While the air in Pittsburgh is the cleanest it's ever been, the American Lung Association still ranks the city among the United States' most-polluted metropolises.
Pittsburgh is one of two metro areas outside of California to rank among the top 25 most polluted by ozone smog and by soot, formally called long- and short-term particle pollution, according to the American Lung Association's State of the Air 2013 report released today.
Pittsburgh was ranked 7th in short-term particle pollution, 8th in year-round particle pollution and 24th among the ozone-polluted, the lung association said.
But the quality of air has improved in each category since last year, as "the air quality in Pittsburgh, and nationwide, continues the long-term trend to much healthier air," the group said in a press release.
The number of "unhealthy air days" decreased from 20.7 from 26.3, according to the survey.
Lexi Belculfine: email@example.com or 412-263-1878. Twitter: @LexiBelc.