PlainAirData · EPA AQS 2025

Cleanest air, top counties

Annual good-day share among counties with ≥100 monitored days. Not a live AQI advisory.

1. 1 Karnes, Texas 100.0%
2. 2 Wilson, Texas 100.0%
3. 3 Carbon, Wyoming 100.0%
4. 4 Kenai Peninsula, Alaska 100.0%
5. 5 Sonoma, California 100.0%
6. 6 Uinta, Wyoming 100.0%
7. 7 Martin, North Carolina 100.0%
8. 8 Pacific, Washington 99.7%
9. 9 Denali, Alaska 99.7%
10. 10 Navajo, Arizona 99.5%

Source: PlainAirData best-air ranking, derived from EPA AQS Annual AQI by County (2025). CC BY 4.0 with attribution.