The American Lung Association (ALA) recently released State of the Air 2011, its annual report on air pollution and which cities have got the worst. In total, 18.5 million Americans live in regions with unhealthy levels of year-round particle pollution.

According to the ALA, 13,000 Americans a year are killed from particle pollution from power plants alone.

And for people in “at-risk” groups, like people who already have asthma, chronic lung disease, cardiovascular disease, or diabetes, the hazards of such pollution are even greater.