DEEP: Attainment of the National Ambient Air Quality Standards

Attainment and Non-Attainment of the National Ambient Air Quality Standards in Connecticut

Attainment and Non-Attainment of the NAAQS in Connecticut  

The State of Connecticut is designated as both attainment and non-attainment with respect to the National Ambient Air Quality Standards (NAAQS) for the following six criteria air pollutants: particulate matter (<10 micrometers in diameter-PM10 or <  2.5 micrometers in diameter-PM2.5); sulfur dioxide (SO2); ozone (O3); nitrogen dioxide (NO2); carbon monoxide (CO); and lead (Pb).  The current designations are:

        Attainment: CO, NO2, Pb, SO2, PM2.5 and PM10

        Non-Attainment: Ozone

When a state has been designated as attainment for an air pollutant, all regions of the state are in compliance with all the standards (i.e., short term and long term; primary and secondary) for the particular pollutant. This is the case for NO2, CO, Pb2 and SO2.  In addition, in 2005, EPA approved an attainment designation for New Haven for PM 10.  The rest of the state was already classified as attainment for PM10.  In September of 2013  Southwestern Connecticut was designated in attainment for PM2.5 , the rest of the state was already designated attainment.

When a state has been designated as non-attainment for an air pollutant, one or more of the standards for the pollutant have been violated in one or more regions of the state.  The non-attainment designation that is subsequently applied to a region can reflect the "degree" of non-attainment depending upon a number of factors including the air pollution history in the region, previous designation of the region as either attainment or non-attainment, lack of air pollutant monitoring in the region, and inferences made based on pollutant monitoring done in adjacent or similar regions.

For more information on the non-attainment pollutant, please visit the Ozone web pages.  To view a map for the Connecticut nonattainment areas, use the link below:

8-hour Ozone Non-attainment Map (PDF)   

Content Last Updated May 26, 2016