On February 22, 2016, the Wisconsin Department of Natural Resources (WDNR) finalized several guidance documents that will change the way the Department regulates particulate matter with an aerodynamic diameter of 2.5 microns or less (PM2.5).  In July 2015, WDNR released four (4) draft guidance documents that addressed new policies for permitting and modeling of PM2.5 in Wisconsin.  The WDNR examined the primary and secondary formation of PM2.5, along with statewide monitoring and other scientific evidence, and concluded that only combustion and high temperature industrial sources are considered to emit significant amounts of PM2.5.  Additionally, WDNR made a finding through a weight of evidence approach that direct emissions of PM2.5 do not cause or exacerbate a violation of the ambient air quality standards for increment (See the article Several New WDNR Proposed Program Guidance Documents Open for Public Comment, posted on July 30, 2015, below, for a more information on the draft guidance).

WDNR received over 400 comments on the proposed guidance documents and has been working over the last several months to address those comments and update the guidance as necessary.  WDNR made some changes to the guidance documents based on the comments received, including the addition of language that requires certain situations to estimate PM2.5 emissions from low temperature sources.  If a source or project PM2.5 emissions from high temperature sources is greater than 80% of the major source thresholds then PM2.5 emissions from low temperature sources would need to be estimated.  Similarly, for existing major sources, if the increase in emissions from high temperature sources that are part of the project are greater than 80% of the PSD significant emission rate then the PM2.5 emission estimates from the low-temperature sources would need to be included.

All four final guidance documents, and the appropriate WDNR contact for each, are available on the WDNR website until March 16, 2016.  If you have any questions about these final guidance documents, or how they may impact your facility, please contact Jon Frost by email, or by phone at (651) 275-9900 x6.