Approval and Promulgation of State Implementation Plan; Illinois

In this action, EPA is approving, as revisions to the Illinois State Implementation Plan (SIP): Rate-Of-Progress (ROP) plans for the purpose of reducing Volatile Organic Compound (VOC) emissions in the Chicago ozone nonattainment area (Cook, DuPage, Kane, Lake, McHenry, and Will Counties, Oswego Township in Kendall County, and Aux Sable and Goose Lake Townships in Grundy County) and in the Metro-East St. Louis ozone nonattainment area (Madison, Monroe, and St. Clair Counties) by 15 percent by November 15, 1996, relative to 1990 baseline emissions; contingency plans for the same ozone nonattainment areas for the purpose of achieving an additional 3 percent VOC emission reductions beyond the 15 percent ROP plans; and transportation control measures (TCM) for the Metro-East St. Louis area. Emissions of VOC react with nitrogen oxides in sunlight to form ground-level ozone, commonly known as smog. High concentrations of ground-level ozone can aggravate asthma, cause inflammation of lung tissue, decrease lung function, and impair the body's defenses against respiratory infection. In this action, EPA is approving Illinois' 15% ROP and contingency plans through a ``direct final'' rulemaking; the rationale for this approval is set forth below.