AVS 47th International Symposium
    Incorporating Principles of Industrial Ecology Tuesday Sessions
       Session IE-TuM

Invited Paper IE-TuM8
Multi-phase Atmospheric Chemical Processes: A Major Gap in Understanding Regional to Global Air Pollution Issues

Tuesday, October 3, 2000, 10:40 am, Room 304

Session: Methods of Industrial Ecology Analysis / Global Concerns
Presenter: L. Barrie, Pacific Northwest National Laboratory
Correspondent: Click to Email
Chemicals from natural or anthropogenic activities that are released to the atmosphere as gases or particles are dispersed and transported on the winds. Their residence time and hence, range of influence, is determined by the processes of chemical and physical transformation, air-surface exchange and precipitation scavenging. Multi-phase chemistry involving interactions of gases with solids or liquids in the atmosphere or at the Earth’s surface is often a major obstacle in understanding environmental chemical cycles and hence establishing effective pollution abatement strategies. There are a variety of pollution issues operating on a range of scales from local to global that threaten the quality of life on this planet. They include: urban smog (e.g. ozone and particulate matter), regional acidification/toxification and visibility reduction, global stratospheric ozone depletion and climate change. An understanding of multi-phase reactions is complicated by the largely unknown, highly variable nature of liquid/solid particles in the atmosphere. These include atmospheric aerosols (0.001 to 10 micrometers), cloud droplets and ice (1 to 20 micrometers) and rain/snow particles (20 to 20000 micrometers). They range greatly in composition and ionic strength (6x10@super -6@ to 10 molal). The interaction of gases with particles involves unreactive phase-partitioning processes as well as reactive kinetic processes. In the case of persistent semi-volatile substances such as herbicides, pesticides and polycyclic aromatic compounds, the environmental pathways are often dominated by the former process, In contrast, many substances are chemically produced or transformed during gas-particle interactions. There is a need to understand the nature of organic compounds in atmospheric particles and the basic physical chemistry of the interaction of these mixtures with water vapour and other gases.