SmogRank / World / United States / Pennsylvania / May 2023

Most unhealthy days in Pennsylvania, United States, May 2023

26 cities in Pennsylvania, United States ranked by their share of unhealthy days over the 31 days. The most unhealthy days: New Holland, United States, 0 of 29 measured days. 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.

← New Holland 0% 0.75%0
Every city in Pennsylvania, United States ranked for May 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. 1New Holland
    0 of 29
  2. 2Beaver Falls
    0 of 31
  3. 3Bensalem
    0 of 25
  4. 3West Mifflin
    0 of 31
  5. 5Philadelphia
    0 of 31
  6. 6Monessen
    0 of 31
  7. 7Lancaster
    0 of 31
  8. 8Harrisburg
    0 of 29
  9. 9Pittsburgh
    0 of 31
  10. 9Kennedy Township
    0 of 31
  11. 11York
    0 of 28
  12. 11Jefferson Hills
    0 of 31
  13. 13New Brighton
    0 of 27
  14. 14Lebanon
    0 of 31
  15. 15Schlusser
    0 of 31
  16. 16Kennett Square
    0 of 31
  17. 16Altoona
    0 of 28
  18. 18Johnstown
    0 of 31
  19. 18Norristown
    0 of 31
  20. 20Erie
    0 of 31
  21. 20Wyomissing
    0 of 31
  22. 22Bethlehem
    0 of 31
  23. 22State College
    0 of 28
  24. 24Allentown
    0 of 29
  25. 25Scranton
    0 of 31
  26. 26Hermitage
    0 of 28
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

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SmogRank, most polluted cities in Pennsylvania, United States, by unhealthy days, PM2.5, May 2023, smogrank.com/us/region/pennsylvania/history/2023-05?by=days (accessed 8 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.