Ozone Pollution

Several counties in eastern Wisconsin are considered non-attainment areas for ozone air pollution. On October 1, 2015, the United States Environmental Protection Agency defined the ozone standard to be 70 parts per billion over an 8-hour period. According to the September 2017 EPA’s list of Current Nonattainment Counties for All Criteria Pollutants, Sheboygan and Kenosha Counties are considered non-attainment areas. In 2016, the American Lung Association ranked Sheboygan, WI as the 22nd most ozone polluted city in the entire country.

Other counties along Wisconsin’s Lake Michigan shoreline have at times also ranked rank high in ozone pollution including Manitowoc, Kewaunee, and Door Counties primarily along a narrow path along the shoreline. Onshore winds and ozone pollution originating outside of Wisconsin is believed to be a cause of these higher levels.

This means that during several days each year, these counties experience high concentrations of ground-level ozone in the air. This can be extremely unhealthy to breathe, especially for people who already have respiratory problems, including - elderly adults, young children, and those who suffer from emphysema, bronchitis, asthma, lung cancer, or other breathing problems. Studies show that hospital admissions and respiratory deaths often increase during periods when ozone levels are high.

In April of 2017, over objections by many state environmental groups, Wisconsin’s Governor Walker recommended to the EPA that all counties in Wisconsin be designated as meeting attainment for the new standard citing, due to out-of-state origin of ozone and the effects of wind on ozone levels.

What is Ozone?

Ozone is a gas that forms when several other types of air pollution, primarily nitrogen monoxide and nitrogen dioxide, recombine after exposure to the sun's radiant energy. It's the main component of the hazy smog that hovers over eastern Wisconsin on certain hot days.

A brown smog streak is sometimes seen across the Fox River Valley skyline. Car and truck emissions are major sources of ozone, as are coal-fired power plants and large manufacturing industries. Gasoline and other petroleum-based chemicals and solvents often vaporize directly into the atmosphere, contributing to ozone. Lawnmowers and the starter fluid for backyard grills are two major residential sources.

For additional information please refer to:
http://dnr.wi.gov/topic/airquality/ozone.html https://www3.epa.gov/airquality/greenbook/ancl.html https://www.epa.gov/sites/production/files/2017-07/documents/wi_2015_ozone_naaqs_designations_0.pdf