2005 Almanac (page 15)  Table 1-1
List of Counties in Each Air Basin

Great Basin Valleys Air Basin
Alpine County
Inyo County
Mono County

Lake County Air Basin
Lake County

Lake Tahoe Air Basin
El Dorado County (portion)
Placer County (portion)

Mojave Desert Air Basin
Kern County (portion)
Los Angeles County (portion)
Riverside County (portion)
San Bernardino County (portion)

Mountain Counties Air Basin
Amador County
Calaveras County
El Dorado County (portion)
Mariposa County
Nevada County
Placer County (portion)
Plumas County
Sierra County
Tuolumne County

North Central Coast Air Basin
Monterey County
San Benito County
Santa Cruz County

North Coast Air Basin
Del Norte County
Humboldt County
Mendocino County
Sonoma County (portion)
Trinity County

Northeast Plateau Air Basin
Lassen County
Modoc County
Siskiyou County

Sacramento Valley Air Basin
Butte County
Colusa County
Glenn County
Placer County (portion)
Sacramento County
Shasta County
Solano County (portion)
Sutter County
Tehama County
Yolo County
Yuba County

Salton Sea Air Basin
Imperial County
Riverside County (portion)

San Diego Air Basin
San Diego County

San Francisco Bay Area Air Basin
Alameda County
Contra Costa County
Marin County
Napa County
San Francisco County
San Mateo County
Santa Clara County
Solano County (portion)
Sonoma County (portion)

San Joaquin Valley Air Basin
Fresno County
Kern County (portion)
Kings County
Madera County
Merced County
San Joaquin County
Stanislaus County
Tulare County

South Central Coast Air Basin
San Luis Obispo County
Santa Barbara County
Ventura County

South Coast Air Basin
Los Angeles County (portion)
Orange County
Riverside County (portion)
San Bernardino County (portion)