Insights: Phoenix-Mesa-Scottsdale, AZ metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 86 over 366 measured days in 2024, which corresponds to a Moderate band and a Very Poor metro-wide health grade. The monitored-day split lands at 25 Good days (7%), 227 Moderate (62%), and 102 Unhealthy-for-Sensitive-Groups (28%). The 90th-percentile AQI finished at 122 while the highest single-day reading hit 337 (Hazardous). Metro residents averaged roughly 2.0 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by +18 and the median AQI moved -34 points, which classifies the multi-year trajectory as improving. The metro recorded 12 unhealthy-or-worse days combined, on those days the EPA recommends that sensitive groups limit prolonged outdoor exertion, and many schools and athletic programs adjust outdoor activity accordingly. Metros with comparable AQI profiles include Los Angeles-Long Beach-Anaheim, CA (10.1% good, AQI 80); Riverside-San Bernardino-Ontario, CA (7.1% good, AQI 97); Bakersfield, CA (20.8% good, AQI 72).