx - nitrogen oxide compounds PM10 - particulate matter less than 10 microns in diameter PM2.5 - particulate matter less than 2.5 microns in diameterROG - reactive organic gasesSC - South CoastSOx - sulfur oxide compounds VOC - volatile organic compounds
1 Concrete trucks are conservatively assumed to be diesel-fueled HHDT.2 Idling emission factors were obtained from the default EMFAC2021 project-level output for Orange (SC) sub-area in calendar year 2027. 3 For purposes of this analysis VOC is assumed to be equal to ROG.4 Weighted average emission factors for concrete trucks are calculated as the sumproduct of the project specific fleet mix and the emission factors for the individual vehicle class/fuel categories within that fleet mix.

972
Table B-2. Maximum Daily Criteria Air Pollutant Emissions from Concrete Trucks Idling and On-Road Travel During Project Construction Costco Foothill RanchLake Forest, California
Concrete Truck
Activity
Number of Days
of Concrete Truck
Activity 1
(days)
Daily Trips 1
(round trips/day)
Idle Duration 1
(minutes/ round trip)
VOC
Emissions 2
(lbs/day)
NOX
Emissions
(lbs/day)
CO
Emissions
(lbs/day)
SOX
Emissions
(lbs/day)
PM10
Emissions
(lbs/day)
PM2.5
Emissions
(lbs/day)
Idling 3 102 4 60 0.02 0.25 0.31 0.0005 0.0001 0.0001
On-Road Travel 4 102 4 - 0.01 0.40 0.19 0.002 0.08 0.02

0.03 0.7 0.5 0.002 0.08 0.03
Abbreviations:

CalEEMod - CALifornia Emissions Estimator MODelCO - carbon monoxideNOx - nitrogen oxide compounds PM2.5 - particulate matter less than 2.5 microns in diameter PM10 - particulate matter less than 10 microns in diameter ROG - reactive organic gasesSOx - sulfur oxide compounds VOC - volatile organic compounds
4 Obtained from the CalEEMod model run for construction in Appendix A-1.

Total Emissions
Notes:
1 Based on Project-specific information.2 For purposes of this analysis VOC is assumed to be equal to ROG.3 Idling emissions were estimated as a product of the emission factors from Table B-1, the idle duration per round trip, and the number of round trips per day.

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DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll

APPENDIX C

EMISSION CALCULATIONS FOR PROJECT OPERATION
Item: 11
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DRAFT Foothill Ranch Costco Project
Air Quality Technical Report
Lake Forest, California
Ramboll
List of Tables
Table C-1:

Table C-2:

Table C-3:

Table C-4:

Table C-5:

Operational Mobile Source Fleet Mixes
Operational Delivery Truck Criteria Air Pollutant Emission Factors Operational Mobile Source CAP Emission Factors for Transport Refrigeration Units
Maximum Daily Criteria Air Pollutant Emission Estimates for Transport Refrigeration Units
Operational Emergency Generator Criteria Air Pollutant Emission Factors Item: 11
975
Table C-1. Operational Mobile Source Fleet Mixes
Costco Foothill Ranch
Lake Forest, California
Gasoline 41,402,174 43.67% --
Plug-in Hybrid 1,693,689 1.79% --
Electricity 4,089,427 4.31% --
Diesel 72,324 0.08% --
Gasoline 3,351,769 3.98% --
Plug-in Hybrid 17,553 0.02% --
Electricity 21,261 0.03% --
Diesel 181 0.00% --
Gasoline 22,020,145 23.13% --
Plug-in Hybrid 311,544 0.33% --
Electricity 224,425 0.24% --
Diesel 88,904 0.09% --
Gasoline 12,751,503 13.98% --
Plug-in Hybrid 186,464 0.20% --
Electricity 237,228 0.26% --
Diesel 174,319 0.19% --
Gasoline 1,647,637 1.69% --
Diesel 995,052 1.02% --
Electricity 91,019 0.09% --
Gasoline 244,223 0.26% --
Diesel 433,595 0.46% --
Electricity 22,491 0.02% --
Gasoline 343,883 0.35% --
Diesel 1,162,783 1.17% --
Electricity 35,495 0.04% --
Natural Gas 13,849 0.01% --
Gasoline -- -- --
Diesel 1,309,094 -- 100%
Electricity -- -- --
Natural Gas -- -- --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
MCY Gasoline 2.2% 2.2% 334,154 2.24% --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
Gasoline 54,533 0.24% --
Diesel 29,338 0.13% --
Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel MDV - medium-duty vehicle EMFAC - EMission FACtors model MH - motor homes
HHDT - Heavy heavy-duty truck MHDT - medium heavy-duty trucks LDA - light duty automobiles OBUS - other buses
LDT - light-duty trucks SBUS - school buses
LHDT - light heavy-duty trucks UBUS - urban buses
MCY - motorcycles VMT - vehicle miles traveled
5 The EMFAC vehicle class that represents delivery trucks is HHDT.

MH 0.4% 0.4%
Notes:
1 CalEEMod® default for Orange County, calendar year 2027. 2 Estimated using the CalEEMod® default fleet mix for Orange County. EMFAC vehicle classes that represent vehicles visiting the warehouse include LDA, LDT1, LDT2, MDV, LHDT1, LHDT2, MHDT, MCY, and MH. 3 Default EMFAC2021 output for the Orange County subarea in calendar year 2027. 4 The Project-specific fleet mix for customer and employee vehicles is estimated by apportioning the fleet mix for vehicles visiting the warehouse into the Project-specific fuel types (gasoline, plug-in hybrid, electricity, diesel) within each EMFAC vehicle class for vehicles visiting the warehouse (LDA, LDT1, LDT2, MDV, LHDT1, LHDT2, MHDT, MCY, and MH) using the default EMFAC VMT output for those fuel types.

Delivery Truck
Fleet Mix5
UBUS 0.04% --
SBUS 0.1% --
HHDT 0.6% --
OBUS 0.1% --
LHDT2 0.7% 0.7%
MHDT 1.6% 1.6%
MDV 14.5% 14.6%
LHDT1 2.8% 2.8%
LDT1 4.0% 4.0%
LDT2 23.6% 23.8%

EMFAC VMT
Output3
(miles/day)
Customer and
Employee Vehicles4
LDA 49.5% 49.8%
Vehicle
Category Fuel Type
CalEEMod®
Default Fleet
Mix1
Fleet Mix for
Vehicles
Visiting the
Warehouse2

Item: 11
976
Table C-2. Operational Delivery Truck Criteria Air Pollutant Emission Factors Costco Foothill RanchLake Forest, California
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
DIURN
(g/trip)

HOTSOAK
(g/trip)

RUNLOSS
(g/trip)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
DIURN
(g/trip)

HOTSOAK
(g/trip)

RUNLOSS
(g/trip)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
Annual 1.45E-02 3.66E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.27E-02 3.21E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.66E+00 3.75E+00 2.90E+00 Summer 1.45E-02 3.87E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.27E-02 3.40E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.57E+00 3.58E+00 2.90E+00 Winter 1.45E-02 3.36E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.27E-02 2.96E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.63E+00 3.98E+00 2.90E+00 EMFAC
Vehicle
Class
Fuel
Type Season
NOX Emission Factors1
HHDT Diesel
ROG Emission Factors1 TOG Emission Factors1

977
Table C-2. Operational Delivery Truck Criteria Air Pollutant Emission Factors Costco Foothill RanchLake Forest, California
Annual
Summer
Winter
EMFAC
Vehicle
Class
Fuel
Type Season
HHDT Diesel
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
PMTW
(g/mi)
PMBW
(g/mi)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
PMTW
(g/mi)
PMBW
(g/mi)

6.62E-02 4.69E+00 0.00E+00 1.46E-02 6.87E-03 0.00E+00 2.40E-02 1.91E-03 0.00E+00 8.69E-03 2.69E-02 2.51E-02 2.00E-03 0.00E+00 3.48E-02 7.69E-02

6.62E-02 4.62E+00 0.00E+00 1.46E-02 6.79E-03 0.00E+00 2.40E-02 1.67E-03 0.00E+00 8.69E-03 2.69E-02 2.51E-02 1.75E-03 0.00E+00 3.48E-02 7.69E-02

6.62E-02 4.78E+00 0.00E+00 1.46E-02 6.98E-03 0.00E+00 2.40E-02 2.25E-03 0.00E+00 8.69E-03 2.69E-02 2.51E-02 2.35E-03 0.00E+00 3.48E-02 7.69E-02 Notes:

Abbreviations:CO - carbon monoxideDIURN - diurnal evaporativeEMFAC - EMission FACtors modelg - gramHHDT - Heavy Heavy-Duty TruckHOTSOAK - hot soakIDLEX - idle exhaustmi - mileNOx - nitrogen oxide compounds (NO + NO2) PM10 - particulate matter less than 10 microns in diameter PM2.5 - particulate matter less than 2.5 microns in diameter PMBW - particulate matter from brake wearPMTW - particulate matter from tire wearROG - reactive organic gasesRUNEX - running exhaustRUNLOSS - running lossSOX - sulfur organic gases STREX - starting exhaustTOG - total organic gases
CO Emission Factors1 SOX Emission Factors1 PM2.5 Emission Factors1 PM10 Emission Factors1 1 Emission factors for Diesel HHDTs were obtained from the default EMFAC2021 output for Orange County - South Coast calendar year 2027.

978
Table C-3. Operational Mobile Source CAP Emission Factors for Transport Refrigeration Units Costco Foothill RanchLake Forest, California
Trans
port Refri
geration Unit (TRU) Cate
gor
y 1 Fuel Typ
e
Total Statewide Activity 2
(hr/
year)
VOC Emission Factor 2,3
(lbs/hr)
NOX Emission Factor 2
(lbs/hr)
CO Emission Factor 2
(lbs/hr)
SOX Emission Factor 2
(lbs/hr)
PM10 Emission Factor 2
(lbs/hr)
PM2.5 Emission Factor 2
(lbs/hr)
Transport Refrigeration Unit - Instate Trailer Diesel 2,055,583 1.16E-02 6.75E-02 1.06E-02 1.51E-04 1.49E-03 1.37E-03 Transport Refrigeration Unit - Out-Of-State Trailer Diesel 1,186,175 1.16E-02 8.06E-02 1.07E-02 1.45E-04 2.05E-03 1.89E-03

1.16E-02 7.23E-02 1.06E-02 1.48E-04 1.70E-03 1.56E-03
Notes:

Abbreviations:CAP - criteria air pollutantCO - carbon monoxidehr - hourlbs - poundsNOx - nitrogen oxide compounds PM10 - particulate matter less than 10 microns in diameter PM2.5 - particulate matter less than 2.5 microns in diameter ROG - reactive organic gasesSC - South CoastSOx - sulfur oxide compounds VOC - volatile organic compounds
Weighted Average Emission Factor 4
2 Total statewide activity and exhaust emission factors for TRUs were obtained from OFFROAD2021 emissions output for Orange (SC) sub-area calendar year 2027. 3 For purposes of this analysis VOC is assumed to be equal to ROG.4 The activity weighted average emission factors for TRUs servicing the proposed Project were calculated using the OFFROAD2021 emission factors and total activity for each individual TRU category.1 According to Section 3b. Equipment Types of the 2025 Transportation Refrigeration Unit Emissions Inventory, most of the 2024 base data inventory comprises of out-of-state trailers at 58%, followed by in-State trailers at 20%. Available at:
https://ww2.arb.ca.gov/sites/default/files/2025-05/2025TRUInventory.pdf. Accessed: August 2025.

979
Table C-4. Maximum Daily Criteria Air Pollutant Emission Estimates for Transport Refrigeration Units Costco Foothill RanchLake Forest, California
Mobile Source Activity
Daily TRU Operational Duration 1
(min/day)
VOC Emissions 2
(lbs/day)
NOx Emissions 2
(lbs/day)
CO Emissions 2
(lbs/day)
SOX Emissions 2
(lbs/day)
PM10 Emissions 2
(lbs/day)
PM2.5 Emissions 2
(lbs/day)
TRUs for Warehouse Delivery Trucks 681 0.13 0.82 0.12 0.00 0.02 0.02Notes:

TRU Trip Information:On-Site Operational Time During Truck Idling 15 minutes/round trip per TRU On-Site Truck Travel Distance 5 0.7 miles/round trip
On-Site Average Truck Travel Speed 6 5 miles/hourOn-Site Operational Time During Truck Trave 8.8 minutes/round trip per TRUOff-Site Truck Travel Distance 5 73.3 miles/round trip Off-Site Average Truck Travel Speed 6 30 miles/hourOff-Site Operational Time During Truck Trave 147 minutes/round trip per TRU Total Operational Time 8 170.4 minutes/TRUDaily Number of TRUs 9 4 TRUs/day Annual Number of TRUs 9 1,460 TRUs/year
Abbreviations:

ATCM - Airborne Toxic Control Measure PM10 - particulate matter less than 10 microns in diameter CARB - California Air Resources Board PM2.5 - particulate matter less than 2.5 microns in diameter CO - carbon monoxide SOx - sulfur oxide compounds
lbs - pounds TRU - transport refrigeration unitmin - minute VOC - volatile organic compounds NOx - nitrogen oxide compounds 9 The number of TRUs per day is based on Project-specific information. The total number of TRU uses per year was estimated by multiplying the daily number of TRUs by 365 operational days per year.3 The daily idle duration for delivery trucks is estimated as a product of idle duration per round trip and daily round trips. The idle duration per round trip is assumed to be 15 minutes (maximum 5 minutes at Project site entry, maximum 5 minutes at loading dock, and maximum 5 minutes at Project site exit), consistent with the CARB Air Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling.

Available at https://ww2.arb.ca.gov/our-work/programs/atcm-to-limit-vehicle-idling/about. Accessed: October 2025. 1 Daily TRU operational duration is estimated based on total operational time per TRU and the number of TRUs per day, as provided in the TRU Trip Information below.2 TRU emissions were estimated using emission factors from Table C-3 and the daily TRU operational duration.4 The on-site TRU operational time during truck idling is assumed to 15 minutes as described in footnote 3. TRUs will not idle for more than 5 minutes at the dock while unloading goods at the warehouse.5 The on-site warehouse delivery truck travel distance was estimated based on the proposed Project site layout. The off-site warehouse delivery truck travel distance was calculated by subtracting the on-site travel distance from the total trip length for the warehouse delivery truck. 6 The on-site and off-site average truck travel speed are consistent with CARB's assumptions in Appendix I of the Proposed Amendments to the ATCM Measure for In-Use Diesel-Fueled TRU and TRU Generator Sets, and Facilities Where TRUs Operate. Available at: https://ww2.arb.ca.gov/sites/default/files/barcu/board/rulemaking/tru2021/appi.pdf. Accessed: October 2025. 7 The on-site and off-site TRU operational time during warehouse delivery truck travel was calculated by dividing the on-site and off-site truck travel distances by their corresponding average truck travel speeds,respectively.8 The total operational time per TRU includes the operational time per round trip during on-site and off-site truck travel and on-site truck idling.