Permitting requirements for nonattainment areas in Wisconsin
Areas that have been designated as being in "nonattainment" of a national ambient air quality standard (NAAQS) have more restrictive permitting requirements. This page shows current Wisconsin nonattainment areas and summarizes the applicable permitting requirements for major sources of emissions within these areas. The information presented here is only intended to provide an overview of the applicable requirements. Contact the Air Program for more detailed information about state permitting regulations or with questions related to a specific permit situation. Contact information is included at the bottom of this page.
Click on a county below for a summary of the applicable permitting requirements based on nonattainment area designations as of July 10, 2020.
Please note: Graphical representations of attainment/nonattainment areas are approximate. Contact the DNR staff with questions on the current status of specific locations.
Explanation of information provided in the map legend
Major emission sources for construction permitting purposes in areas that meet or attain the NAAQS are covered by the prevention of significant deterioration (PSD) program. In contrast, major emission sources in nonattainment areas are covered by the nonattainment new source review (NNSR) program.
In general, the NNSR program is more stringent than the PSD program because the goal of NNSR is to improve air quality to attain the NAAQS. The emissions threshold for determining whether a source is subject to major source permitting is usually lower for NNSR than PSD. Projects covered by PSD are required to control emissions to a level defined as best available control technology (BACT), which allows consideration of economic feasibility of the controls. However, projects covered by NNSR are required to control emissions to the level defined as lowest achievable emission rate (LAER), which cannot, by law, consider costs.
Major construction covered by NNSR also requires the permit applicant to offset the project's emissions according to a ratio that depends on the severity of nonattainment. Permit applicants can use internal offsets by establishing emission reductions from their own operations, or an applicant can use emission reduction credits. The offsets must represent surplus, permanent, quantifiable and federally enforceable emissions reductions.
Based on nonattainment status, the map above shows which permitting program currently applies in each area in Wisconsin, along with the associated major source threshold and offset ratio (as applicable).
Refer to air permit options for more information about construction permits.
- Prevention of Significant Deterioration requirements: ch. NR 405, Wis. Adm. Code
- Nonattainment NSR requirements: ch. NR 408, Wis. Adm. Code
- Construction permit requirements (apply to projects in all areas): ch. NR 406, Wis. Adm. Code
For more information on major source permitting thresholds, contact:
Air Permits and Stationary Source Modeling Section Chief
For more information on state implementation plans (SIPs), control strategies and current air quality, contact:
Air Quality Planning and Standards Section Chief