Air quality · Pennsylvania
Air quality in Pennsylvania
Across the 10 Pennsylvania ZIPs with EPA county air-quality data, the median day ranges from Good to Moderate (median AQI 35–52). No day in those counties reached Unhealthy in 2025. This is a 2025 county annual summary, not a live reading.
Last verified 2026-09-24 · methodology
Air quality by ZIP code in Pennsylvania
EPA's 2025 annual summary for each ZIP's county. Median AQI is the typical day; lower is cleaner.
| ZIP | Median AQI | Good days | Unhealthy or worse |
|---|---|---|---|
| 19103PhiladelphiaPhiladelphia County | 50 Good | 184 of 365 | 0 |
| 15222PittsburghAllegheny County | 52 Moderate | 168 of 365 | 0 |
| 17101HarrisburgDauphin County | 44 Good | 228 of 365 | 0 |
| 16801State CollegeCentre County | 41 Good | 271 of 365 | 0 |
| 15217Pittsburgh (Squirrel Hill)Allegheny County | 52 Moderate | 168 of 365 | 0 |
| 17013CarlisleCumberland County | 35 Good | 261 of 365 | 0 |
| 19610WyomissingBerks County | 43 Good | 249 of 365 | 0 |
| 15601Greensburg (PA)Westmoreland County | 39 Good | 283 of 362 | 0 |
| 17110Harrisburg (PA)Dauphin County | 44 Good | 228 of 365 | 0 |
| 18103Allentown (PA)Lehigh County | 41 Good | 260 of 361 | 0 |
County-level figures from EPA Air Quality System (AQS), annual county summary, joined to each ZIP by county. None of them is a measurement at a specific address.
What lands here
Pages show the 2025 median AQI category (Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, Hazardous) for the ZIP's county, plus the year's max/90th-percentile AQI and day-count breakdown by category.
Source & refresh
EPA Air Quality System (AQS), annual county summary. Refreshed annual (epa aqs publication). Primary source →
Pennsylvania top concern
Radon, lead pipes (older cities)
Pennsylvania has Zone 1 radon across most of the state. LCRR lead-service-line obligations in Philadelphia, Pittsburgh, Reading, Allentown, Erie. EPA SDWIS small-system compliance varies.
See Pennsylvania state page for the full state-level rollup across all 12 dimensions.
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