Air quality history by state
EPA has reported daily AQI summaries for 1,536 counties and county-equivalents. Pick a state to compare its monitored counties.
- Alabama 31 counties
- Alaska 16 counties
- Arizona 15 counties
- Arkansas 26 counties
- California 58 counties
- Colorado 40 counties
- Connecticut 8 counties
- Delaware 3 counties
- District of Columbia 1 counties
- Florida 42 counties
- Georgia 39 counties
- Guam 1 counties
- Hawaii 4 counties
- Idaho 31 counties
- Illinois 33 counties
- Indiana 53 counties
- Iowa 26 counties
- Kansas 23 counties
- Kentucky 55 counties
- Louisiana 30 counties
- Maine 17 counties
- Maryland 19 counties
- Massachusetts 13 counties
- Michigan 53 counties
- Minnesota 40 counties
- Mississippi 29 counties
- Missouri 34 counties
- Montana 36 counties
- Nebraska 24 counties
- Nevada 12 counties
- New Hampshire 10 counties
- New Jersey 20 counties
- New Mexico 21 counties
- New York 39 counties
- North Carolina 62 counties
- North Dakota 15 counties
- Ohio 58 counties
- Oklahoma 45 counties
- Oregon 26 counties
- Pennsylvania 44 counties
- Puerto Rico 22 counties
- Rhode Island 3 counties
- South Carolina 28 counties
- South Dakota 14 counties
- Tennessee 42 counties
- Texas 63 counties
- Utah 19 counties
- Vermont 7 counties
- Virgin Islands 3 counties
- Virginia 60 counties
- Washington 34 counties
- West Virginia 20 counties
- Wisconsin 48 counties
- Wyoming 21 counties
Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem