The air we breathe is getting cleaner, but not by much.

The latest clean air report from the American Lung Association gave Dane County a 'C' for ozone, an improvement over the 'F' received in the previous study, but fine particle pollution gets an 'F', the same grade from the last study.

The study, "State of the Air 2010," was released on Wednesday.

Lisa MacKinnon, coordinator for the Dane County Clean Air Coalition, said in a news release that the new grades reflect the efforts the coalition has made in trying to cut down on pollution.

"While these grades don't put Dane County at the top of the class for clean air, Dane County's air quality has been improving over the last few years and currently meets state and federal standards," MacKinnon said.

The 2010 report is based on data collected from 2006-2008. The data showed Dane County had five high ozone days per year and 12 high particle pollution days per year.

The 2009 report, based on 2005-2007 data, said the county had 10 high ozone and 14 high particle pollution days per year.

MacKinnon said more stringent measures are coming from the U.S. Environmental Protection Agency.

"We all need to step up our actions for healthier air," MacKinnon said. "2010 will be a critical year for Dane County because the EPA is getting ready to create even more strict public health standards for both ozone and fine particle pollution."

The Los Angeles area had the nation's worst ozone pollution, according to the study, as reported by the Associated Press on Wednesday.

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Bakersfield, Calif., had the worst short-term particle pollution, and the Phoenix-Mesa-Scottsdale area of Arizona had the worst year-round particle pollution.

The U.S. cities with the cleanest air were Fargo, N.D.; Wahpeton, N.D.; and Lincoln, Neb.

For more on the state of Wisconsin's air, go here.