The U.S. Environmental Protection Agency (USEPA) issued a final rule for determinations of attainment for several areas under the 2008 Ozone National Ambient Air Quality Standards (NAAQS). The final rule was published May 4, 2016 and is effective June 3, 2016. This final ruling pertains to three independent types of determinations for each of the thirty-six (36) areas currently classified as "Marginal" for the 2008 Ozone NAAQS. The three separate determinations are as follows.
- Based on complete, certified, and quality-assured monitoring data from 2012 to 2014, seventeen (17) areas have achieved attainment of the 2008 Ozone NAAQS by the applicable attainment date of July 20, 2015. None of these seventeen (17) areas are located in Illinois.
- Based on the Clean Air Act and USEPA's regulations, one (1)-year attainment data extensions have been granted for eight (8) areas. One of these areas is located in Illinois (St. Louis – St. Charles – Farmington, MO – IL); and the attainment date is extended to July 20, 2016.
- Eleven (11) areas failed to attain the 2008 Ozone NAAQS by the applicable attainment date of July 20, 2015 and will be reclassified as "Moderate." One of these areas is located in Illinois (Chicago – Naperville, IL-IN-WI).
Any state containing any portion of the new "Moderate" areas must submit State Implementation Plan (SIP) revisions by January 1, 2017. The revised SIP must meet the statutory and regulatory requirements that apply to the 2008 ozone nonattainment areas classified as "Moderate."