SmogRank / World / United States / Massachusetts / 2025
Most polluted cities in Massachusetts, United States, 2025
16 cities in Massachusetts, United States ranked by their average PM2.5 over the 365 days; 16 above the WHO annual guideline (5.0 µg/m³). Worst: Greenfield at 6.8 µg/m³, #2,105 of 2,624 cities in the world. Cleanest: Ware at 5.1. A city needs measurements on 70% of the days to be ranked.
Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.
- 1Pittsfield 1%
- 2North Adams 1%
- 3Springfield 1%
- 4North Chicopee 1%
- 5Greenfield 1%
- 6Ware 1%
- 7Boston 0%
- 8Framingham 0%
- 9Haverhill 0%
- 10Brockton 0%
- 10Lowell 0%
- 10Worcester 0%
- 13Uxbridge 0%
- 14Fall River 0%
- 14Lynn 0%
- 14Quincy 0%
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
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SmogRank, most polluted cities in Massachusetts, United States, PM2.5, 2025, smogrank.com/us/region/massachusetts/history/2025 (accessed 6 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.