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EPA and Wisconsin Announce Inland Sheboygan County Area Now Meets Federal Air Quality Standard for Ozone

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Joshua Singer (

Sheboygan County, Wis. – Today, the U.S. Environmental Protection Agency (EPA) and Wisconsin Department of Natural Resources (WDNR) announced their proposal to formally redesignate the Inland Sheboygan area in Sheboygan County to attainment of the 2008 National Ambient Air Quality Standard (NAAQS) for ground-level ozone. Recent air monitoring data show the area now meets the ­­national standard set to protect public health.


“The air in the Inland Sheboygan area is cleaner as a result of the cooperation between local, state and federal governments, helping to protect the health of 54,000 people,” said EPA Deputy Regional Administrator Cheryl Newton.


All of Sheboygan County was designated in 2012 as a nonattainment area for the 2008 ozone NAAQS based on an analysis including data from an air quality monitor located on the Lake Michigan shoreline. EPA’s proposed redesignation of the Inland Sheboygan area is based on air quality data from a more recently installed monitor, located three miles inland, which EPA and WDNR began operating in 2014. Three years of recent data collected from the inland air quality monitor show the area is attaining EPA’s 2008 NAAQS for ozone.


According to emissions modeling, federal regulations that set fuel and motor vehicle emission standards helped to improve ozone concentrations in the area. EPA is proposing to redesignate the Inland Sheboygan area to attainment and to approve Wisconsin’s plan to ensure that the area will continue to meet the ozone standard. If the redesignation is finalized, the Inland Sheboygan area will be in attainment for all NAAQS. The area’s redesignation will not be final until the public has an opportunity to comment on the proposal. If the Inland Sheboygan area is redesignated, local businesses will face fewer air permitting restrictions.


Nationally, the concentration of ground level ozone has decreased 17% from 2000 to 2017. All other air pollutants regulated under NAAQS – sulfur dioxide, lead, carbon monoxide, nitrogen dioxide and particulate matter – have also significantly decreased thanks to the various air quality management and control strategies developed and implemented at the local, state, regional, and national level.


Ground level ozone is not emitted directly into the air but is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOCs. Reducing ozone will help people to experience fewer health problems including chest pain, coughing, throat irritation and congestion. Less ground-level ozone will also help to avoid worsening conditions such as bronchitis, emphysema and asthma, and it will help to avoid reducing lung function or inflaming the linings of the lungs. Children will especially benefit from reduced exposure to ozone because their lungs are still developing.


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