Pittsburgh region's air quality gets an 'F'American Lung Association says Allegheny County only one outside California to get “F” grades for smog and short and long-term soot.American Lung Association says Allegheny County only one outside California to get “F” grades for smog and short and long-term soot.
Source: Pittsburgh region's air quality gets an 'F' (https://www.post-gazette.com/local/2019/04/24/Pittsburgh-regional-air-quality-gets-failing-grades-again/stories/201904230099)