Ozone Control Strategies and Regulations

For areas in Wisconsin that are not in attainment with federal air quality standards for ozone, or in danger of being designated as nonattainment areas, the DNR and local partners have implemented several programs to reduce ground-level ozone.

For an overview of ozone standards, please visit the Standards and Nonattainment Designations page. For links to technical information on ozone rules and standards, prease visit the Resources and Air Monitoring Data page.

Reasonably Available Control Technology (RACT) Standards

RACT is a requirement of the federal Clean Air Act. For ozone control, all major sources of volatile organic compounds (VOCs) or nitrogen oxide compounds (NOx) in nonattainment areas must apply control technologies that are available and have reasonable costs. More information on RACT can be found on EPA’s Technology Transfer Network [exit DNR].

VOC RACT

In Wisconsin, RACT rules cover VOC sources. In general, the rules are designed to limit VOC emissions associated with the use, storage and handling of these ozone-forming compounds. However, control technologies and geographic coverage of these rules varies depending on the source types and when the applicable rule was created. More information on RACT rules can be found in chs. NR 419-425, Wis Adm. Code [exit DNR]

NOx RACT

In Wisconsin, RACT rules cover major stationary sources in Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Washington and Waukesha counties. The rules are designed to limit NOx emissions from stationary combustion sources such as boilers, heat treating and engines. More information on RACT rules can be found in ch. NR 428, Wis. Adm. Code [PDF 136KB, exit DNR].

Mobile Sources

There are several state and federal pollution-control programs aimed at mobile sources--including both highway vehicles, such as cars, and off-road equipment, such as all-terrain vehicles (ATVs). The federal government also regulates the fuels these vehicles and other equipment use, with a goal of having cleaner-burning fuels that do not contribute as much air pollution. Regulations include motor vehicle emission standards, vehicle inspection and maintenance, the required use of reformulated gasoline, ultra-low sulfur diesel fuel, low sulfur gasoline, and gasoline vapor-recovery programs.

Interstate Transport

Pollutants do not respect political boundaries. Instead, they may be transported great distances by wind and may harm human health in other states downwind of a particular pollution source. Ozone, along with fine particles and mercury, can be transported hundreds of miles or more from where it is formed.

Several federal rules deal with the problem of pollutants that cross state boundaries. The Clean Air Interstate Rule (CAIR) applies to ozone and fine particles (often referred to as particulate matter, or PM). CAIR created an emissions "budget" of nitrogen oxides (NOx) and sulfur dioxide (SO2). In addition, the federal Clean Air Mercury Rule (CAMR) requires all states to limit mercury emissions.

Attainment Demonstrations

An attainment demonstration is a plan that ensures that an area with an air quality problem (nonattainment area) will attain the air quality standards in the requisite time period. The plan contains the necessary analyses and control program to demonstrate that enough pollutants have been removed from the atmosphere so that pollutant concentrations will not exceed the federal standard in the future. As of the end of the 2007, ozone season, there were four areas in Wisconsin with measured violation of the federal 8-hour ozone standard: the six-county area around Milwaukee, Door, Manitowoc and Sheboygan counties. The DNR is currently developing attainment demonstrations for these areas.

EPA Guidance on Ozone Attainment Demonstrations [PDF 1MB]

Voluntary Reduction Programs

Governments, businesses and partner organizations have developed local and regional voluntary programs to reduce air pollution. Find out more on our voluntary programs page.