Parts of Milwaukee region get a failing grade on air pollution from the American Lung Association

The American Lung Association has given failing grades to Milwaukee, Ozaukee and Kenosha counties for a key measure of air pollution in its annual national report card on the state of air quality.

The poor marks for the three counties are for smog — a summer air pollutant that can reach levels that are unhealthy, even for healthy people and those working or exercising outdoors.

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Ozone, or smog, is created when heat and light interact with pollutants such as nitrogen oxides and volatile organic compounds, which come from factories, power plants and emissions from cars and trucks.

When levels rise, it can aggravate respiratory problems, especially for children who are active outdoors, adults engaged in moderate or strenuous activities and people with lung ailments such as asthma.

Also getting grades of "F" are Door, Manitowoc, Sheboygan, Walworth and Rock counties, with the scores based on the number of days that air monitors measure pollutants above certain levels from 2014 to 2016.

According to the Lung Association, the counties with the highest number of days when air quality failed to meet federal standards were: Kenosha, 28; Sheboygan, 25; and Milwaukee, 14.

Waukesha County earned a "C." Washington County does not have an air monitor so is not graded by the association. Racine County was also not graded because it has data from the required three years of air pollution history at a new monitoring site.

Other grades across the state: "C" for Brown, Fond du Lac and Outagamie; "B" for Marathon and Dane; and "D" for Kewaunee.

The Wisconsin Department of Natural Resources disagrees with the methodology of the association and says, for example, the group counts high ozone days more liberally than accepted government practice.

DNR spokesman Jim Dick also said in an email the group's annual report skews results so that some counties are "erroneously" getting poor marks when, in fact, they are meeting the current federal standard for ozone.

That national standard is in the process of becoming more stringent. The association is using the stricter measure before it has been fully implemented by the U.S. Environmental Protection Agency.

The EPA is moving to a measure of 70 parts per billion — down from 75 parts per billion. The change was first advanced during the Obama administration after a government scientific review panel concluded there was a negative health impact of ozone at lower levels.

The EPA is expected to decide soon whether certain regions, including southeastern Wisconsin, will be designated as either meeting — or violating — the new standard for ozone.

In a preliminary determination in December, the EPA found the region and some other counties along Lake Michigan would not be in compliance.

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Wisconsin officials have since challenged that conclusion and say it would meet the new requirements if it were not for pollutants that drift in from Illinois and Indiana.

Dona Wininsky of the Lung Association in Wisconsin said her group believes the EPA should find that southeastern Wisconsin is in violation of the new standards.

"It's people lungs," she said. "They don't care where the ozone is coming from."

Looking back at old report cards in Wisconsin, Janice E. Nolen, assistant vice president of national policy for the association, acknowledged, "There's been a lot of improvement."

The reasons: New cars on the road emit less pollutants; gasoline is cleaner; power plants have been required to installed more robust pollution controls; and utilities are shutting down old coal-fired plants in favor of natural gas or renewable sources.

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The region will also benefit from the recent shutdown of We Energies' power plant in Pleasant Prairie in Kenosha County.

Despite a downward pollution trend, 2016's warm spring and summer — it was the state's second-warmest year on record — drove up ozone levels at monitors along the Lake Michigan shoreline.

Also some good news: The association gave good marks for another measure known as particle pollution, also known as soot. Milwaukee, Ozaukee and Waukesha all earned an "A" and Kenosha a "B."

Other grades for soot across the state where there were measures: An "A" for Marathon and "B" for Brown, Outagamie, Dane, Rock and Sheboygan.

Soot is microscopic particles that can get into lungs and the bloodstream.

The DNR's Dick said particle pollution had fallen 30% in the past decade.