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RankingsIllinoisCleanest air

Counties with the Cleanest Air in Illinois

The top 23 of 23 Illinois counties on GIS Map, ranked by lowest median Air Quality Index, counting only counties that host an EPA air monitor.

#CountyMedian AQI
1Macoupin County
35
2Clark County
36
3Jo Daviess County
36
4Lake County
40
5Randolph County
40
6Effingham County
41
7Sangamon County
41
8Adams County
42
9Jersey County
42
10Kane County
42
11Macon County
43
12McHenry County
43
13Winnebago County
43
14Champaign County
44
15Hamilton County
44
16McLean County
44
17Peoria County
44
18Rock Island County
44
19Will County
44
20DuPage County
45
21St. Clair County
46
22Madison County
49
23Cook County
54

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 Cleanest Air in Illinois”, https://gismap.land/rankings/illinois/cleanest-air-counties. Figures from EPA Air Quality Index annual summary (2024).

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