SmogRank / World / United States / Connecticut / 2023
Most polluted cities in Connecticut, United States, 2023
6 cities in Connecticut, United States ranked by their average PM2.5 over the 365 days; 6 above the WHO annual guideline (5.0 µg/m³). Worst: Bridgeport at 9.4 µg/m³, #569 of 1,302 cities in the world. Cleanest: New London at 7.8. A city needs measurements on 70% of the days to be ranked.
OpenAQ's archive, where our readings come from, has almost none for 56 of these 365 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.
About 1.66K people in this city breathed unhealthy air on an average day of 2023.
Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.
- 1Hartford 1.66K
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 Connecticut, United States, PM2.5, 2023, smogrank.com/us/region/connecticut/history/2023 (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.