State Area Designations Definitions
This page updated June 2, 2003.
Geographic Extent of Designations
The size of the designated area may vary depending on the pollutant, the location of contributing emission sources, the meteorology, and the topographic features. The Board may designate areas smaller than an air basin or county, if the Board finds that a smaller area has distinctly different air quality.
- Air Basin:
is the area designated for ozone, nitrogen dioxide, PM10, sulfates, and
visibility reducing particles.
- County: (or the portion of a county located within an air basin) is the area designated for carbon monoxide, sulfur dioxide, lead, and hydrogen sulfide.
- See section 70300 through 70306 and Appendices 1 through 4 of the California Code of Regulations, Title 17)