South Coast AQMD is in the process of developing an "Air Quality Analysis Guidance Handbook" (Handbook) to replace the CEQA Air Quality Handbook approved by the South Coast AQMD Governing Board in 1993.  The 1993 CEQA Air Quality Handbook is still available but not online. To obtain a hardcopy of the 1993 Handbook, contact South Coast AQMD's Subscription Services at (909) 396-3720. In addition, there are sections of the 1993 Handbook that are obsolete. A description of the obsolete sections can be obtained from CEQA Air Quality Handbook.

In order to assist the CEQA practitioner in conducting an air quality analysis while the new Handbook is being prepared, the following supplemental information is available:

Air Quality Significance Thresholds and Analysis

• South Coast AQMD Air Quality Significance Thresholds (Updated March 2023)                                                                                                                                        NOTE: The South Coast AQMD air quality significance thresholds were updated in March 2023 to reflect the U.S. EPA's redesignation of the Coachella Valley from Severe-15 to Extreme non-attainment for the 2008 ozone national ambient air quality standards (NAAQS). Please see the following link for more information:   U.S. EPA-Designation of Areas for Air Quality Planning Purposes; California; Coachella Valley Ozone Nonattainment Area; Reclassification to Extreme

• Greenhouse Gases (GHG) CEQA Significance Thresholds

• Localized Significance Thresholds

• PM 2.5 Significance Thresholds and Calculation Methodology

Emission Factors

• Off-Road - OFFROAD Model Mobile Source Emission Factors

• On-Road - EMFAC 2007 (v2.3) Emission Factors

• Toxic Emission Factors from Combustion Sources

Cumulative Impacts Emission Analysis

• Potential Control Strategies to Address Cumulative Impacts from Air Pollution White Paper 

  • Appendices 

Future CO Concentrations

The following documents provide CO emissions and projected future concentrations in order to assist the CEQA practitioner with a CO Hotspots Analysis.

• Average Annual Day CO Emission in the South Coast Air Basin

• Projected Future Year 1-Hour Concentration (ppm) 

• Projected Future Year 8-Hour Concentration (ppm)

Air Toxics Analysis

• Mobile Source Toxics Analysis

• Risk Assessment Procedures for Rules 1401 and 212

Air Quality Guidance for General Plans, Local Planning, and School Siting

• Guidance Document for Addressing Air Quality Issues in General Plans, Local Planning, and School Siting

High Cube Warehouse Trip Rate Study for Air Quality Analysis

• Study Home Page

Mitigation Measures

• Mitigation Measures and Control Efficiencies

• CAPCOA- Quantifying Greenhouse Gas Mitigation Measures (PDF, 7.7MB)

Other Useful Links

• Guidance on Frequently Questioned Topics in Roadway Analysis for the California Environmental Quality Act (CEQA)

• Western Riverside Council of Governments' Good Neighbor Guidelines for Siting New and/or Modified Warehouse/Distribution Facilities

• Guidance Document for Addressing Air Quality Issues in General Plans and Local Planning

• California Air Resources Board Air Quality and Land Use Handbook: A Community Health Perspective

• Pilot Study of High Performance Air Filtration for Classroom Applications