But the numbers are improving.
More than half of Americans live in places where the air is unhealthy, according to a new report from the American Lung Association.
Pennsylvania cities are high on the list of places with the worst air pollution.
The report found that the Pittsburgh metro region has the 8th highest levels of year-round particle pollution — also known as soot — in the country. The Harrisburg area ranked 9th, the Philadelphia area was 12th, Altoona was 14th and Lancaster was 16th.
This kind of pollution can cause swollen lungs, asthma attacks, shortness of breath, coughing, and even premature death, says Paul Billings, Senior Vice President for Advocacy at the American Lung Association.
The report tracked another pollutant: ozone, also known as smog.
Smog is not only a problem for cities, Billings says. “We traditionally thought of ozone as an urban problem, but what we often find is that communities that are downwind of a major city have some of the highest ozone levels in the eastern part of the United States.”
But there is some good news: air pollution levels in many Pennsylvania cities have been decreasing.
Billings says that’s in large part because of the Clean Air Act, a 1970 federal law that regulates air emissions. “The steps that have been taken over the last 45 years to reduce emissions are paying dividends,” Billings said. “So the air in Philadelphia is much cleaner than it was decades ago.”
But, he said, “we still have a ways to go until we get air that is truly safe and healthy to breathe.”
The report calls for emissions reductions and stronger limits on air pollution that blows across state lines.