Air Plan Approval; Illinois; NAAQS Updates

The Environmental Protection Agency (EPA) is approving revised rules submitted by the State of Illinois as State Implementation Plan (SIP) revisions. The submitted rules update Illinois' ambient air quality standards to include the 2012 primary National Ambient Air Quality Standard (NAAQS) for fine particulate matter (PM2.5), add EPA-promulgated monitoring methods, and address the ``sunset provisions'' in our regulations. In addition, the revised rules contain the timing requirements for the ``flagging of exceptional events'' and the submitting of documentation supporting the determination of exceptional events for the 2012 primary annual PM2.5 standard.