Half of all Americans breathe polluted air
The United States has made progress in cleaning up air pollution, but 154.5 million people, about half the population, live where the air is so polluted with smog and particles that it is often dangerous to breathe, according to the State of the Air 2011 report. Nearly half the people in the United States, 48.2 percent, live in counties that received an "F" for air quality due to unhealthy ozone levels. Los Angeles-Long Beach-Riverside, California remains the metropolitan area with the worst ozone problem, although great improvements have been made since the report was first issued 12 years ago. In fact, eight of the 10 most ozone-polluted cities are in California, the report shows. Honolulu, Hawaii and Santa Fe-Espanola, New Mexico are identified as the cleanest cities – the only two cities in the nation that were among the cleanest for year-round particle pollution and also had no days when ozone and daily particle pollution levels reached unhealthy ranges.
Source: American Lung Association, 27 April 2011