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News Brief: Ozone Transport Clouds Redesignation Efforts

Fall 1995

The 1995 ozone season in Wisconsin came to a close on October 15, 1995. Everyone in the State had been hopeful that the summer would bring few exceedances of the ozone standard and that Wisconsin would be in a position to request that the Environmental Protection Agency ("EPA") redesignate Southeastern Wisconsin — consisting of Milwaukee, Kenosha, Racine, Ozaukee, Waukesha, and Washington counties — from "severe" ozone nonattainment to attainment. Indeed, redesignation would bring about relief from some of the stringent Clean Air Act requirements that currently apply in the area, such as the Employee Commute Options Program, Reformulated Gasoline, and offset requirements for new and modified sources.

Offset requirements are especially costly for industry. New and modified sources with "worst case" projected emissions of 25 or more tons per year of volatile organic compounds ("VOC") must offset the projected emissions at a 1.3 to 1 ratio. Consider, for example, a new source with 100 tons per year of projected emissions. Such source must purchase 130 tons "credits" generated by emission reductions at other sources. Offsets typically range from $4000 to $8000 per ton.

As it turns out, Summer 1995 was hot and smoggy and a number of ozone exceedances were recorded at monitors in the State. The National Ambient Air Quality Standard ("NAAQS") for ozone requires reporting of an ozone exceedance to the EPA whenever the ozone concentration equals or exceeds 125 ppb, averaged over one hour. Exceedances were recorded on six days at thirteen separate monitors in the State (there are a total of nineteen monitors). In particular, exceedances of the ozone standard were recorded on June 16, June 17, July 12, July 30, July 31, and September 5. Chiwaukee Prairie in Kenosha County recorded the greatest number of exceedances, altogether four. The highest exceedance, 146 ppb, was measured at the Slinger, Washington County monitor on July 12.

Pursuant to the Clean Air Act, redesignation is contingent upon, among other requirements, a demonstration that there are no more than an average of one exceedance of the ozone standard per year, over each three-year period. Being that there were four ozone exceedances recorded this season at the Chiwaukee Prairie monitor alone, the summers of 1996, 1997, and 1998 must be "clean" before a redesignation request can be made. In fact, Wisconsin will not now be able to seek redesignation until 1999, at the earliest. As a result of the large number of ozone exceedances, the most since the summer of 1991, hopes for redesignation have been dashed. Stationary and mobile sources of air emissions in Southeastern Wisconsin will continue to be subject to numerous Clean Air Act requirements.

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