Montgomery County, Maryland

AQI 41 · Good

YearMonth

41

Median AQI

54

90th Percentile

90

Max AQI

303

Days with Data

Ranked #11 of 16 counties in Maryland (by median AQI, lower is better)

Monthly Median AQI — 2025

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AQI Category Breakdown

Adjacent Counties

District of Columbia County, District of Columbia Frederick County Howard County Prince George's County Fairfax County, Virginia Loudoun County, Virginia

External Links

Montgomery County, Maryland on Wikipedia