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RankingsMarylandWorst air quality

Counties with the Worst Air Quality in Maryland

The top 15 of 15 Maryland counties on GIS Map, ranked by median Air Quality Index, counting only counties that host an EPA air monitor.

#CountyMedian AQI
1Baltimore County
45
2Cecil County
44
3Frederick County
43
4Carroll County
42
5Harford County
42
6Calvert County
41
7Anne Arundel County
40
8Charles County
40
9Dorchester County
40
10Kent County
40
11Montgomery County
40
12Washington County
40
13Garrett County
39
14Prince George's County
39
15Howard County
32

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 Maryland”, https://gismap.land/rankings/maryland/worst-air-quality-counties. Figures from EPA Air Quality Index annual summary (2024).

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