Skip to content
lung.com

Air quality in West Virginia

EPA monitors report from 14 of West Virginia’s 55 counties. That is the honest limit of this page: the other 41 are not measured, not clean. In 2025 the most affected monitored county was Hancock County, with 1 days above the moderate category.

14
Counties with monitors
41
Counties without
2
Days above moderate, 2025
Summed across monitored counties
12.2%
Adults with asthma
Population-weighted county estimate

County by county

Monitored West Virginia counties

GoodModerateUnhealthy for sensitive groupsUnhealthyVery unhealthyHazardous
County90th %ile AQIAbove moderateMax AQI2025 days by category
Hancock County641101
Monongalia County581105
Berkeley County54087
Brooke County57080
Cabell County58092
Gilmer County47071
Greenbrier County49077
Harrison County55068
Kanawha County55069
Marion County56071
Marshall County63081
Ohio County56097
Tucker County47071
Wood County54084

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

41 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