Conceptual overview of hemispheric or intercontinental transport of ozone and particulate matter

Abstract

When the Executive Body to the Convention on Long-range Transboundary Air Pollution took the decision to establish the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) in December 2004, it was on the basis of a growing understanding of the issues surrounding the hemispheric and intercontinental transport of air pollutants. It was recognised that whilst current regional emissions on their own created pollution levels that exceeded internationally-agreed air quality objectives, hemispheric transport could exacerbate local and regional air quality problems. Two particular pollutants of concern, and the focus of this report, are ozone and particulate matter (PM), known for their detrimental impacts on human health (these impacts and others are described in Chapter 5). There was well-documented evidence for the intercontinental transport of ozone and PM but, at that time, the significance of this intercontinental influence on the design of air pollution control policies was not well understood. The European Union, in drawing up its Thematic Strategy on Clean Air for Europe during 2004, became aware of the significance of intercontinental transport and the importance of sources of pollution beyond its borders and sphere of influence, in meeting its air quality goals.