Wisconsin Department of Natural Resources


Air management Air permitting definitions

Air contaminant

means dust, fumes, mist, liquid, smoke, other particulate matter, vapor, gas, odorous substances or any combination thereof but shall not include uncombined water vapor.

Air contaminant source

or "source" if not otherwise modified, means any facility, building, structure, installation, equipment, vehicle or action that emits or may emit an air contaminant directly, indirectly or in combination with another facility, building, structure, installation, equipment, vehicle or action.

Air permit

is a legal document that lists what your business must do in order to comply with the state and federal air pollution laws. Air permits may contain emission limitations, work practice standards, record keeping requirements, equipment monitoring requirements, and reporting obligations. Failure to follow the requirements listed in your air permit could result in violations of state and federal laws.

Air pollution

means the presence in the atmosphere of one or more air contaminants in such quantities and of such duration as is or tends to be injurious to human health or welfare, animal or plant life, or property, or would unreasonably interfere with the enjoyment of life or property.

Construction permit

This air permit may be required if you are planning to start a new business in Wisconsin or if you wish to expand your business. The permit is required prior to the start of construction or modification of your business if your business will emit air contaminants.

dollar sign - icon The construction permit application fee is $1350.00. You must enclose a check payable to the Department of Natural Resources when you submit the application. Other permit review costs associated with the construction permit review process will vary depending on which air requirements apply to your proposed project that require a detailed review and analysis by the reviewer. For example, the additional review costs could include: $2300.00 Minor Source review fee, $2300.00 for stack test (not required for all), $700.00 air quality analysis, $400.00 for each additional emission source, for two or more units, and $2650.00 fee for expedited review (speeds up the review of your application).

Clock iconThe permit allows a company to build, operate and test the source. It gives you 18 months to get the project going and can have one 18-month extension unless otherwise specified. If you have not started constructing within that time frame, your permit will expire and you'll need a new one if you want to restart the project. Your business will have applied for an Operation Permit or Operation Permit Revision along with your construction permit application. This facility-wide permit will either be issued at the same time as your construction permit or, in some cases, after you have completed any required compliance emission testing for the project. See definition of Operation Permit.

Existing business

is any source that has been in operation for any length of time. Most existing businesses will require an operation permit, but any changes that occurred after 1979 may require a construction permit if either an exemption or permit was not issued at the time.

Expanding business (five types: construction, modification, reconstruction, replacement, relocation)

Construction - To build an entirely new facility or add new equipment at an existing facility. Includes reconstruction and replacement (see below).

Modification - A physical change to, or change in, the method of operation that produces either more air emissions of the same type or different or "new" air emissions.

Reconstruction - To remove old and substitute new components that exceed 50% of the capital cost of building a new source.

Replacement - To dismantle and substitute a process or facility with similar one.

Relocation - To remove a process or facility from one location and place it at a different site or within the same property boundaries.

Generally available control technology (GACT) standards

are federal air pollution rules intended to protect the public from hazardous air pollutant emissions. These standards are less stringent than MACT standards (see below), but they can cover very small businesses. Because GACT standards are included under section 112 of the Clean Air Act Amendments, they may affect a facility's eligibility for permit exemptions.

General permit

is a generic permit issued to cover eligible facilities in a specific industry group. General Permits are drafted, undergo public comment, and are issued only once. Then, facilities that meet a set of eligibility requirement apply for coverage under the specific permit. General permits allow for a very streamlined application process and a turn-around time of 15 days or less on decisions to grant coverage.

Hazardous air pollutants (HAPs)

are compounds that are known or suspected of causing cancer, birth defects, gene mutations, and damage to the respiratory, nervous and immune systems. HAPs are listed in the following regulations:

  • federal HAPs list in s. 112(b), Clean Air Act, includes 188 compounds; and
  • state HAPs list in ch. NR 445, Wis. Adm. Code, includes 550 compounds, with some overlap with the federal HAPs.
Maximum achievable control technology (MACT) standards

are federal air pollution rules intended to protect the public from hazardous air pollutants. MACT standards affect source categories under section 112 of the Clean Air Act Amendments.

Maximum theoretical emissions (MTE)

is the amount of air pollution a source would put into the air if the equipment was operated at maximum production capacity, 24 hours a day, 365 days a year without any control device. When determining annual maximum theoretical emissions, a source shall be presumed to operate 8,760 hours per year unless its physical design precludes 8,760 hours of operation per year. Where a source's physical design restricts the number of hours it may operate, annual maximum theoretical emissions shall be calculated taking this restriction into account. In determining the maximum theoretical emissions of VOCs for a source, the design capacity or maximum production capacity shall include the use of raw materials, coatings and inks with the highest VOC content used in practice by the source. Maximum theoretical emissions considers worst case emissions and reasonable operation conditions (or bottlenecks) in annual calculations.

New source

is a facility, process line or portable source that was either constructed or modified after August 19, 1980 or to which a new emission limit applies, unless it meets certain exemptions:

  • specific exemptions - based on the types of processes you have at your facility and set at maximum or actual operations levels;
  • exemptions based on actual emissions - based on total actual emissions from your facility in a calendar year that stay below specified threshold levels; and
  • general exemptions - based on maximum theoretical pound per hour emission rates of various air pollutants and whether you are affected by federal regulations under new source performance standards or the national emission standards for hazardous air pollutants.

Follow the Permit Primer for details on the exemptions.

Nonattainment area

means an area identified by the department in a document prepared under s. 285.23 (2) where the concentration in the atmosphere of an air contaminant exceeds an ambient air quality standard.

Operation permit

is an air permit that covers all the air polluting activities at an entire facility. Operation permits need to be renewed every 5 years. All facilities that emit air pollution need an operation permit unless they they are exempt. Exemptions are similar to those available for construction permits. Follow the permit primer for the details.

Clock iconThe operation permit is valid for up to five years and may be renewed.

Reasonable available control technology (RACT) sStandards

are state air pollution rules controlling the release of volatile organic compounds (VOCs) based on certain processes or operations at the source. Most of them apply only to businesses that have those specified processes or operations and are located in Wisconsin's non-attainment area or the counties bordering that area. The nonattainment area includes the counties of: Kenosha, Kewaunee, Manitowoc, Milwaukee, Ozaukee, Racine, Sheboygan, Washington and Waukesha.

Registration permit

is a generic permit issued to cover eligible facilities with low air pollution emissions. A Registration Permit is drafted, undergoes public comment, and is issued only once. Then, facilities meeting all the specified eligibility requirements apply for coverage under the permit. Registration Permits allow for a very streamlined application process and a turn-around time of 15 days or less on decisions to grant coverage.

Start of construction, commence construction

"Commence construction" means to engage in a program of on-site construction, including a site clearance, grading, dredging or landfilling specifically designed for a stationary source in preparation for the fabrication, erection or installation of the building components of the stationary source. This includes activities such as:

  • site clearing;
  • grading;
  • dredging;
  • landfilling;
  • changing equipment;
  • substituting equipment; and
  • or even moving the location of equipment.
Volatile organic compounds (VOCs)

means any organic compound which participates in atmospheric photochemical reactions. This includes any such organic compound other than compounds which have been determined to have negligible photochemical reactivity. The latter category includes methane, ethane, methylene chloride (dichloromethane), 1,1,1-trichloroethane (methyl chloroform), acetone, perchloroethylene and many of the chlorofluorocarbons, including CFC-11 (trichlorofluoromethane), CFC-12 (dichlorodifluoromethane), HCFC-22 (chlorodifluoromethane) and HFC-23 (trifluoromethane), to name a few.