State Standard Area Designations

This page last reviewed August 15, 2019


The Health and Safety Code (H&SC) section 39607(e) requires the Air Resources Board (Board) to establish and periodically review area designation criteria. These designation criteria provide the basis for the Board to designate areas of California as attainment, nonattainment, or unclassified for the State standards.The Board made the first area designations for State ambient air quality standards (State standards) in 1989. Since then, the ARB has reviewed the designations each year, making changes as needed. This web site area provides information about the ARB's activities related to the designation of areas in California with respect to the State standards.

In addition, H&SC section 39608 requires the Board to use the designation criteria to designate areas of California and to annually review those area designations. The Board makes area designations for ten pollutants: ozone, suspended particulate matter (PM10 and PM2.5), carbon monoxide, nitrogen dioxide, sulfur dioxide, sulfates, lead, hydrogen sulfide, and visibility reducing particles. Each year, the Board reviews the area designations and updates them as appropriate, based on the three most recent complete and validated calendar years of air quality data.

We have established an e-mail mailing list for Area Designation activities. As announcements, reports and other information are posted to this website, we will send e-mail notifications to everyone on the list. If you wish to receive these notices, you can subscribe by visiting the Area Designations Subscriber Page and following the instructions there.

Current Activities

On August 27, 2019, staff of the California Air Resources Board will host a webinar to present proposed amendments to the regulations designating areas of California as attainment, nonattainment, nonattainment-transitional, or unclassified for pollutants with State ambient air quality standards.  Information regarding the webinar can be found on the 2019 State Area Designations webpage.  

The amendments for the 2018 State Area Designations were approved by the Office of Administrative Law (OAL) on July 9, 2019 and became effective on that date.

Prior Activities

Summaries of changes in the State designations since 1989 are available, as well as links to Staff Reports documenting changes for previous years.

Maps and Tables

Maps of the current State area designations are available for downloading. These documents are in Adobe pdf format.