Which U.S. cities have dirtiest and cleanest air?
Apr 27, 2011 . Most U.S. cities with the dirtiest air are getting cleaner but half of . All 25 cities with the worst ozone pollution improved their air quality from .
America's Most Polluted Cities - Forbes
Apr 27, 2012 . In fact, five California cities have the worst air quality of all major U.S. metropolitan areas, according to the American Lung Association. The ALA .
Philly: 10th Most Polluted City in the U.S. | Be Well Philly
Apr 25, 2012 . The report looks at ozone pollution (i.e. smog) as well as particle . assigns grades to determine the most and least polluted cities in America.
11 U.S. Cities With the Worst Air Pollution - Health.com
11 U.S. Cities With the Worst Air Pollution. The good news: Air has gotten cleaner in recent years. Now the bad: More than half of people in the U.S. still breathe .