The enhanced dissolution of some chlorinated hydrocarbons and monocyclic aromatic hydrocarbons in rainwater collected in Yokohama, Japan
The enhanced dissolution of some chlorinated hydrocarbons and monocyclic aromatic hydrocarbons in rainwater collected in Yokohama, Japan
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DOI：
10.1016/j.atmosenv.2004.03.053
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发表时间：
2004-08
影响因子：
5
通讯作者：
H. Okochi;D. Sugimoto;M. Igawa
中科院分区：
文献类型：
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作者：
H. Okochi;D. Sugimoto;M. Igawa
通过对1999 ~ 2000年日本横滨市神奈川大学校园内的大气和雨水同时连续采样，研究了雨滴对挥发性有机物（CHs和MAHs）的湿清除过程。它们在125个雨水中的体积加权平均浓度分别为二氯甲烷4.98 nM、甲苯3.71 nM、苯2.00 nM、1，2-二氯乙烷0.93 nM、邻二甲苯0.62 nM、间对二甲苯0.57 nM、对二氯苯0.51 nM和三氯亚甲基0.35 nM。它们的雨水浓度不依赖于降雨强度，其浓度的时间变化类似于气相浓度。然而，CHs和MAHs在雨水中的溶解度大于其地面气相浓度和温度校正后的亨利定律常数的预期值。一个简单的云下清除模型，这是由莱文和施瓦茨（大气。Environ. 16（1982）1725）可以解释降雨强度的独立性，但不能解释它们在雨水中的溶解增强。研究结果表明，基于亨利定律平衡的估算浓度大大低估了CHs和MAHs在地面上的湿沉降通量。
By simultaneous sequential sampling of gas and rainwater from 1999 to 2000 in the campus of Kanagawa University in Yokohama, Japan, we investigated the wet-scavenging process of volatile organic compounds, some chlorinated hydrocarbons (CHs) and monocyclic aromatic hydrocarbons (MAHs), via rain droplets. Their volume-weighted mean concentrations in 125 rainwater were 4.98nM for dichloromethane, 3.71nM for toluene, 2.00nM for benzene, 0.93nM for 1,2-dichloroethane, 0.62nM for o-xylene, 0.57nM for m,p-xylene, 0.51nM for p-dichlorobenzene, and 0.35nM for trichloromethylene. Their rainwater concentrations did not depend on the rainfall intensity, and the temporal variation of their concentrations was similar to that of gas-phase concentrations. The dissolution of CHs and MAHs into rainwater, however, was larger than expected from their gas-phase concentrations at the ground and their temperature-corrected Henry's law constants. A simple below-cloud scavenging model, which was developed by Levine and Schwartz (Atmos. Environ. 16 (1982) 1725) could explain the independence of the rainfall intensity but not explain their enhanced dissolution in rainwater. The results of this study indicate the estimated concentrations, which were based on the Henry's law equilibrium, considerably underestimate the wet-deposition fluxes of CHs and MAHs onto the ground.