Approval and Promulgation of Implementation Plan; Michigan Detroit-Ann Arbor NOINFX Exemption

The Environmental Protection Agency is granting an exemption to the Detroit-Ann Arbor ozone nonattainment area from applicable oxides of nitrogen (NO<INF>X) requirements found in the Clean Air Act (Act). Approval of the exemption would apply for various NO<INF>X requirements including adoption and implementation of regulations addressing general conformity, transportation conformity, inspection and maintenance, reasonably available control technology, and new source review. The State of Michigan submitted a NO<INF>X exemption request on November 12, 1993. A subsequent letter dated May 31, 1994 clarified this earlier submittal. This request is based on the fact that ozone monitoring in the Detroit-Ann Arbor area indicates that the average number of exceedances of the National Ambient Air Quality Standard for ozone during the most recent 3-year period, 1991 to 1993, is fewer than one per year. Given this monitoring data, Michigan petitioned for an exemption from the NO<INF>X requirements based on a demonstration that additional reductions of NO<INF>X would not contribute to attainment of the ozone standard.