Air Plan Approval; Wisconsin; Particulate Matter Standard

The Environmental Protection Agency (EPA) is proposing to approve a January 4, 2018, request by the Wisconsin Department of Natural Resources (Wisconsin) to revise its state implementation plan (SIP) for fine particulate matter (PM2.5). Wisconsin updated its ambient air quality standards for PM2.5 to be consistent with EPA's 2012 revisions to the PM2.5 national ambient air quality standards (NAAQS). Wisconsin also revised its incorporation by reference rule to update references to the EPA monitoring methods.