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Air Quality Index

The U. S. Environmental Protection Agency (EPA) has provided a scale called the Air Quality Index (AQI) for rating air quality. This scale is based on the National Ambient Air Quality Standards (NAAQS). The AQI forecast is updated once daily, excluding weekends and holidays. Alternatively, you may call the Air Quality Index Hotline at (800) 249-1234 or (860) 424-4167 for the forecast or link to Airnow.gov for the most current air quality information.

Current air quality is provided below the AQI forecast section.

Current Air Quality

Air Quality for Wednesday, 12/17/25

Good to Moderate
AQI Scale

For current conditions, see map below.

Cautionary Statements

AQI Forecast

Forecast for Wednesday, 12/17/25

Moderate

Forecast for Thursday, 12/18/25

Good to Moderate

For local forecasts, see table below.

Restrictions For Regulated Community

Ozone forecasting has come to a close. Ozone concentrations from October through April are expected to remain in the GOOD, to occasionally MODERATE range.

For details, see operating restrictions page.

Historical Ozone Data
Forecasted Ozone Exceedance Days
Tips for Ozone Action Days
Air Monitoring in Connecticut

AIRNOW Interactive Map of Air Quality

Local AQI Forecast

Town Wednesday, 12/17/25
FineParticles (PM2.5)		 Wednesday, 12/17/25
Ozone (O3)		 Thursday, 12/18/25
FineParticles (PM2.5)		 Thursday, 12/18/25
Ozone (O3)
Bridgeport 61 63
Danbury 60 61
Greenwich 61 63
Hartford 61 58
Madison 54 50
Middletown 61 58
New Haven 58 54
New London-Groton 54 50
Stafford 56 50
Stratford 61 63
Torrington 56 50
Waterbury 60 60
Westport 61 63
If you have any questions regarding the Air Quality Forecast, please contact the Bureau of Air Management by phone at (860) 424-4152 or by email.