18 PA Counties Get 'F' Grade For Pollution, New Analysis Says

Climate change is making air pollution a growing threat in Pennsylvania, according to a new American Lung Association’s 2025 “State of the Air” report. The report found that after decades of progress, the air we breathe is getting dirtier in many parts of the country.

According to the report, eighteen Pennsylvania counties were given 'F' grades for pollution in at least one of two categories: high ozone and particle pollution. The report notes that data is only available for 35 out of 67 counties in Pennsylvania.

Counties receiving an "F" grade for high ozone days include: Bucks, Berks and Philadelphia.

Counties receiving an "F" grade for particle pollution include: Adams, Allegheny, Berks, Blair, Chester, Cumberland, Dauphin, Delaware, Lackawanna, Lancaster, Lebanon, Lehigh, Montgomery, Northampton, Philadelphia, Washington and York.

Additionally, the Pittsburgh metro area ranked 12th worst in the nation for annual particle pollution.

The number of people living in counties that earned an “F” grade for unhealthy spikes in fine particle pollution increased to 77.2 million, up 12.1 million people from last year’s report. This is the seventh straight year this deadly pollutant increased, according to the American Lung Association.

The report noted that after decades of progress in reducing the two major air pollutants, 156.1 million people — 46 percent of all Americans — are living in places that get failing grades for unhealthy levels of ground-level ozone pollution, or smog, and fine particle pollution, or soot. They are two of the most widespread and dangerous of pollutants.

“This is nearly 25 million more people breathing unhealthy air compared to last year’s report, and more than in any other ‘State of the Air’ report in the last ten years,” according to the report.

“Extreme heat, drought and wildfires are contributing to worsening levels of air pollution across much of the U.S., exposing a growing proportion of the population to ozone and particle pollution that put their health at risk.”

Ground-level ozone causes more breathing difficulties than any other single pollutant, according to the report. From 2021 through 2023, 37 percent of the population — about 125.2 million people — were exposed to unhealthy levels of ozone. That’s 24.6 million more people than reported in last year’s air-quality study.

Since 2000, the American Lung Association report has tracked the successes of the Clean Air Act, including reductions over time in emissions from transportation, power plants and manufacturing. However, climate change is making it harder to protect air quality and human health, the organization said.

For years, the worst air pollution problems were in western states, but the 2025 report found the geographic distribution of air pollution shifting back East. The year 2023 saw improved conditions along the West Coast, but also a deadly heat wave in Texas and an unprecedented blanket of smoke from wildfires in Canada that drove levels of ozone and particle pollution in dozens of central and eastern states higher than they have been in many years.

Both smog and soot can cause premature death and other serious health conditions, such as asthma attacks, heart attacks, strokes, preterm babies, impaired cognitive function later in life and lung cancer.

The report noted that the burden of living with unhealthy air is not shared equally and that communities of color are disproportionately exposed to air pollution and are more than likely living with one or more chronic health conditions that make them vulnerable.

People of color make up 41.2 percent of the U.S. population, but 50.2 percent of those living in a place with at least one failing grade on the air quality report card. Notably, Hispanic individuals are nearly three times as likely as white individuals to live in a community with three failing grades, the report said.