Days exceeding air quality standards

Select one of the air basins below and then click the "select basin" button.

Select basin
  1. San Joaquin Valley (Fresno, part of Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, Tulare)
  2. Great Basin Valleys (Alpine, Inyo, Mono)
  3. Lake County
  4. Lake Tahoe (Part of El Dorado, part of Placer)
  5. Mojave Desert (Part of Kern, part of Los Angeles, part of Riverside, part of San Bernardino)
  6. Mountain Counties (Amador, Calaveras, part of El Dorado, Mariposa, Nevada, part of Placer, Plumas, Sierra, Tuolumne)
  7. North Central Coast (San Benito, Santa Cruz, Monterey)
  8. North Coast (Del Norte, Humboldt, Mendocino, part of Sonoma, Trinity)
  9. Northeast Plateau (Lassen, Modoc, Siskiyou)
  10. Sacramento Valley (Butte, Colusa, Glenn, part of Placer, Sacramento, Shasta, part of Solano, Sutter, Tehama, Yolo, Yuba)
  11. Salton Sea (Imperial, part of Riverside)
  12. San Diego County
  13. San Francisco Bay (Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, part of Solano, part of Sonoma)
  14. South Central Coast (San Luis Obispo, Santa Barbara, Ventura)
  15. South Coast (Part of Los Angeles, Orange, part of Riverside, part of San Bernardino)