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Counties with the Cleanest Air in Colorado

The top 25 of 30 Colorado counties on GIS Map, ranked by lowest median Air Quality Index, counting only counties that host an EPA air monitor.

#CountyMedian AQI
1San Juan County
9
2Routt County
12
3Fremont County
13
4Pitkin County
19
5San Miguel County
19
6Prowers County
25
7Alamosa County
26
8Archuleta County
32
9Jackson County
44
10Pueblo County
44
11Grand County
45
12Montezuma County
45
13La Plata County
46
14Rio Blanco County
46
15Gunnison County
47
16Douglas County
48
17Gilpin County
48
18Mesa County
48
19Arapahoe County
49
20Boulder County
49
21Clear Creek County
49
22El Paso County
49
23Garfield County
49
24Jefferson County
50
25Park County
50

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

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