SmogRank / World / United States / Massachusetts / December 2023

Most polluted cities in Massachusetts, United States, December 2023

15 cities in Massachusetts, United States ranked by their average PM2.5 over the 31 days. Worst: Greenfield at 9.8 µg/m³, #729 of 2,197 cities in the world. Cleanest: Ware at 4.1. 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.

← Greenfield 0% 0.75%0
Every city in Massachusetts, United States ranked for December 2023, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Greenfield
    0%
  2. 2Lexingtonlow-cost sensors
    0%
  3. 2Springfield
    0%
  4. 4North Adams
    0%
  5. 5North Chicopee
    0%
  6. 6Worcester
    0%
  7. 7Haverhill
    0%
  8. 7Pittsfield
    0%
  9. 9Brockton
    0%
  10. 9Lowell
    0%
  11. 11Boston
    0%
  12. 12Fall River
    0%
  13. 13Quincy
    0%
  14. 14Lynn
    0%
  15. 15Ware
    0%

Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.

Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

All cities in the world, December 2023 · All cities in United States, December 2023 · Massachusetts now

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SmogRank, most polluted cities in Massachusetts, United States, PM2.5, December 2023, smogrank.com/us/region/massachusetts/history/2023-12 (accessed 6 Oct 2026).

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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.