Abstract:

Urban surface pollutants are the major source of urban rainfall runoff pollution.The buildup and rainfall runoff washoff of urban surface pollutants and the related models are reviewed.Particles settled on the impervious surface can be suspended in the air by external force，for example，wind，and then resettled again in buildup process.Also when it rains，they can enter the surface runoff by raindropinduced ejection and then precipitate again in washoff process.The rest of process may be deduced by analogy.There are many kinds of the models describing the buildup process in the previous research，such as the linear model，the exponential model and the logarithmic model etc.The exponential and its related forms are more authentic comparatively among these models.Antecedent Dry Weather Period (ADWP) is considered as the major impact factor among these models.The washoff model based on the first order reaction kinetics assumption has been setup and been wildly used.In order to improve accuracy of washoff model，the wet weather pollutants have been taken into consideration.At present，much progress has made in the research on urban surface runoff pollution，however，most models rely on experience or extensive calibration by a number of monitoring data which do not clearly represent the physical mechanisms of particles detachment and transportation.As recent emphasis on reducing nonpoint source pollution has increased interest in implementing pollution management practices in urban areas in China，reasonable and predictive models is urgent needed.Greater insight into the underlying physical mechanisms of urban rainfall runoff pollution can provide a better understanding of the movement of pollutants in the urban area and more scientifically justifiable management practices for urban runoff pollution control.

Key words: urban/ surface pollutants/ buildup/ rainfall runoff/ washoff