EPA Disapproves Wisconsin's Infrastructure SIP for 2006 PM2.5 NAAQS

Summary

The Environmental Protection Agency (EPA) has narrowly disapproved elements of Wisconsin's State Implementation Plan (SIP) submission regarding the infrastructure requirements for the 2006 fine particulate matter (PM 2.5) National Ambient Air Quality Standard (NAAQS), citing concerns over the state's handling of oxides of nitrogen (NOx) as a precursor to ozone.