| # | County | Median AQI |
|---|---|---|
| 1 | Cuyahoga County | 54 |
| 2 | Butler County | 53 |
| 3 | Franklin County | 53 |
| 4 | Hamilton County | 52 |
| 5 | Lucas County | 52 |
| 6 | Stark County | 48 |
| 7 | Montgomery County | 47 |
| 8 | Clark County | 45 |
| 9 | Jefferson County | 45 |
| 10 | Trumbull County | 45 |
| 11 | Clinton County | 44 |
| 12 | Madison County | 44 |
| 13 | Mahoning County | 44 |
| 14 | Medina County | 44 |
| 15 | Preble County | 44 |
| 16 | Summit County | 44 |
| 17 | Greene County | 43 |
| 18 | Lawrence County | 43 |
| 19 | Miami County | 43 |
| 20 | Portage County | 43 |
| 21 | Warren County | 43 |
| 22 | Allen County | 42 |
| 23 | Delaware County | 42 |
| 24 | Licking County | 42 |
| 25 | Ashtabula County | 41 |
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 Ohio”, https://gismap.land/rankings/ohio/worst-air-quality-counties. Figures from EPA Air Quality Index annual summary (2024).
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