Insights: Harrisburg-Carlisle, PA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 44 over 212 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 128 Good days (60%), 84 Moderate (40%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 64 while the highest single-day reading hit 93 (Moderate). Metro residents averaged roughly 18.1 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -82 and the median AQI moved -4 points, which classifies the multi-year trajectory as stable. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Athens-Clarke County, GA (66.7% good, AQI 44); Bartlesville, OK (65.6% good, AQI 44); Bloomington, IL (64.1% good, AQI 44).