Frederick County, Maryland
AQI 41 · Good41
Median AQI
58
90th Percentile
93
Max AQI
237
Days with Data
Ranked #9 of 16 counties in Maryland (by median AQI, lower is better)
Monthly Median AQI — 2025
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41
Median AQI
58
90th Percentile
93
Max AQI
237
Days with Data
Ranked #9 of 16 counties in Maryland (by median AQI, lower is better)
Click a bar to view that month's details