Four Wisconsin counties north of Milwaukee have ozone levels that exceed new federal regulations, the Environmental Protection Agency has declared.

Door, Kewaunee, Manitowoc and Sheboygan counties — all eastern counties on Lake Michigan's shore — have failed to meet the EPA's newest clean air standards, the EPA announced last week.

The four counties' levels of ozone pollution have not significantly increased, according to Doug Aburano, EPA environmental engineer. New clean air standards have reclassified them as having unsafe levels of ozone pollution.

The four newly reclassified counties will be added to a list of counties nationwide that do not have sufficiently clean air as soon as an update to that list is published in a few weeks, Aburano said.

The greater Milwaukee counties — Ozaukee, Washington, Waukesha, Racine, Kenosha and Milwaukee — have been on the list since 1991.

Door, Kewaunee, Manitowoc and Sheboygan counties have had previous problems with ozone pollution, Aburano said.

"All of these areas have not met ozone standards before," Aburano said. The four newly reclassified counties were initially on the national list of counties with polluted air. They were dropped but are now being re-added because of new clean air standards that were adopted in 2004, according to Aburano.

Door, Kewaunee and Manitowoc counties are classified as "basic nonattainment areas" by the EPA, meaning their pollution levels are only slightly above federal limits. Because of the classification, the three counties will have to enroll in two air pollution control programs, Aburano said.

The first program, the New Source Review, mandates that a constant level of pollution be kept in a nonattainment area. The equilibrium can be achieved, Aburano said, by installing new, cleaner equipment or by asking other polluters in the area to cut their own emissions.

The second program, Conformity, demands that any new transportation projects, such as new highways or bridges, conform to an emissions budget and not create a decrease in air quality.

Sheboygan County, however, is more polluted than the other three newly reclassified counties and so is classified as a "moderate" area. Because of this classification, Sheboygan must enroll in an additional program.

"The Conformity and New Source Review are the bare minimum," Aburano said. "For moderate areas, you have to decrease pollution from existing sources."

The additional program that Sheboygan must now enroll in, called the Reasonably Available Control Technology Plan, takes aim at major contributors of ozone-causing pollutants and forces them to curb their emissions.

"Instead of looking at modifying new (polluters), we're looking at the ones that are already there," Aburano said.

The programs will be overseen by the Wisconsin Department of Natural Resources with supervision from the federal EPA, according to Aburano.

The four newly classified counties are the apparent victims of what is called the transport phenomenon, Aburano said. None of the counties is beset with particularly troubling concentrations of ozone-causing polluters, but suffer from ozone pollution nonetheless because of wind patterns, which sweep ozone and its formative components in their direction.

"Winds will take ozone up the shore of Lake Michigan," Aburano said.

The winds take ozone and its precursors from Gary, Ind., Chicago and Milwaukee and deposit them on the four reclassified counties, he said. The same phenomenon occurs on Lake Michigan's easternmost shore.

William Brower, professor of mechanical and industrial engineering, agreed.

"It has nothing to do with who lives where — it's where the source of effluent is," he said.

The idea that ozone — the main component in the urban haze widely known as smog — is directly caused by cars is a misconception, Aburano said.

"Ozone is not directly emitted from anything," Aburano said.

Rather, ozone is caused by mixing volatile organic compounds, such as inks, fuels and paints, with nitrogen oxides — referred to by scientists as NOX for their chemical abbreviation — at temperatures above 80 degrees, Aburano said. Common sources for these ozone ingredients include cars, power plants, refineries and factories.

The result of such a mixing is ozone, a bluish gas that can inflame and damage the cells that line the lungs, irritate air passages, reduce lung function and aggravate asthma, according to the EPA. It also may aggravate chronic lung diseases like emphysema and reduce the immune system's ability to combat bacterial infections.

The type of ozone created by pollutants, called ground-level ozone for its tendency to remain close to the earth's surface, is not the same as the ozone in the Earth's atmosphere, which is beneficial because it shields the Earth from harmful ultraviolet radiation. Ground-level ozone is especially problematic in the summer months when abundant sunshine and warm days are conducive to ozone formation, the EPA claims.