The significance of international transport of air pollutants

Once thought of as a local issue, air pollution is now recognized as a complex problem subject to local, regional, hemispheric, and global influences. While domestic sources are the primary contributors to most of our nation's air quality problems, the United States is both a source and a receptor for the international transport of air pollutants. The long-range transport of air pollution from international sources and its potential impacts on air quality and regional climate in the United States has received increasing attention in the scientific literature and popular media.

The National Research Council (NRC) was asked by four U.S. federal agencies (EPA, NASA, NOAA, NSF) to summarize the state of knowledge regarding the international flows of air pollutants into and out of the United States; and to consider the impact of these flows on the achievement of environmental policy objectives related to air quality or pollutant deposition in the United States and abroad. The pollutants that were considered include ozone and precursors, fine particles and their precursors, mercury, and persistent organic pollutants. This study is intended inform efforts by the U.S. government to develop domestic and international environmental policies, and to contribute to an international assessment being conducted under the Convention on Long-range Transboundary Air Pollution's Task Force on Hemispheric Transport of Air Pollution.

In this conference presentation, we will discuss the key findings and recommendations that emerged from the study, with a focus on the needs for advancing meteorological models and for forging closer cooperation between the meteorology and atmospheric chemistry research communities.