Air Quality by State

Coverage spans all 50 U.S. states and DC, average air quality metrics across all 53 jurisdictions, based on EPA Air Quality System (AQS) county-level monitoring data for 2020-2025. Data from the EPA Air Quality System (AQS) and AirNow, covering all 50 states; see our methodology.

National air-quality trend strip across 53 states Sparkline-style distribution of average good-pct across all states, sorted high to low. National good-day distribution 53 states · sorted high → low % good days
53 U.S. states monitoring station coverage Grid of county tiles for 53 U.S. states, color-encoded by good-air-quality share, with antenna icons marking counties hosting active EPA AQS monitoring stations. Monitoring station coverage 48 of 53 counties · 90.6% covered Tile color = good-day share 90%+ 75%+ 50%+ 25%+ <25% 53 U.S. states · counties shown: 48
48 actively-monitored counties · 90.6% of 53 U.S. states coverage
State Counties Avg Good % Avg Median AQI
Alabama 15 77.2% 40
Alaska 8 89.1% 20
Arizona 13 61.2% 44
Arkansas 11 66.9% 45
California 46 64.3% 45
Colorado 27 69.8% 39
Connecticut 8 76.4% 42
Delaware 3 70.1% 44
District of Columbia 1 68.1% 45
Florida 38 75.1% 41
Georgia 26 68.7% 43
Hawaii 3 90.8% 28
Idaho 19 85.1% 30
Illinois 23 70.5% 43
Indiana 33 71.0% 42
Iowa 15 67.4% 43
Kansas 12 77.1% 38
Kentucky 25 83.9% 40
Louisiana 22 74.5% 41
Maine 11 86.8% 36
Maryland 16 82.4% 41
Massachusetts 13 78.8% 40
Michigan 27 81.1% 37
Minnesota 22 87.8% 33
Mississippi 10 72.6% 43
Missouri 21 82.2% 40
Montana 23 90.6% 23
Nebraska 10 83.6% 31
Nevada 9 73.6% 40
New Hampshire 7 84.6% 38
New Jersey 15 76.4% 41
New Mexico 16 72.2% 35
New York 27 81.5% 38
North Carolina 34 82.0% 40
North Dakota 9 77.7% 40
Ohio 37 68.6% 44
Oklahoma 20 68.6% 44
Oregon 21 82.8% 29
Pennsylvania 37 73.5% 40
Puerto Rico 8 88.4% 21
Rhode Island 3 78.5% 39
South Carolina 13 71.6% 44
South Dakota 10 80.7% 36
Tennessee 23 80.3% 39
Texas 45 64.9% 42
Utah 17 65.4% 42
Vermont 4 88.2% 32
Virgin Islands 1 100.0% 18
Virginia 30 86.1% 36
Washington 31 87.9% 27
West Virginia 13 78.7% 39
Wisconsin 29 80.5% 39
Wyoming 17 83.3% 32