- 2 Pa. metro areas have some of the highest air pollution in the U.S. PennLive.com
- Almost Half of Americans Breathe Unhealthy Air, Report Finds The New York Times
- Baltimore County gets “F” grade for ozone smog, according to pollution report CBS News
- The Bay Area and Detroit rank similarly on a very unfortunate list SFGATE
- Map Reveals 25 Most Polluted US Cities Newsweek