Six in 10 Americans live in areas with unhealthy air pollution levels, according to the annual American Lung Association report released Wednesday.
The report ranks the healthiest and unhealthiest cities across the U.S., based on air quality measurements reported to the Environmental Protection Agency between 2005 and 2007.
The figures worsened, compared to last years report, showing that 186 million people were exposed to unhealthy air, up from 125 million.
Health effects from air pollution include changes in lung function, coughing, heart attacks, lung cancer and premature death.
However, some notoriously polluted cities, like Los Angeles, New York and Atlanta, have continued to improve air quality.
But only nine monitored cities nationwide were found to have ozone levels that did not register in the "unhealthful" range at some point during the year. Billings, Montana was the cleanest of those cities.
Cheyenne, Wyoming topped the list of cleanest cities for long-term particle pollution.
Check the top 25 lists for most-polluted and read more coverage at teh link below.
