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Air quality in Kentucky

EPA monitors report from 26 of Kentucky’s 120 counties. That is the honest limit of this page: the other 94 are not measured, not clean. In 2025 the most affected monitored county was Jefferson County, with 10 days above the moderate category.

26
Counties with monitors
94
Counties without
21
Days above moderate, 2025
Summed across monitored counties
11.1%
Adults with asthma
Population-weighted county estimate

County by county

Monitored Kentucky counties

GoodModerateUnhealthy for sensitive groupsUnhealthyVery unhealthyHazardous
County90th %ile AQIAbove moderateMax AQI2025 days by category
Jefferson County6710153
Campbell County574122
Boone County543108
Oldham County512108
Bell County591101
Perry County521172
Boyd County54097
Bullitt County54090
Carter County51082
Christian County57087
Daviess County61084
Edmonson County49077
Fayette County570100
Greenup County46067
Hancock County58097
Hardin County58097
Jessamine County570100
Livingston County51093
McCracken County58097
Morgan County47087
Pike County52077
Pulaski County54073
Simpson County49074
Trigg County50080
Warren County54073
Washington County50097

EPA Air Quality System annual summaries by county, 2025. The 90th percentile AQI describes a day worse than nine out of ten, which is a steadier measure than the annual maximum a single wildfire can set.

Not measured

94 counties without a monitor

No EPA monitor reported from these counties, so there is no air quality record to publish. Their radon zone is known, and radon is measured in the building rather than the air outside it.

Other states

Air quality elsewhere