Insights: Trenton, NJ metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 43 over 235 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 173 Good days (74%), 57 Moderate (24%), and 5 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 66 while the highest single-day reading hit 122 (USG). Metro residents averaged roughly 22.1 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -89 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 Allentown-Bethlehem-Easton, PA-NJ (65.6% good, AQI 43); Amarillo, TX (75.7% good, AQI 43); Ashtabula, OH (81.2% good, AQI 43).