Philadelphia Metro Area Continues to Rank Among Worst 25 in Nation for Ozone and Year-round Particle Pollution

climateImage by Gerd Altmann
American Lung Association's annual air quality report finds over 40% of Americans breathing unhealthy air

PHILADELPHIA, PA —This year’s “State of the Air” report from the American Lung Association finds that the 16-county Philadelphia-Reading-Camden, PA-NJ-DE-MD metro area ranked as the nation’s 17th most polluted city in the nation for its year-round average levels of fine particle pollution and as the 21st most polluted for days with high levels of ozone smog. The area showed a worsening of its worst measure for short-term particle pollution, with its rank falling from 48th to 39th worst in the country. See the full report, based on the three years of data from 2017 through 2019, at

The worst grades in the metro area for the daily pollution measures remain concerning, with particle pollution worsening to a “D” (in Berks County) and ozone smog improving, but still earning an “F” (for the area’s worst results in Philadelphia County). “Clearly, more must be done to protect the health of people at risk,” said American Lung Association Director of Environmental Health Kevin Stewart. “There are dozens of days when the air pollution levels are high enough to harm health and trigger asthma attacks, heart attacks and stroke, placing children, older adults, and people living with chronic lung and heart disease at particular risk. Ozone and particle pollution are the nation’s most harmful and widespread air pollutants, and both can be deadly. In addition, more exposure to particle pollution is linked to worse health outcomes from COVID-19, including more deaths.”

“The American Lung Association’s 2021 ‘State of the Air’ report shows that despite some nationwide progress on cleaning up air pollution, more than 40% of Americans live with unhealthy ozone or particle pollution,” said Stewart. “People of color are significantly more likely to breathe polluted air than white people. As the nation works to address climate change and continue reducing air pollution, we must prioritize the health of disproportionately burdened communities.”

Ozone Pollution in Philadelphia-Reading-Camden metro area – Compared to the 2020 report, the Philadelphia metro area experienced fewer unhealthy days of high ozone as Philadelphia County displaced Bucks County as worst county in the metro area for this measure. Philadelphia posted 9.8 unhealthy ozone days on average in 2017-2019, a serious “F” grade, but still a clear improvement over Bucks County’s 11.5 days in last year’s report covering the years 2016-2018. Due to improvements elsewhere in the country, the area’s ranking worsened to 21st most polluted in the country from 23rd worst in last year’s report.

“Ozone pollution can harm even healthy people, but is particularly dangerous for children, older adults and people with lung diseases such as COPD or asthma,” said Stewart. “Breathing ozone-polluted air can trigger asthma attacks in both adults and children with asthma, which can land them in the doctor’s office or the emergency room. Ozone can even shorten people’s lives.”

Particle Pollution in Philadelphia-Reading-Camden metro area “State of the Air” 2021 found that the worst year-round particle pollution levels in the Philadelphia metro area remained the same as in last year’s report. Though it met the standard for year-round fine particle pollution for the fifth year in a row, the metro area continued to rank among the nation’s worst cities for this pollutant—even as its rank improved from 12th worst in last year’s report to 17th worst. Delaware County remained the county with the highest annual average in the metro area, only slightly worse than the area’s best ever performance.

The report also tracked short-term spikes in particle pollution, which can be extremely dangerous and even lethal. After three years of improvement to its best performance ever, the metro area posted a significantly worse average number of days for fine particle pollution in 2017-2019. Berks County was the most polluted county in the metro area, with a weighted average of 2.5 days (a “D” grade) with unhealthy air quality during 2017-2019. Berks County and Camden County, NJ had been tied for worst in last year’s report, with a weighted average of 1.3 days (a “C”).

“Particle pollution can lodge deep in the lungs and can even enter the bloodstream. It can trigger asthma attacks, heart attacks and strokes and cause lung cancer,” said Stewart. Particle pollution comes from industry, coal-fired power plants, construction, agriculture, vehicles, wildfires and wood-burning devices.”

The year’s report found that nationwide, more than four in 10 people (135 million) lived with polluted air, placing their health and lives at risk. In the Philadelphia metro area, air pollution placed the health of more than seven million residents at risk, including those who are more vulnerable to the effects of air pollution, such as older adults, children and people with a lung disease. The report also shows that people of color were 61% more likely to live in a county with unhealthy air than white people, and three times more likely to live in a county that failed all three air quality grades. The report also finds that climate change made air quality worse and harder to clean up.

“The burdens of unhealthy air fall heaviest on our children, seniors, lower income communities and residents with existing heart and lung disease. These challenges are only compounded by the increasing well-documented and understood public health threats associated with climate change driven by fossil fuels,” said Stewart.  “Our changing climate demands urgent action to reduce impacts to public health, air quality and our quality of life. Therefore, tightening the cap on harmful carbon emissions within the overall drive to reduce carbon pollution from all sectors is a proactive step that Pennsylvania can take by joining the Regional Greenhouse Gas Initiative (RGGI). The regional efforts to reduce power plant emissions are an important step toward securing critical emission reductions.”

The Lung Association’s annual air quality “report card” tracks and grades Americans’ exposure to unhealthful levels of particle pollution (also known as soot) and ozone (smog) over a three-year period—this year’s report covers 2017-2019. The report analyzes particle pollution in two ways: average annual levels and short-term spikes. Both ozone and particle pollution can cause premature death and other serious health effects such as asthma attacks and cardiovascular damage, and are linked to developmental and reproductive harm. Particle pollution can also cause lung cancer.

Learn more about “State of the Air” at and sign the petition for the Biden Administration to promote clean air, a safe climate and environmental justice.

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