SmogRank / United States / Pennsylvania / Hershey
Hershey, month by month
Hershey has a measured daily mean on 848 days since 25 May 2024. Its worst month was February 2026, at 62 US AQI (15.2 µg/m³), 768th of 2,866 cities on that month's world ranking. Its cleanest was October 2025, at 29 US AQI (5.2 µg/m³).
Every month since 2024
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
Months without a mean, and why
1 month
| Month | Why |
|---|---|
| May 2024 | 7 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Hershey's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2026 | 6215.2 µg/m³ | 768thof 2,866 | North-eastern United States and Canada, 14 to 19 February 2026 Pennsylvania, United States, February 2026 |
| July 2026 | 6014.0 µg/m³ | 596thof 2,784 | Northern United States and Canada, July 2026 North-eastern United States, June and July 2026 |
| June 2025 | 5611.7 µg/m³ | 861stof 2,508 | Northern United States and Canada, June 2025 |
| August 2024 | 5310.4 µg/m³ | 551stof 2,010 | – |
| December 2024 | 5310.2 µg/m³ | 866thof 2,616 | South-eastern Canada and United States, December 2024 |
| January 2025 | 5310.1 µg/m³ | 981stof 2,474 | Pennsylvania and Delaware, United States, January 2025 |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Hershey's worst days
Daily means, the highest since 25 May 2024; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Hershey, United States, 25 May 2024 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/hershey/history (accessed 12 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.
Hershey now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 17:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).