Counties with the Worst Air Quality in New Hampshire
The top 7 of 7 New Hampshire counties on GIS Map, ranked by median Air Quality Index, counting only counties that host an EPA air monitor.
| # | County | Median AQI |
|---|---|---|
| 1 | Coos County | 44 |
| 2 | Rockingham County | 38 |
| 3 | Hillsborough County | 37 |
| 4 | Merrimack County | 37 |
| 5 | Cheshire County | 36 |
| 6 | Belknap County | 35 |
| 7 | Grafton County | 35 |
Source: EPA Air Quality Index annual summary (2024). All counties with data are ranked. Estimates carry margins of error.
Citing this page: GIS Map, “Counties with the Worst Air Quality in New Hampshire”, https://gismap.land/rankings/new-hampshire/worst-air-quality-counties. Figures from EPA Air Quality Index annual summary (2024).
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