US Breathing Pollution
The American Lung Association warns that a growing number of US residents are living in areas with unhealthy air pollution. More than 46.2 million people live in an area with unhealthful year-round levels of particle pollution.
http://www.stateoftheair.org/2014/key-findings/year-round-particle-poll…
More than 13 percent of people in the United States live in an area with too many days with unhealthful levels of particle pollution.
http://www.stateoftheair.org/2015/key-findings/short-term-particle-poll…