Insights: Chattanooga, TN-GA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 49 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 186 Good days (51%), 174 Moderate (48%), and 3 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 65 while the highest single-day reading hit 181 (Unhealthy). Metro residents averaged roughly 15.3 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 -5.5 points and the median AQI moved +3 points, which classifies the multi-year trajectory as worsening. 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 Canton-Massillon, OH (53.1% good, AQI 49); Carlsbad-Artesia, NM (53.7% good, AQI 49); Kingsville, TX (51.7% good, AQI 49).