The ink is barely dry on the reclassification of the Chicago ozone nonattainment area from moderate to serious, under the 2008 ozone National Ambient Air Quality Standards (NAAQS), and the Illinois Environmental Protection Agency (IEPA) intends to seek redesignation to attainment.  According to IEPA staff, the agency has data supporting a request for redesignation to attainment of the 2008 NAAQS based on the latest 2019 monitoring values.  The IEPA’s goal is to submit the request for redesignation to the U.S. Environmental Protection Agency (USEPA) in January 2020.

Just this summer, the IEPA sent letters to affected sources to provide notification of the September 23, 2019 reclassification.  Those letters stated that the IEPA would give sources one year, or until September 23, 2020, to apply for an initial Clean Air Act Permit Program (CAAPP) permit or, to avoid CAAPP permitting, a federally enforceable state operating permit (FESOP) or a revised FESOP, if needed, to remain below the new major source level of 50 tons per year for VOM and NOx.  While the IEPA expects USEPA to take final action redesignating the area to attainment by that date, there are no guarantees.   According to IEPA staff, if there are high temperatures early in the summer and USEPA still has not acted, the redesignation could be in jeopardy,  The IEPA is advising affected sources to be prepared to submit permit applications consistent with the major source levels now in effect by the September 23, 2020 deadline.

Sources should also be aware that, even if the Chicago area is redesignated to attainment under the 2008 ozone NAAQS, the more stringent 2015 ozone NAAQS is still in effect.  Under that standard, Chicago is currently classified as a marginal area.  However, the IEPA staff recently stated that it is a certainty that the area will be bumped-up to moderate sometime in 2022.  The IEPA already has monitoring data showing that the area will not attain the lower 2015 NAAQS by the August 2021 attainment date.  It remains to be seen whether the IEPA will be required to adopt new regulations to meet the 2015 NAAQS, as emissions from mobile sources continue to decline.

The takeaway is that, given this uncertainty, affected VOC and NOx sources should proceed under the assumption that the Chicago area will continue to be designated as a serious area under the 2008 NAAQS, unless and until USEPA states otherwise.  This would include preparing any applications for a CAAPP permit, FESOP or revised FESOP as a result of the bump-up, but holding off on submittal until the current September 23, 2020 deadline, to see how it all plays out.