Department of Environmental Engineering, Technical University of Denmark, Miljøvej, DK-2800 Kgs. Lyngby, Denmark.
Chemosphere. 2011 Nov;85(8):1353-9. doi: 10.1016/j.chemosphere.2011.07.056. Epub 2011 Aug 31.
A modified version of the Multimedia Activity Model for Ionics MAMI, including two-layered atmosphere, air-water interface partitioning, intermittent rainfall and variable cloud coverage was developed to simulate the atmospheric fate of ten low volatility or ionizable organic chemicals. Probabilistic simulations describing the uncertainty of substance and environmental input properties were run to evaluate the impact of atmospheric parameters, ionization and air-water (or air-ice) interface enrichment. The rate of degradation and the concentration of OH radicals, the duration of dry and wet periods, and the parameters describing air-water partitioning (K(AW) and temperature) and ionization (pK(a) and pH) are the key parameters determining the potential for long range transport. Wet deposition is an important removal process, but its efficiency is limited, primarily by the duration of the dry period between precipitation events. Given the underlying model assumptions, the presence of clouds contributes to the higher persistence in the troposphere because of the capacity of cloud water to accumulate and transport non-volatile (e.g. 2,4-D) and surface-active chemicals (e.g. PFOA). This limits the efficiency of wet deposition from the troposphere enhancing long-range transport.
开发了一个用于模拟低挥发性或可离子化有机化学品在大气中归宿的改进版多介质活性溶质分配模型（MAMI），该模型包含双层大气、气-水界面分配、间歇性降雨和可变云覆盖。运行了描述物质和环境输入特性不确定性的概率模拟，以评估大气参数、离解和气-水（或气-冰）界面富集的影响。降解速率和 OH 自由基浓度、干湿期持续时间以及描述气-水分配（K(AW) 和温度）和离解（pK(a) 和 pH）的参数是决定长距离传输潜力的关键参数。湿沉降是一种重要的去除过程，但由于降水事件之间的干燥期持续时间，其效率有限。考虑到基本模型假设，由于云水中积累和运输非挥发性物质（如 2,4-D）和表面活性剂（如 PFOA）的能力，云的存在会导致在对流层中更高的持久性。这限制了从对流层中进行湿沉降的效率，增强了长距离传输。
