Counties with the Worst Air Quality in Pennsylvania
The top 25 of 38 Pennsylvania counties on GIS Map, ranked by median Air Quality Index, counting only counties that host an EPA air monitor.
| # | County | Median AQI |
|---|---|---|
| 1 | Allegheny County | 52 |
| 2 | Philadelphia County | 52 |
| 3 | Lancaster County | 50 |
| 4 | Dauphin County | 48 |
| 5 | Beaver County | 46 |
| 6 | Adams County | 44 |
| 7 | Washington County | 44 |
| 8 | York County | 44 |
| 9 | Berks County | 43 |
| 10 | Delaware County | 43 |
| 11 | Lebanon County | 43 |
| 12 | Cambria County | 42 |
| 13 | Fayette County | 42 |
| 14 | Armstrong County | 41 |
| 15 | Chester County | 41 |
| 16 | Centre County | 40 |
| 17 | Lackawanna County | 40 |
| 18 | Mercer County | 40 |
| 19 | Montgomery County | 40 |
| 20 | Lehigh County | 39 |
| 21 | Lycoming County | 39 |
| 22 | Northampton County | 39 |
| 23 | Westmoreland County | 39 |
| 24 | Erie County | 38 |
| 25 | Greene County | 38 |
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 Pennsylvania”, https://gismap.land/rankings/pennsylvania/worst-air-quality-counties. Figures from EPA Air Quality Index annual summary (2024).
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