Safety and Environmental Technology Group, ETH Zürich, Zürich - 8093, Switzerland.
Chemosphere. 2009 Oct;77(4):495-500. doi: 10.1016/j.chemosphere.2009.07.051. Epub 2009 Aug 21.
Soil and marine aerosol suspension are two physical mass transfer processes that are not usually included in models describing fate and transport of environmental pollutants. Here, we review the literature on soil and marine aerosol suspension and estimate aerosol suspension mass transfer velocities for inclusion in multimedia models, as a global average and on a 1 x 1 scale. The yearly, global average mass transfer velocity for soil aerosol suspension is estimated to be 6 x 10(-10)mh(-1), approximately an order of magnitude smaller than marine aerosol suspension, which is estimated to be 8 x 10(-9)mh(-1). Monthly averages of these velocities can be as high as 10(-7)mh(-1) and 10(-5)mh(-1) for soil and marine aerosol suspension, respectively, depending on location. We use a unit-world multimedia model to analyze the relevance of these two suspension processes as a mechanism that enhances long-range atmospheric transport of pollutants. This is done by monitoring a metric of long-range transport potential, phi-one thousand (phi1000), that denotes the fraction of modeled emissions to air, water or soil in a source region that reaches a distance of 1000 km in air. We find that when the yearly, globally averaged mass transfer velocity is used, marine aerosol suspension increases phi1000 only fractionally for both emissions to air and water. However, enrichment of substances in marine aerosols, or speciation between ionic and neutral forms in ocean water may increase the influence of this surface-to-air transfer process. Soil aerosol suspension can be the dominant process for soil-to-air transfer in an emission-to-soil scenario for certain substances that have a high affinity to soil. When a suspension mass transfer velocity near the maximum limit is used, soil suspension remains important if the emissions are made to soil, and marine aerosol suspension becomes important regardless of if emissions are made to air or water compartments. We recommend that multimedia models designed to assess the environmental fate and long-range transport behavior of substances with a range of chemical properties include both aerosol suspension processes, using the mass transfer velocities estimated here.
土壤和海洋气溶胶悬浮是两种物理传质过程，通常不包括在描述环境污染物归宿和迁移的模型中。在这里，我们回顾了关于土壤和海洋气溶胶悬浮的文献，并估计了气溶胶悬浮传质速度，以便纳入多媒体模型，作为全球平均值和 1x1 比例尺。土壤气溶胶悬浮的年全球平均传质速度估计为 6x10(-10)mh(-1)，大约小一个数量级，而海洋气溶胶悬浮的传质速度估计为 8x10(-9)mh(-1)。这些速度的月平均值可以高达 10(-7)mh(-1)和 10(-5)mh(-1)，分别取决于位置。我们使用一个单位世界多媒体模型来分析这两个悬浮过程作为增强污染物长距离大气传输的机制的相关性。这是通过监测长距离传输潜力的指标 phi1000 来完成的，phi1000 表示模型中源区排放到空气中、水中或土壤中的部分，在空气中达到 1000 公里的距离。我们发现，当使用每年全球平均传质速度时，海洋气溶胶悬浮仅使空气和水排放的 phi1000 略有增加。然而，海洋气溶胶中物质的富集或海洋水中离子和中性形式之间的专化可能会增加这种表面到空气转移过程的影响。在排放到土壤的情况下，土壤气溶胶悬浮可能是土壤到空气转移的主要过程，对于与土壤有高亲和力的某些物质而言。当使用接近最大极限的悬浮传质速度时，如果排放到土壤中，土壤悬浮仍然很重要，而无论排放到空气还是水隔室中，海洋气溶胶悬浮都会变得重要。我们建议，旨在评估具有一系列化学性质的物质的环境归宿和长距离迁移行为的多媒体模型应包括这两种气溶胶悬浮过程，并使用这里估计的传质速度。
