SmogRank / World / United States / Pennsylvania / 2026
Most polluted cities in Pennsylvania, United States, 2026
34 cities in Pennsylvania, United States ranked by their average PM2.5 so far (278 of 365 days); 34 above the WHO annual guideline (5.0 µg/m³). Worst: York at 11.2 µg/m³, #789 of 2,745 cities in the world. Cleanest: Altoona at 7.3. 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.
- 1New Holland 3%
- 2York 2%
- 3Schlusser 1%
- 4Beaver Falls 1%
- 5Lebanon 1%
- 6Wyomissing 1%
- 7Lancaster 1%
- 8New Brighton 1%
- 9Harrisburg 1%
- 10West Mifflin 1%
- 11Bensalem 1%
- 12Bethlehem 1%
- 13Warren 1%
- 14Greensburg 1%
- 15Altoona 1%
- 16State College 1%
- 17Hermitage 1%
- 18Uniontown 1%
- 19Norristown 1%
- 20Monessen 1%
- 21Bridgeville 1%
- 22Kennedy Township 1%
- 23Kennett Square 1%
- 24Jefferson Hills 1%
- 25Wilkinsburg 1%
- 26Pittsburgh 1%
- 27Johnstown 1%
- 28Erie 1%
- 29Canonsburg 1%
- 30Philadelphia 1%
- 31Natrona Heights 1%
- 32Scranton 1%
- 33Hershey 1%
- 34Allentown 1%
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, 2026 (so far), smogrank.com/us/region/pennsylvania/history/2026 (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.