Pollution in the Chicago metropolitan area increased "significantly" between 2014 and 2016, according to the American Lung Association’s 19th annual "State of the Air" study, which was released late Tuesday.

"State of the Air" analyzed ozone particle pollution both short-term and over the course of the year to determine cities’ air quality over a three-year period using data from the Environmental Protection Agency.

Chicago received an “F” in ozone, or smog, pollution and advanced from the 26th most ozone-polluted city in the 2017 report to the 22nd most in Wednesday's edition. The city was not included in the year-round or short-term particle pollution studies due to a lack of data, according to a statement from the American Lung Association.

The city saw 28 days with unhealthy levels of ozone pollution in the 2018 study, an increase of 10 days over the previous study, the release said.

Los Angeles suffered from the most ozone pollution, with about 150 days at unhealthy levels, according to the report. More than 50 cities tied for the least ozone pollution with zero days at unhealthy levels, including two Illinois cities: Decatur and Quincy.

There was a nationwide spike in ozone pollution that exposed approximately 9 million more people to unhealthy levels of pollution, according to the Lung Association, but year-round and short-term particle pollution trended downward and an overall increase in air quality.

Still, 41 percent of the nation lives in high levels of pollution, putting them at risk of asthma, lung cancer, shortness of breath, premature death and more, the association said.

“We can and should do more to save lives,” Angela Tin, vice president of clean air for the American Lung Association's upper Midwest branch, said in a statement.

“The Lung Association calls on our members of Congress to defend the Clean Air Act, currently under threat from those who want to weaken this effective public health law," Tin's statement continued. "We also call on the U.S. Environmental Protection Agency to implement and enforce the law instead of trying to roll back major safeguards like the Clean Power Plan and cleaner cars, both steps that help us fight climate change and reduce air pollution.”

To view the full report, click here.

Chicago earlier this year was ranked the fourth-dirtiest city in the U.S. by the cleaning service BusyBee based on litter, air quality, pests and population density.