In December 2013, the Illinois Environmental Protection Agency (IEPA) submitted recommendations to the United States Environmental Protection Agency (USEPA) for non-attainment area designations for the 2012 Particulate Matter less than 2.5 microns (PM 2.5) National Ambient Air Quality Standards (NAAQS). IEPA recommended that the Chicago-Gary-Lake County, IL-IN and St. Louis Metro-East areas that have traditionally been classified as non-attainment areas, be classified as non-attainment for the 2012 PM 2.5 NAAQS. USEPA responded with an initial recommendation that all of Illinois be designated as unclassifiable due to issues with the analysis of the PM samples collected from the state’s monitors. Three (3) years of acceptable data must be available for USEPA to designate areas as attainment or non-attainment. USEPA will issue its final designation in December 2014, and all of Illinois is expected to be designated as unclassifiable for the 2012 PM 2.5 NAAQS, consistent with USEPA’s initial recommendation.
The designation of the entire state as unclassifiable for attainment status will not have an effect on current permitting projects. Areas that are unclassifiable are governed by the attainment area new source review (NSR) rules. The Chicago-Gary-Lake County, IL-IN area was classified as in attainment for the 1997 PM 2.5 standard in October 2013, so permitting projects will continue to be governed by the attainment area NSR rules. The St. Louis Metro East area is currently classified as moderate non-attainment for the 1997 PM 2.5 standard, so permitting projects will continue to be governed by the non-attainment NSR rules.