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1G - Long-range transport of pollutants (chemicals) (WE13/1) Assessing the importance of various air-surface exchange processes in estimating the atmospheric travel potential of POPs. Cousins, Ian1, Gouin, Todd2, Mackay, Donald2, 1 Institute of Applied Environmental Research, Stockholm, Uppland, Sweden2 Trent University, Peterborough, Ontario, Canada ABSTRACT- A number of modelling approaches have been developed to estimate the atmospheric transport potential (ATP) of persistent organic pollutants (POPs). These models rely on an imperfect understanding of air-surface exchange processes. For example, many processes have typically been neglected when describing air-soil exchange, such as bioturbation and macropore flow, while the soil depth in the majority of models is often fixed at a constant value. Furthermore, it is common to only treat a bare soil surface in the model even though it is likely that foliage-air exchange may play an important role in ATP. In this study the Transport and Persistence Level III model (TaPL3) is modified to include vegetation, bioturbation, effective soil depth and macropore flow to determine how these parameters combine to affect the ATP of selective POPs. The compounds are compared in terms of both their characteristic travel distance and rankings. In addition, the effects of these parameters on the "stickiness" of a chemical to the surface and the number of hops that a chemical can undergo before being degraded are examined. It is our belief that the identification of the most sensitive model parameters affecting air-surface exchange and thus ATP of POPs will help better focus future experimental research in this area. Key words: atmosphere, transport, POP, soil |
