DES MOINES — The American Lung Association’s annual “State of the Air” report finds positive trends in air quality in two Iowa metros.

“Des Moines is actually listed on the ‘cleanest cities’ list,” said Kristina Hamilton, director of advocacy for American Lung Association of Iowa. “It’s ranked 154th in the nation.”

The Quad Cities saw “slight improvements” in the three types of pollution evaluated in the American Lung Association’s report. Overall results for Iowa were “largely positive,” according to Hamilton.

“I would like to note that we don’t have air quality monitors in every counties in Iowa,” Hamilton said. “Only a select few counties have air quality monitors.”

Sixteen counties of Iowa’s 99 counties have air quality monitors and the Lung Association was able to evaluate data from Bremer, Clinton, Hamilton, Linn, Montgomery, Palo Alto, Polk, Scott and Van Buren Counties.

The Lung Association’s report considers particle pollution, sometimes called soot, as well as ozone or smog and Hamilton said metro Des Moines is considered one of the country’s cleanest cities because it had fewer days with smog last year.

“For short term particle pollution we slightly more high particle pollution days in the Des Moines metro area, but it still ranked 79th, which was a better ranking than last year,” Hamilton said. “For annual particle pollution, we saw the same levels from the previous report, but a better ranking.”

Exposure to air pollution over a long period of time can cause or inflame lung conditions like asthma and C-O-P-D — chronic obstructive pulmonary disease. This is the 25th year the American Lung Association has issued its “State of the Air” report.