Fairfield, Connecticut, is among the 25 most polluted counties in the U.S. for ozone pollution, according to the annual State of the Air report from the American Lung Association.
Ruth Canovi, the association’s director of advocacy in Connecticut, said year after year, Fairfield County used to have the worst ozone pollution east of the Mississippi.
“This year, actually, there was one metro area that has worse worsening ozone than we do,” she said. “But that's not because we've improved. That's because they worsened.”
Cook County, Illinois, is now at the top of this unfortunate list.
“Fairfield County has certainly the worst ozone pollution, or smog pollution, in all of New England,” Canovi said.
Ozone smog and daily particle pollution worsened in the New Haven, Hartford and the Waterbury metro area, according to the report. Unhealthy days for short-term particle pollution more than tripled in Litchfield County.
“Both ozone pollution and particulate matter pollution … they're two of the most widespread and dangerous air pollutants,” Canovi said. “They can cause asthma attacks, respiratory and cardiovascular harm, including heart attack and stroke and even early death.”
Even relatively low levels of ozone can cause health effects, according to the U.S. Environmental Protection Agency.

Fairfield County accounts for about 25% of Connecticut's population.. Compared to the rest of Connecticut, according to the report, the county had the most pediatric asthma cases (15,463); adult asthma (81,758); chronic obstructive pulmonary disease (35,190); lung cancer (537); and cardiovascular diseases (56,117).
‘The air quality has gotten worse’
Across Connecticut, people working in outdoor jobs, like construction and landscaping, and unhoused populations and those living close to highways and industrial sites continue to be disproportionately impacted, said Dr. David Hill, a pulmonary and critical care physician at Waterbury Hospital.
“The air quality has gotten worse and more patients are coming in with increased trouble breathing on hot and humid days, when the air quality is worse,” he said.
Hill recalled higher patient volumes and new onset asthma during the Canadian wildfires in 2023, and is concerned by the current wildfires in New Jersey.
More than 125 million people live in U.S. counties with “F” grades for ozone smog. And 93 additional counties earned an “F” in this year’s report (2021-2023 data), according to the American Lung Association, which has published its annual air quality data since 2000.
This annual “report card” tracks exposure nationwide to unhealthy levels of ozone and particle pollution. The latest data showed that 77 million people in the U.S. – more than one-fifth of the nation’s total population – live in counties with “F” grades for particle pollution.
Climate change to blame
Canovi said climate change takes much of the blame.
“The Clean Air Act was passed in the 1970s, and the air has gotten better,” she said. “However, we know that climate change is making it harder for us to clean up the air, so we really need to do all that we can to reduce emissions from fossil fuel sources.”
Canovi urged people to pay attention to air quality. “We want them to take precautions when they know their health is at risk,” she said.
Tools to use
The AirNow Web site provides daily air quality reports for many areas. These reports use the Air Quality Index (or AQI) to tell you how clean or polluted the air is.
EnviroFlash, a free service, can alert you via email when your local air quality is a concern. Sign up at www.enviroflash.info.