Insights: Santa Cruz County, Arizona. EPA monitors recorded a median Air Quality Index of 49 across 364 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 190 (52%) fell in the Good band (AQI 0–50), 171 (47%) registered Moderate readings, and 2 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 73, while the worst single-day peak hit 187 (Unhealthy). Residents averaged about 15.7 clean-air days per 30-day window during the monitoring year.

The full pollutant mix ranks as PM2.5 (289 days), PM10 (75 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -5.6 points and the median AQI moved +5 points, placing the multi-year trajectory at worsening. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Apache (86.2% good, AQI 33); Cochise (69.9% good, AQI 45); Coconino (70.1% good, AQI 46); Gila (62.7% good, AQI 47); La Paz (76.6% good, AQI 44); Maricopa (8.8% good, AQI 73).