AQI 50 · PM2.5 · Trend: Improving
| Average AQI | 50 |
| Good Days / Year | 210 |
| Unhealthy Days / Year | 10 |
| Primary Pollutant | PM2.5 |
| PM2.5 Average | 9 µg/m³ |
| Trend | ↓ Improving |
| Monitoring Stations | 8 |
| Nonattainment Areas | 1 |
Delaware's small size means it is significantly affected by regional pollution from the Philadelphia-Baltimore industrial corridor. The state's chemical industry heritage has left both cleanup challenges and strong environmental monitoring.
DNREC (Dept. of Natural Resources and Environmental Control) manages air quality. Member of RGGI. Strong chemical industry emission controls.
New Castle County — ozone and PM2.5 nonattainment. Located in the Philadelphia-Wilmington industrial corridor.