Air quality in Vermont
EPA monitors report from 4 of Vermont’s 14 counties. That is the honest limit of this page: the other 10 are not measured, not clean. In 2025 the most affected monitored county was Chittenden County, with 4 days above the moderate category.
4
Counties with monitors
10
Counties without
8
Days above moderate, 2025
Summed across monitored counties
11.1%
Adults with asthma
Population-weighted county estimate
County by county
Monitored Vermont counties
GoodModerateUnhealthy for sensitive groupsUnhealthyVery unhealthyHazardous
| County | 90th %ile AQI | Above moderate | Max AQI | 2025 days by category |
|---|---|---|---|---|
| Chittenden County | 55 | 4 | 156 | |
| Bennington County | 54 | 2 | 122 | |
| Rutland County | 58 | 1 | 130 | |
| Windham County | 48 | 1 | 117 |
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
10 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
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