Air Quality and Health

Hartford Skyline and AQI Logo

Local air quality affects how we live and breathe. Like the weather, it can change from day to day or even hour to hour. A key tool in understanding the health effects associated with outdoor air quality is the Air Quality Index, or AQI. When AQI values are above 100, air quality is considered to be unhealthy.  The CT DEEP issues the AQI daily, to provide the citizens of Connecticut simple information on local air quality. More information on the AQI and health effects can be found on these following links:

Connecticut Daily Air Quality Index (AQI)
View the daily predicted air quality index values for various towns throughout the State.

Historical Ozone Data
View tables of daily maximum 8-hour ozone averages as well as peak 1-hour values dating back to 1998 for Connecticut monitors.

Air Quality Index (AQI) Health Effects
Learn what the AQI levels mean about possible health effects.

Air Quality Index – A Guide to Air Quality and your Health
(EPA Airnow)

Air Quality Guide for Particle Pollution
Harmful particle pollution is one of our nation’s most common air pollutants. Use the chart on the guide to help reduce your exposure and protect your health

National Air Quality (EPA Airnow)
View the national air quality predictions and measurements, as well as those for Connecticut, on the national EPA Airnow web site.

Air Pollutant Descriptions
The six "criteria" pollutants are listed and explained.

National Ambient Air Quality Standards (NAAQS)
The National Ambient Air Quality Standards for the six "criteria" pollutants are listed.

Indoor Air Quality
The Department of Public Health's Indoor Environmental Quality Unit provides information and services related to indoor air quality, among other indoor environmental issues.

Connecticut's Forecasted Unhealthy Ozone Days
View the list of the days forecasted to be unhealthy. Tracking and documenting these days is important for sources required to restrict their activities on forecasted unhealthy ozone days.

Subscribe to the Air Quality Information and Ozone Forecast Listservs

  • Subscribe to the Air Quality Information listserv to receive a daily ozone forecast between May 1 through September 30, and a daily PM2.5 forecast year round.
  • Subscribe to the Ozone Forecast listserv to receive a daily 8-hour ozone forecast that is disseminated to Connecticut’s Industrial and Electric Generating Units’ combustion sources from May 1 through September 30.


Content last updated May 2, 2024