CEQA Thresholds and Guidelines Update

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Update to the CEQA Thresholds of Significance for Climate Impacts

On April 20, 2022, the Air District Board of Directors adopted CEQA Thresholds for Evaluating the Significance of Climate Impacts from Land Use Projects and Plans. (For more information, please see the April 20, 2022, Board of Directors Agenda and Presentation.) Appendix B of the Guidelines, CEQA Thresholds for Evaluating the Significance of Climate Impacts, presents the Air District’s thresholds of significance for use in determining whether a proposed project will have a significant impact on climate change and provides the substantial evidence that lead agencies will need to support their use of these thresholds.

2022 CEQA Guidelines

Land use projects and plans have the potential to generate air pollutants (and precursors) that contribute to the degradation of regional air quality, increase the exposure of local populations to harmful pollutants, and contribute to climate change.

The purpose of the Air District’s CEQA Guidelines is to assist lead agencies in evaluating air quality and climate impacts from proposed land use projects and plans in the San Francisco Bay Area Air Basin. The Guidelines include nonbinding recommendations for how a lead agency can evaluate, measure, and mitigate air quality and climate impacts generated from land use construction and operational activities.

The Air District is committed to timely updates to ensure the Guidelines reflect best available information, methods, and data as well as user feedback. Any future updates to the Guidelines will also be nonbinding and advisory.

The Guidelines do not replace the State CEQA Statute and Guidelines; rather, they are designed to provide Air District-recommended procedures for evaluating potential air quality and climate impacts during the environmental review process that are consistent with CEQA requirements. The revised Guidelines supersede the Air District’s previous CEQA guidance titled BAAQMD CEQA Air Quality Guidelines (BAAQMD 2017).

Frequently Asked Questions

2022 CEQA Guidelines Chapters

Cover Page and Table of Contents(1 Mb PDF, 14 pgs, revised 4/20/2023)

Chapter 1, “Introduction”(1 Mb PDF, 6 pgs, revised 4/20/2023) 
The Introduction provides a summary of the purpose of the Guidelines, an overview of Air District responsibilities, and a summary of the Guidelines’ components.

Chapter 2, “Best Practices for Centering Environmental Justice, Health and Equity”(1 Mb PDF, 24 pgs, revised 4/20/2023) 
The purpose of this chapter is to provide lead agencies with best practices on centering Environmental Justice, health, and equity in the siting, design, and development of land use projects.

Chapter 3, “Thresholds of Significance”(862 Kb PDF, 8 pgs, revised 4/20/2023) 
This chapter outlines the current thresholds of significance for determining the significance of air pollutants and climate impacts.

Chapter 4, “Screening for Criteria Air Pollutants and Precursors”(824 Kb PDF, 6 pgs, revised 4/20/2023) 
This chapter provides easy-reference tables to determine whether projects may have potentially significant criteria air pollutant impacts requiring a detailed analysis.

Chapter 5, “Project-Level Air Quality Impacts”(1 Mb PDF, 20 pgs, revised 4/25/2023)
This chapter provides guidance on how to conduct an air quality analysis at the project level, as well as a project-level cumulative impact analysis.

Chapter 6, “Project-Level Climate Impacts”(975 Kb PDF, 12 pgs, revised 11/2/2023) 
This chapter provides guidance on applying the Air District’s thresholds of significance for climate impacts from GHG emissions to projects, including land use and stationary source projects.

Chapter 7, “Plan-Level Impacts”(855 Kb PDF, 6 pgs, revised 4/20/2023) 
This chapter presents guidance on conducting plan-level air quality impacts and applying plan-level climate impact thresholds to plans.

Chapter 8, “Mitigating Air Quality and Climate Impacts”(826 Kb PDF, 8 pgs, revised 4/20/2023) 
This chapter provides recommendations for mitigating air quality and climate impacts for land use plans and projects.

2022 CEQA Guidelines Appendices

Appendix A, “Thresholds of Significance Justification”(4 Mb PDF, 70 pgs, revised 4/20/2023) 
This appendix is the Air District’s 2010 Thresholds of Significance document explaining the rationale for the air quality thresholds.

Appendix B, “CEQA Thresholds for Evaluating the Significance of Climate Impacts”(2 Mb PDF, 30 pgs, revised 11/2/2023) 
This appendix presents the rationale for the Air District’s recommended thresholds of significance for use in determining whether a proposed project will have a significant impact on climate change.

Appendix C, “Guidance for Greenhouse Gas Reduction Strategies”(1 Mb PDF, 24 pgs, revised 4/20/2023) 
This appendix is designed to assist users in developing community-scale greenhouse gas (GHG) reduction strategies that are aligned with the State CEQA Guidelines Section 15183.5(b)(1) and (2) and meet the Air District’s plan-level GHG threshold of significance.

Appendix D, “Using CalEEMod for Bay Area Projects"(5 Mb PDF, 46 pgs, revised 4/20/2023) 
This appendix provides guidance on using the California Emissions Estimator Model (CalEEMod) modeling tool for Bay Area projects.

Appendix E, “Recommended Methods for Screening and Modeling Local Risks and Hazards”(2 Mb PDF, 124 pgs, posted 8/28/2023)
This appendix provides guidance for conducting individual project and cumulative cancer risk and hazards analysis as part of their environmental review.

Appendix F(1 Mb PDF, 8 pgs, revised 4/20/2023) 
Glossary of terms used throughout this guide.

Mixed Land Use Screening Tool for Criteria Pollutants and Precursors(118 Kb, posted 4/7/2023)
This Excel-based tool provides CEQA lead agencies with a conservative indication of whether implementing a proposed mixed land use project could result in potentially significant criteria air pollutants and precursors impacts.

Archived Guidelines

• Archive of Previous CEQA Guidelines

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