Countdown The 25 Most Dangerously Polluted Cities In The US

29Polluted Cities Countdown

More than 125 million Americans live in areas with unhealthy levels of air pollution, according to the American Lung Association’s 2017 “State of the Air” report. Polluted cities are a major problem today.

Pollution leads to various kinds of nasty health outcomes, including asthma, lung cancer, and shortened lifespans.

The report, released April 19, rounds up air quality data regarding 2013, 2014, and 2015 in the United States.( Because air quality data is plentiful and complicated, the annual ALA reports usually seem two years into the past .)

The report focuses on two key kinds of pollution: particles and ozone.

Particles include everything from dust kicked up during a drought to tiny particles floating in the air from forest flames or fossil fuels. Ozone, or smog, develops in the upper atmosphere when emissions from tailpipes and smokestacks cook in the sun’s heat.

Local pollution levels can be measured according to totals of ozone in the atmosphere, number of days with extremely high particle pollution levels, or high levels of year-round particle pollution. Those metrics yield different outcomes with Los Angeles being the worst US city for ozone. But Los Angeles is not necessarily #1 in all categories like year-round particle pollution.

Janice Nolen, the lead writer of the ALA report, told Business Insider that local problems like automobile traffic can build a particular cities ozone or particle problems more quickly, but that the overall issue is a national one. Even a place with strong environmental regulations can be vulnerable to bad air flowing in from other parts of the country.

Here are the US cities with the worst year-round particle pollution. (The report notes, however, that data is missing on all of Illinois, most of Tennessee, and part of Maine.) For more information and suggested policy solutions, you can read the full report.