The revision to the Illinois State Implementation Plan (IL SIP) that was submitted on December 2, 2013 was approved by the United States Environmental Protection Agency (USEPA). The submittal was in regards to updating the Illinois air quality standards to reflect the National Ambient Air Quality Standards (NAAQS) that were promulgated by the USEPA through the end of 2012. This included the standards for Sulfur Dioxide (SO2), Ozone (O3), Lead, Particulate Matter with aerodynamic diameter of less than or equal to 2.5 and 10 microns (PM2.5 and PM10) and Carbon Monoxide (CO). Additional elements that were approved and requested to be revised as part of this submittal were to adopt the monitoring methods and test procedures that are promulgated by the USEPA (through the end of 2012), revise or add acronym terms and definitions to be consistent with the USEPA rules.

This rule will be effective July 20, 2015 provided the USEPA does not receive comments by June 19, 2015. More information on filing comments and other details can be found at here.