The source-receptor relation of wet deposition has been a continuous issue in studies of regional environmental pollution over the past two decades. In the absence of direct observational evidence, the problem is difficult to solve—a topic of broad international debate since the turn of the present century. In the present study, a variety of methods focused on the sources of the wet deposition of acidic substances, like sulfate and nitrate, were used to investigate the precipitation over the Yangtze River Delta (YRD) during 2007. Back-trajectory analysis associated with the observation data and a source tracing method coupled with the Nested Air Quality Prediction Modeling System (NAQPMS) are proved to be effective methods for investigating the sources of wet deposition over the YRD. Comparison among the back-trajectory, footprint, and NAQPMS results shows good consistency, both qualitatively and quantitatively. The most important contributor to acidic substances in the YRD, as well as heavy acid rain over the region, is the anthropogenic pollution from East China, which accounts for more than 70%.
基于多方法的长三角地区酸雨空间贡献源解析追踪区域环境污染的湿沉降源追踪已经成为过去20年里持续关注的研究热点。由于直接观测的缺失，湿沉降源追踪是一个科学难题，因此成为自上世纪以来国际上广泛争论的焦点问题。本研究利用多种方法，针对酸性物质的湿沉降来源，如硫酸盐、硝酸盐，对2007年长三角地区的降水组分进行了分析。结果表明，基于观测数据的后向轨迹分析和与NAQPMS模式耦合的源追踪方法，能够有效追踪长三角湿沉降来源。后向轨迹、足迹和NAQPMS三种方法的结果在定性和定量分析中均表现较高一致性。中国东部地区的人类活动污染是长三角地区的酸物质和严重酸雨的最主要贡献来源，占全部来源的70%以上。