Abstract: Exchanges at the air-soil surface play an important role in controlling the regional and global transport, redistribution and fate of POPs. The main processes contributing to the exchanges at air-soil interface are wet deposition, dry deposition and volatilization from the soil. Furthermore, the diffusive exchange of POPs is the key process affecting the matter of“source or sink”. Diffusive exchange between air and soil is driven by the concentration gradient between air and soil. Soil-air partitioning is mainly dependent on physical and chemical properties of compounds, temperature and soil organic matter. As the production of most POPs has been banned in many countries after 1980s, the soil of mid-latitude area is gradually becoming a secondary source of the lighter molecular weight compounds to the atmosphere and a sink for the heavier ones. Air-soil exchange direction is affected by temperature and shows a seasonal trend such that soil is a source in summer and a sink in winter. Fugacity model is a powerful tool to estimate the air-soil exchange fluxes quantitatively. This paper reviewed the research progress on the above-mentioned scientific topics, pointed out the research areas that need more focus, and made suggestions for further studies.

Key words: air-soil exchange, deposition, fugacity model, interface, persistent organic pollutants(POPs)