Insights: Boise City, ID metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 47 over 252 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 163 Good days (65%), 89 Moderate (35%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 62 while the highest single-day reading hit 97 (Moderate). Metro residents averaged roughly 19.4 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 -7 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 Ardmore, OK (65.3% good, AQI 47); Baltimore-Columbia-Towson, MD (62.2% good, AQI 47); Cheyenne, WY (69.8% good, AQI 47).