DENVER - The American Lung Association has mixed news about the air in Fort Collins.
The group says Fort Collins has the 22nd most polluted air in the country, however, the group also named Fort Collins to its list of Cleanest U.S. Cities for Short-term Particle Pollution.
The listings are in the 15th annual State of the Air report.
Fort Collins got an 'F' for high ozone days, but an 'A' for particle pollution over a 24-hour period.
Particle pollution is "a pollutant recently found to cause lung cancer, poor air quality remains a significant public health concern and a changing climate threatens to make it harder to protect human health," according to the Lung Association.
Ground level ozone is created by chemical reactions between oxides of nitrogen and volatile organic compounds in the presence of sunlight, according to the Environmental Protection Agency. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOC.
The American Lung Association said it creates its list using uses the most recent air pollution data, compiled by the EPA for the two most widespread types of pollution - ozone (smog) and particle pollution (PM 2.5, also known as soot).
-- Other Colorado cities on list
Along with Fort Collins, Colorado Springs and Pueblo/Canon City were listed under "Cleanest U.S. Cities for Short-term Particle Pollution."
Colorado Springs earned a 'D' for high ozone days, putting it in the top 100 for high ozone days in the 277 metropolitan areas listed. Pueblo/Canon City's data was incomplete, so it was not graded.
Grand Junction was listed as one of the Cleanest U.S. Cities for Ozone Air Pollution. It earned a 'D' for particle pollution.
Denver earned a 'D' for high ozone days and a 'B' for particle pollution.
See the Colorado report by county: http://www.stateoftheair.org/2014/states/colorado/