RANKABLE EPA COUNTY AQI
Custer Air Quality - Montana
EPA county-level evidence, NDS comparative intelligence, and 5 connected ZIP profiles.
Median AQI
39.0
Maximum AQI
95.0
Good-air-quality days
91.16%
Average PM2.5
4.723 ug/m3
NDS Air Quality Score
67.58
U.S. County Rank
282 of 1,049
Percentile
73.09
Grade
B
County status
Custer is part of the governed NDS rankable EPA county universe.
Methodology
EPA AQI evidence used here is county-derived. ZIP profiles connect to this evidence through the governed NDS geography relationship.