Insights: Washington-Arlington-Alexandria, DC-VA-MD-WV metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 46 over 304 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 193 Good days (63%), 104 Moderate (34%), and 7 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 71 while the highest single-day reading hit 140 (USG). Metro residents averaged roughly 19.0 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -21 and the median AQI moved -1 points, which classifies the multi-year trajectory as improving. 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 Albany, GA (55.6% good, AQI 46); Asheville, NC (68.1% good, AQI 46); Cedar City, UT (70.0% good, AQI 46).