As reported in last month's Illinois eNews Regulatory Update, USEPA finalized area designations for the 2008 8-hour ozone National Ambient Air Quality Standard (NAAQS) on April 30th for everywhere but the Chicago metropolitan area.  USEPA could not finalize Chicago area designations at that time due to the late submittal of data from Illinois. As reported then, Madison, Monroe, and St Clair Counties in the Illinois portion of the St. Louis metropolitan area (the "Metro-East" area) has been designated as non-attainment.

On May 31st non-attainment designations for the Chicago area were finalized. In Illinois, Cook, DuPage, Kane, Lake, McHenry, and Will Counties, as well as parts of Grundy (Aux Sable and Goose Lake Townships) and Kendall (Oswego Township) counties were designated non-attainment. Lake and Porter Counties in Indiana and part of Kenosha County (Pleasant Prairie and Somers Townships) in Wisconsin were also included in the non-attainment area.

As compared with the Illinois designations under the 1997 8-hour ozone standard, Jersey County in the Metro-East area moved from non-attainment to attainment. Otherwise, the borders remain the same. However, under the 2008 standard both the Metro-East and Chicago areas have been designated as "marginal" non-attainment whereas they are designated as "moderate" non-attainment under the 1997 standard. This means that once these areas achieve attainment under the 1997 standard the amount of NOx and VOM offsets sources will have to obtain in order to build a new major source or implement a major modification will decrease slightly (and sources in Jersey County will no longer have to comply with non-attainment rules). Otherwise, the permitting process will remain identical to what it has been for the past several years.

In Indiana, several counties, including Lake and Porter Counties, were re-designated as attainment under the 1997 standard in April 2010. Thus, after a two year window with an attainment status, these two counties will be returning to non-attainment.

In Wisconsin, all of Kenosha County, plus Milwaukee, Ozaukee, Racine, Sheboygan, Washington, and Waukesha Counties (the "Milwaukee-Racine" area) are designated as moderate non-attainment under the 1997 standards. Once re-designation under the 1997 standard is complete, only sources in Kenosha's Pleasant Prairie and Somers Townships within the Milwaukee-Racine area will be required to comply with non-attainment rules.

The Chicago, Metro-East, and Milwaukee-Racine and Sheboygan areas are all in the process of obtaining attainment status under the 1997 standard. On December 22, 2011, EPA issued a proposed re-designation approval for the Metro-East area. On February 9, 2012, EPA issued proposed approvals for the Chicago and Milwaukee-Racine and Sheboygan areas.