Franklin County, Massachusetts

AQI 40 · Good

YearMonth

40

Median AQI

64

90th Percentile

114

Max AQI

243

Days with Data

Ranked #5 of 13 counties in Massachusetts (by median AQI, lower is better)

Monthly Median AQI — 2025

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AQI Category Breakdown

Adjacent Counties

Berkshire County Hampshire County Worcester County Cheshire County, New Hampshire Bennington County, Vermont Windham County, Vermont

External Links

Franklin County, Massachusetts on Wikipedia