CEQA Tools

March 24, 2015
March 26 , 2015

CEQA Guide to Air Quality Assessment

Determine if a project will have significant air quality impacts by consulting the CEQA Guide to Air Quality Assessment (CEQA Guide). The CEQA Guide works in conjunction with the State CEQA Guidelines Appendix G.

The CEQA Guide provides methods to review air quality impacts (including greenhouse gases, Chapter 6) from development projects, screening approaches, methods for calculating emissions, and mitigation measures.

Additional information on mitigation measures is available on the AQMD’s mitigation page.

Guidance on assessing the potential increase in cancer risk from diesel exhaust by siting sensitive receptors adjacent to major roadways is available on the AQMD’s Roadway Protocol page.


For questions on specific projects, contact:

Staff Jurisdiction

Rachel Dubose

City of Citrus Heights, North and Central Areas of the County of Sacramento

J.J. Hurley

City of Folsom

Karen Huss

City of Galt, Flood Control Projects

Charlene McGhee

City of Elk Grove, South Area of the County of Sacramento

Paul Philley

City of Sacramento, Transportation Projects

Molly Wright City of Rancho Cordova
Staff contact information can be found on the AQMD’s staff directory (PDF).

Thresholds of Significance

The AQMD Board adopted the significance thresholds on March 28, 2002 (PDF). The significance thresholds are compiled in the CEQA Guide’s thresholds table (PDF).

On October 23, 2014, the AQMD Board adopted recommended greenhouse gas emissions (GHG) thresholds of significance (PDF). AQMD staff are currently working on updates to the CEQA Guide to incorporate the newly adopted thresholds.

Models and Meteorological Data

Models are commonly used to calculate project air emissions.

The California Emissions Estimator Model (CalEEMod) calculates both criteria pollutant and greenhouse gas emissions from land development projects. The model and user’s guide can be downloaded at

SMAQMD Tips for Using CalEEMod (PDF) (02/03/2015) is available to assist new model users in addition to the CalEEMod provided documents.

The AQMD has set April 1, 2013 as the date when agencies conducting air emissions analyses for land development projects for CEQA purposes must use CalEEMod.

In addition to CalEEMod, the Roadway Construction Emissions Model (Version, December 2013, in Excel - 5 Mb) is available to assess the emissions of linear construction projects.

For air dispersion modeling, the AQMD provides local meteorological data files (ASC) for the BEEST/ISCT3 model:

The following meteorological data files are available for the AERMOD air dispersion model:

  • Executive Airport 2010-2014 PFL and SFC files
    Exec10-14 N1MD (ZIP)
  • International Airport 2010-2014 PFL and SFC files
    Int10-14 N1MD (ZIP)

Contact Karen Huss ( or (916) 874-4881) regarding CalEEMod or Roadway Construction Emissions Model questions.