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RankingsIdahoWorst air quality

Counties with the Worst Air Quality in Idaho

The top 20 of 20 Idaho counties on GIS Map, ranked by median Air Quality Index, counting only counties that host an EPA air monitor.

#CountyMedian AQI
1Boise County
48
2Shoshone County
46
3Ada County
44
4Benewah County
43
5Butte County
42
6Idaho County
42
7Bannock County
39
8Lemhi County
37
9Valley County
37
10Canyon County
36
11Bonner County
32
12Nez Perce County
29
13Latah County
27
14Kootenai County
24
15Twin Falls County
23
16Bonneville County
22
17Franklin County
22
18Blaine County
19
19Boundary County
17
20Custer County
6

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

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