The quality of the air we breathe has improved over the last fifteen years, but there are still over 100 million Americans breathing smog or pollution every day, the American Lung Association says.
The ALA's State of the Air report breaks down air quality across the country.
The report shows the most polluted cities are in California, Utah, Texas and Pennsylvania, but Americans across the country are affected. The study shows four of out ten people live in counties with unhealthy levels of smog and soot.
Only a few counties in Michigan were tested, and most were given a 'C' grade, including Benzie and Manistee counties. Missaukee County was given a 'B.'
To see a full list of Michigan counties tested, click here.
And as for the cleanest cities in the country for ozone pollution? Ames-Boone, Iowa made the top of the list, followed by Bellingham, Washington and Bend-Prineville, Oregon.