Learn about the Air District’s California Environmental Quality Act Thresholds and Guidelines and how they help agencies evaluate air quality and greenhouse gas impacts from proposed projects and plans.
Update to the CEQA Thresholds of Significance for Climate Impacts
The Air District has adopted updated thresholds of significance for climate impacts. The Thresholds of Significance Justification Report(2 Mb PDF, 29 pgs, posted 04/21/22) 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. Updated CEQA Guidelines for applying these thresholds of significance will be coming soon.
If you would like to receive notifications and information on the update to the CEQA Guidelines or the CEQA Thresholds of Significance, please sign up on our CEQA Guidelines email list below.
CEQA Guidelines Email List
Subscribe
Current Air District CEQA Guidelines and Thresholds of Significance
On June 2, 2010, the Bay Area Air Quality Management District's Board of Directors unanimously adopted thresholds of significance to assist in the review of projects under the California Environmental Quality Act. These thresholds were designed to establish the level at which the Air District believed air pollution and greenhouse gas emissions would cause significant environmental impacts under CEQA. The thresholds were posted on the Air District’s website and included in the Air District's updated CEQA Guidelines (updated May 2012). The thresholds are advisory and may be followed by local agencies at their own discretion.
The thresholds were challenged in court. Following litigation in the trial court, the court of appeal, and the California Supreme Court, all of the thresholds were upheld. However, in an opinion issued on December 17, 2015, the California Supreme Court held that CEQA does not generally require an analysis of the impacts of locating development in areas subject to environmental hazards unless the project would exacerbate existing environmental hazards. The Supreme Court also found that CEQA requires the analysis of exposing people to environmental hazards in specific circumstances, including the location of development near airports, schools near sources of toxic contamination, and certain exemptions for infill and workforce housing. The Supreme Court also held that public agencies remain free to conduct this analysis regardless of whether it is required by CEQA.
In view of the Supreme Court’s opinion, local agencies may rely on thresholds designed to reflect the impact of locating development near areas of toxic air contamination where such an analysis is required by CEQA or where the agency has determined that such an analysis would assist in making a decision about the project. However, the thresholds are not mandatory and agencies should apply them only after determining that they reflect an appropriate measure of a project’s impacts.
The Guidelines for implementation of the thresholds are for information purposes only to assist local agencies. Recommendations in the Guidelines are advisory and should be followed by local governments at their own discretion. These Guidelines may inform environmental review for development projects in the Bay Area, but do not commit local governments or the Air District to any specific course of regulatory action.
The Air District published a new version of the Guidelines dated May 2017, which includes revisions made to address the Supreme Court’s opinion. The May 2017 Guidelines(5 Mb PDF, 224 pgs, posted 05/09/17) update does not address outdated references, links, analytical methodologies or other technical information that may be in the Guidelines or Thresholds Justification Report. The Air District is currently working to revise any outdated information in the Guidelines as part of its update to the CEQA Guidelines and thresholds of significance.
The table below includes the current version of the Air District’s CEQA Guidelines along with previous draft versions.
CEQA Guidelines Questions
If you have any questions about the CEQA guidelines and/or thresholds, please submit them below:
Submit Your Question