Approval and Promulgation of Air Quality Implementation Plans; Illinois; NAAQS Update

The Environmental Protection Agency (EPA) is proposing to approve a revision to the Illinois State Implementation Plan. The submitted state rule revisions update Illinois' ambient air quality standards for sulfur dioxide, ozone, nitrogen dioxide, lead, fine particulate matter, particulate matter, and carbon monoxide and bring them up to date (through 2012) with EPA-promulgated National Ambient Air Quality Standards. The SIP revision also adopts EPA-promulgated monitoring methods and test procedures for the revised state air quality standards.