Out of 58 counties with wildfire data, these are the counties with the highest smoke exposure risk.
| Statistic | Value |
|---|---|
| Counties ranked | 58 |
| Avg smoke risk (top 100) | 44/100 |
| Total county fires 5yr (top 100) | 2,795 |
Top 58 Counties
| Rank | County | State | Smoke Risk | County Fires (5yr) | ZIP Codes |
|---|---|---|---|---|---|
| 1 | Riverside | California | 96/100 | 157 | 101 |
| 2 | Los Angeles | California | 88/100 | 117 | 459 |
| 3 | San Diego | California | 83/100 | 170 | 187 |
| 4 | San Bernardino | California | 77/100 | 150 | 114 |
| 5 | Inyo | California | 66/100 | 150 | 42 |
| 6 | Kern | California | 65/100 | 298 | 102 |
| 7 | Madera | California | 65/100 | 157 | 16 |
| 8 | Tuolumne | California | 59/100 | 58 | 16 |
| 9 | Mariposa | California | 58/100 | 58 | 6 |
| 10 | Calaveras | California | 53/100 | 12 | 16 |
| 11 | Siskiyou | California | 52/100 | 102 | 19 |
| 12 | Ventura | California | 52/100 | 54 | 44 |
| 13 | Shasta | California | 52/100 | 37 | 31 |
| 14 | Butte | California | 50/100 | 117 | 29 |
| 15 | Plumas | California | 50/100 | 101 | 14 |
| 16 | Fresno | California | 50/100 | 41 | 102 |
| 17 | Orange | California | 50/100 | 6 | 143 |
| 18 | Lake | California | 50/100 | 6 | 21 |
| 19 | Trinity | California | 49/100 | 48 | 10 |
| 20 | Nevada | California | 49/100 | 16 | 14 |
| 21 | Monterey | California | 49/100 | 6 | 36 |
| 22 | Tulare | California | 48/100 | 41 | 36 |
| 23 | Santa Barbara | California | 46/100 | 31 | 40 |
| 24 | El Dorado | California | 46/100 | 20 | 24 |
| 25 | Amador | California | 45/100 | 20 | 18 |
| 26 | Sierra | California | 44/100 | 12 | 7 |
| 27 | Tehama | California | 43/100 | 9 | 14 |
| 28 | Alpine | California | 42/100 | 20 | 5 |
| 29 | Santa Cruz | California | 41/100 | 6 | 22 |
| 30 | Sonoma | California | 41/100 | 5 | 63 |
| 31 | Placer | California | 40/100 | 20 | 31 |
| 32 | Mendocino | California | 40/100 | 4 | 29 |
| 33 | Humboldt | California | 39/100 | 102 | 41 |
| 34 | Modoc | California | 39/100 | 65 | 9 |
| 35 | Yuba | California | 39/100 | 16 | 13 |
| 36 | Mono | California | 38/100 | 16 | 6 |
| 37 | Glenn | California | 37/100 | 37 | 12 |
| 38 | Napa | California | 37/100 | 3 | 13 |
| 39 | Del Norte | California | 36/100 | 31 | 9 |
| 40 | Lassen | California | 35/100 | 101 | 18 |
| 41 | San Luis Obispo | California | 35/100 | 21 | 34 |
| 42 | Merced | California | 34/100 | 10 | 22 |
| 43 | San Benito | California | 34/100 | 6 | 5 |
| 44 | Imperial | California | 32/100 | 150 | 22 |
| 45 | Stanislaus | California | 32/100 | 6 | 26 |
| 46 | Colusa | California | 32/100 | 2 | 5 |
| 47 | Sacramento | California | 30/100 | 1 | 133 |
| 48 | Santa Clara | California | 29/100 | 5 | 104 |
| 49 | Contra Costa | California | 27/100 | 5 | 35 |
| 50 | San Joaquin | California | 26/100 | 117 | 55 |
| 51 | Solano | California | 26/100 | 5 | 18 |
| 52 | Alameda | California | 25/100 | 5 | 75 |
| 53 | Yolo | California | 25/100 | 0 | 19 |
| 54 | Kings | California | 24/100 | 41 | 9 |
| 55 | Sutter | California | 23/100 | 0 | 7 |
| 56 | San Mateo | California | 22/100 | 1 | 35 |
| 57 | Marin | California | 19/100 | 0 | 33 |
| 58 | San Francisco | California | 12/100 | 0 | 59 |
Methodology
County rankings for California based on average smoke risk score and fire frequency.
Data sources: National Interagency Fire Center (NIFC), EPA AirNow. Last updated: 2026-06-04.
Frequently Asked Questions
How is wildfire smoke risk calculated?
Smoke risk scores (0-100) combine multiple factors: proximity to recent wildfires, county fire frequency over the past 5 years, historical smoke days, and geographic position relative to typical fire corridors. Higher scores indicate greater smoke exposure risk during fire season.
How can I protect myself from wildfire smoke?
Use a HEPA air purifier indoors, wear N95 or KN95 masks outdoors during smoke events, seal windows and doors, and monitor AirNow.gov for real-time air quality. Create a clean room in your home with the purifier running and windows sealed.