Bi-national and regional issues in air quality science and policy

Abstract

Abstract Over the last several years, efforts have increased towards developing policies that address the ground-level ozone problem as a regional, rather than local, issue in eastern North America. While scientific knowledge has existed since at least the 1970s that ground-level ozone and its precursors can be transported hundreds of kilometers from their points of origin, the Clean Air Act did not specifically establish regional approaches until the Amendments of 1990 created the Ozone Transport Region in the northeastern United States. In the last 2 yr, there has been a dramatic increase in regional efforts to reduce the movement of ozone. The Ozone Transport Assessment Group (OTAG), a cooperative effort among 37 eastern states and the District of Columbia, developed recommendations to address the transport of ozone and its precursors over a large area of the eastern United States. On the basis of OTAG findings and existing scientific knowledge, EPA and the states have initiated regulatory efforts for the first time to require ozone pollution reductions based on regional impacts. This paper provides an overview of the scientific basis that supports the recent actions to implement regional control measures. Recent work that brings the eastern Canada provinces into a regional framework for transported ozone and its precursors will also be presented.