Mo' People, Mo' Problems. 

If you feel like healthy breathing has disappeared into thin air, you're not wrong, according to the American Lung Association. 

Its most recent State of the Air report finds that Denver has fallen two points from the last ranking cycle to land at the 12th worst city for air quality. It was given a "D" grade for both high ozone days and particle pollution. Denver finished only two spots better than New York. 

“Denver residents should be aware that we’re breathing unhealthy air, placing our health and lives at risk,” said American Lung Association director of advocacy JoAnna Strother.

The culprit, the association says, is ozone pollution, which is visible to us every time that hideous brown-cloud ring envelops the skyline on a fairly regular basis. Denver experienced more days of high ozone this year than in 2018. The biggest cause of this type of pollution is an increased amount of cars on the road due to population growth. Denver has reportedly grown by nearly 20 percent since 2010, and surrounding cities and counties are growing at high rates, as well. 

“Ozone especially harms children, older adults and those with asthma and other lung diseases,” said Strother. “When older adults or children with asthma breathe ozone-polluted air, too often they end up in the doctor’s office, the hospital or the emergency room. Ozone can even shorten life itself.” 

The cities that ranked as having worse air pollution than Denver in terms of ozone are (in order, 1-11) Los Angeles, Visalia (CA), Bakersfield, Fresno area, Sacramento, San Diego, Pheonix, San Francisco area, Houston, New York, and Redding (CA). 

The top five cleanest cities in terms of ozone are Anchorage, Bangor (ME), Bellingham (WA), Bowling Green area (KY), and Brownsville area (TX). 

If you are at risk when air quality is less than optimal (or you just want to breathe as cleanly as possible), please check out American Lung Association's 10 tips for protecting yourself from unhealthy air. You can also view the full report and see the pollution breakdown of Colorado's cities and counties on the association's website. 

What do you think of Denver's results? Let us know your thoughts in the comments below.