Report Giving Pittsburgh Air A Failing Grade Doesn't Tell The Whole Story, Researchers Say

May 1, 2019

Pittsburgh’s air quality made headlines last week when the American Lung Association released its annual report: the region was listed among the top 10 most polluted cities in the country.

The report covers a large geographic area outside of Pittsburgh, from Butler County, into Ohio and West Virginia through Westmoreland and Fayette counties. Because air quality can vary drastically from one location to another, some researchers say this report is somewhat misleading.

“It’s a challenge because air quality is not constant everywhere,” said Carnegie Mellon University mechanical engineering professor Allen Robinson. “Certainly around highways and industrial facilities air quality can be much worse, and so you get these hot spots … and it’s really hard if you’re measuring in a hot spot then assigning it to this broader area, it could be not representative.”

One of those hot spots is U.S. Steel’s Clairton Coke Works. The Allegheny County Health Department has an air quality monitor in Liberty Borough, just downwind of the facility. Robinson said this data can skew the picture of regional air quality as a whole.

According to the health department, the levels of fine particulate matter captured at the Liberty monitor were in compliance with the Clean Air Act for the first time in 2018, though it’s unclear how emissions after a Christmas Eve fire at the plant might affect 2019 pollution levels.  Over the last 20 years, said Robinson, air pollution levels in Pittsburgh have been cut almost in half, due in part to cleaner cars and stricter controls on power plants and other industrial polluters.

“Nationally, 100,000 lives are saved each year associated with the cleaner air,” Robinson said. “So that’s a real benefit.”

Robinson and other CMU researchers are working to build a more nuanced picture of air quality in Pittsburgh, by using sensors on vehicles and deploying sensors to different neighborhoods around the city.

“One of the things that we found is levels near freeways are not as high as you might think,” Robinson said. “But in terms of other sources, certainly like the South Side, actually the pollution levels are pretty high and that’s because there’s a lot of restaurants … there.”

Hyper-local air quality data is available via the Breathe Project, and CMU’s Center for Atmospheric Particle Studies just rolled out a new real-time map that gets updated every 15 minutes.