Air Quality
Good
Active Contamination
1
Active Permits
2
Air quality in Middlesex County is rated good with a median AQI of 36 (178 days measured in 2025). 1 contamination site are tracked, all with completed or ongoing remediation.
Air Quality — Middlesex County (2025)i
AQSThe Air Quality Index measures how clean or polluted the air is on a given day. AQI is reported at the county level. A score of 0-50 is considered good; 51-100 is moderate; above 100 may be unhealthy for sensitive groups.
Median AQI
PM2.5 Daysi
49Ozone Daysi
121Industrial Monitoringi
Toxic Release Inventory (TRI)i
TRIWastewater & Stormwater Permits (NPDES)i
NPDESContamination Sitesi
Contaminated sites tracked by the EPA and state agencies. Superfund sites are the most seriously contaminated locations. Brownfields are former industrial properties being cleaned up for reuse. LUST sites have confirmed leaks from underground storage tanks.