2022 CEQ Annual Report

Air Quality

Climate Changers Air Pollutants

Air Days

Quick Summary - x check dash

Connecticut residents breathed healthful air on 341 days in 2022; an increase from the ten-year average (340 days).

The number of statewide “good air days” decreased from 342 in 2021 to 341 days in 2022. A “good air day” is when every monitoring station in the state records “satisfactory air quality”, which is defined here as air that meets the health-based National Ambient Air Quality Standard (NAAQS) for all of the following six pollutants: sulfur dioxide, carbon monoxide, particulate matter (PM2.5 and PM10), nitrogen dioxide, and ground-level ozone.*

Air with an Air Quality Index (AQI) above 100 is considered “unhealthy for sensitive groups”, which includes people with heart or lung disease, older adults, and children. In 2022, there were 23 days that exceeded the AQI for ozone as the primary pollutant and one day that exceeded the AQI for particulate matter (PM 2.5) as the primary pollutant. Exposure to particle pollution is linked to a variety of significant health problems, ranging from aggravated asthma to premature death in people with heart and lung disease. Fine particles are a health concern because fine particles can easily reach the deepest parts of the lungs.⁸

In 2022, the Department of Energy and Environmental Protection (DEEP) issued a special report which noted that “Connecticut has again failed to meet both the 2008 and 2015 National Ambient Air Quality Standards (NAAQS) for ozone within the timeframe prescribed by EPA. Resultantly, DEEP expects EPA to begin the process necessary to reclassify Fairfield, New Haven and Middlesex Counties to “severe” nonattainment under the 2008 ozone NAAQS. This means DEEP will be required to amend its clean air regulations and identify additional strategies to reduce emissions.”⁹

There has been a long term trend of improved air quality, in part, due to the air pollution controls that were put in place after the 1971 Clean Air Act. The chart below, “Air Pollutants”, shows that in the 1980’s, exceedances for sulfur dioxide (SO2) and nitrogen dioxide (NO2) were common, but not so recently.¹⁰ Statewide exceedances of pollutants, except for ozone, are rarely seen, due to federal restrictions on emitters, mostly to Connecticut’s west and southwest. Lead (Pb) is not shown.**

Air Pollutants

The image (below) illustrates a bad-air day in 2022 that was more intense than average but followed the typical pattern of Connecticut having the worst ozone pollution in New England.¹¹ The yellow areas indicate moderate air quality, but it meets the standard for ground-level ozone, while the orange and red areas did not. Some residents in the yellow areas, who are unusually sensitive to air pollution, might have been adversely affected. Much of Connecticut's ground-level ozone Area of southern New England that depicts a bad-air day in 2022 originates in states to the west and southwest. Unless emissions in those states are reduced substantially, Connecticut residents are likely to continue to breathe unhealthful air. Past ozone control strategies for nitrogen oxides (NOx) have centered around point source electrical generating units, which have been effective in reducing long-range air pollutant transport into Connecticut. Increasingly, area sources and on-road / non-road mobile sources have become the dominant source of NOx production.¹²

Cities and towns in coastal regions of the state usually see more bad ozone days than inland locations. Coastal towns with monitoring stations that saw the most unhealthful days in 2022, included Westport (14), Greenwich (12), and Stratford (10); while the air monitoring stations in Abington (Pomfret)(0), Stafford (2), and Cornwall (3), saw the fewest.¹³

No other New England state had more days with unhealthful levels of ozone than Connecticut, which had a total of 23 in 2022. Rhode Island was the next highest with five unhealthful days due to ozone.¹⁴

_Goal:_{While not formally stated, the goal is for Connecticut residents to have a “good air day”, every day.}

_{Technical Note:}_{*The federal air quality standard for ozone was revised prior to the 2016 ozone season. The new standard (0.070 parts per million over eight hours) is slightly more protective of human health than the older standard (0.075). **Connecticut’s lead levels have been below the national standard (NAAQS) since 1994.}

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⁷_{EPA, Air Data: Air Quality Data Collected at Outdoor Monitors Across the US; www.epa.gov/outdoor-air-quality-data.}⁸_{Connecticut Department of Health (DPH), Air Pollution; portal.ct.gov/DPH/Environmental-Health/Environmental-and-Occupational-Health-Assessment/Air-Pollution.}⁹_{DEEP, An Assessment of Connecticut’s Need to Adopt California’s Medium and Heavy-Duty Vehicle Emission Standards, p. 8, March 2022; portal.ct.gov/-/media/DEEP/air/mobile/MHD/MHD_Whitepaper_030822.pdf.}¹⁰_{EPA, Outdoor Air Quality Data, Air Data – Multiyear Tile Plot, accessed 1-3-2023; www.epa.gov/outdoor-air-quality-data/air-data-multiyear-tile-plot.}¹¹_{EPA, AirNow, Interactive Map of Air Quality, Archive – August 5, 2022; gispub.epa.gov/airnow/index.html?tab=3&contours=ozone.}¹²_{DEEP, Source Contribution to Connecticut’s Ozone Problem; portal.ct.gov/deep/air/planning/ozone/source-contribution-to-connecticut-ozone.}¹³_{DEEP, Annual Summary Information for Ozone; portal.ct.gov/DEEP/Air/Monitoring/Annual-Summary-Information-for-Ozone.}¹⁴_{EPA, Historical Exceedance Days in New England; www3.epa.gov/region1/airquality/standard.html.}

Connecticut State Council on Environmental Quality