Insights: Hartford-West Hartford-East Hartford, CT metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 42 over 365 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 243 Good days (67%), 111 Moderate (30%), and 9 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 72 while the highest single-day reading hit 164 (Unhealthy). Metro residents averaged roughly 20.0 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by +1.0 points and the median AQI moved -1 points, which classifies the multi-year trajectory as stable. The annual record contains 2 days at Unhealthy or worse. On those days, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Metros with comparable AQI profiles include Allentown-Bethlehem-Easton, PA-NJ (66.8% good, AQI 42); Amarillo, TX (78.4% good, AQI 42); Carson City, NV (86.2% good, AQI 42).