Two Chicago-area counties received failing grades in the American Lung Association's annual State of the Air report.
Cook and Lake counties were both given an "F" for short-term particle pollution, a pollutant the association noted was recently determined to cause lung cancer, and DuPage and McHenry counties received "C" grades. Will County came in highest with a "B."
Grades are calculated based on the American Lung Association's analysis of ozone and short-term levels of particle pollution which calculates the average number of days of high-range air pollution levels.
In a list of the most polluted cities in the country, metropolitan Chicago ranked 20 in ozone pollution, and 14 for short-term particle pollution, worse rankings than last year. California towns made up the top five, with Los Angeles coming in at most-polluted.
"We must set stronger health standards for pollutants and clean up sources of pollution in Chicago to protect the health of our citizens,” Mike Kolleng, manager of the Healthy Air Campaign, said in a statement.
In all, 147 million people in the U.S. -- almost half the country -- are breathing in unhealthy air.
"We have seen that the Clean Air Act delivers significant health benefits,” Kolleng said. “However, the past 15 years have also confirmed that air pollution is a more serious threat to our health than we’d previously known and is further complicated by climate change.”
Polluted air can lead to more asthma, heart attacks and stroke. The American Lung Association says particle pollution can penetrate deep into the lungs and even into the bloodstream, leading to premature deaths as well as lung cancer..
The association called for the clean-up of power plants, strengthening outdated ozone standards, clean-up of new wood-burning devices such as new wood stoves, protecting the Clean Air Act and funding the work to provide healthy air.