SmogRank / World / United States / Pennsylvania / May 2025
Most polluted cities in Pennsylvania, United States, May 2025
31 cities in Pennsylvania, United States ranked by their average PM2.5 over the 31 days. Worst: Philadelphia at 6.1 µg/m³, #1,860 of 2,771 cities in the world. Cleanest: Canonsburg at 3.7. 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.
- 1Philadelphia 0%
- 1Beaver Falls 0%
- 1West Mifflin 0%
- 4Bensalem 0%
- 5Hershey 0%
- 6Lebanon 0%
- 6New Holland 0%
- 8Kennett Square 0%
- 8Harrisburg 0%
- 8Pittsburgh 0%
- 11Lancaster 0%
- 11Wilkinsburg 0%
- 11Kennedy Township 0%
- 14Norristown 0%
- 15York 0%
- 16Jefferson Hills 0%
- 16New Brighton 0%
- 16Schlusser 0%
- 16Wyomissing 0%
- 20Altoona 0%
- 20Bethlehem 0%
- 20Greensburg 0%
- 20Monessen 0%
- 20Scranton 0%
- 25Allentown 0%
- 26Uniontown 0%
- 27Erie 0%
- 28Johnstown 0%
- 28State College 0%
- 30Hermitage 0%
- 31Canonsburg 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 Pennsylvania, United States, PM2.5, May 2025, smogrank.com/us/region/pennsylvania/history/2025-05 (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.