Source Identification of Acid Rain Arising over Northeast China: Observed Evidence and Model Simulation
Source Identification of Acid Rain Arising over Northeast China: Observed Evidence and Model Simulation
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中国东北地区酸雨来源识别：观测证据与模型模拟
DOI：
10.4209/aaqr.2015.05.0294
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发表时间：
2016-06-01
影响因子：
4
通讯作者：
Zhang, Qingxin
中科院分区：
文献类型：
--
作者：
Ge, Baozhu;Wang, Zifa;Zhang, Qingxin
酸雨问题已成为近世纪的环境问题，在我国东部和南部地区仍受到人们的关注。然而，过去被认为是非酸雨区的东北地区，近年来却出现了酸雨频发的现象。本文采用线性回归、因子形态分析、反向轨迹、溯源和分数抽样等方法，通过观测和模型模拟分析，探讨了东北两市酸雨频繁发生的原因。丹东和大连），并确定降水中化学离子的贡献源。2007年丹东和大连地区年均pH_（vwa）分别在4.15-4.27和4.5-5.15之间，与我国南方地区的酸度相近。丹东市冬春季降水酸度以硫为主（nssSO_4^（2-）/NO_3^- = 13.1），夏秋两季的土壤养分含量明显高于对照（nssSO_4^（2-）/NO_3^- = 1.05），而大连市全年的nssSO_4^（2-）/NO_3^-估计值约为2.35。反映了当地NOx排放的强烈影响，与丹东相比，移动的交通更加密集。研究结果还揭示了丹东和大连地区典型的物理化学条件，特别是在夏季，区域输送的持续强烈的影响。此外，对冲刷和雨灭机制的分析表明，丹东地区的远距离云内输送（雨灭）比大连地区更明显（丹东地区的局地排放量较小）。研究结果表明，东北地区酸雨污染不仅需要本地减排，还需要区域跨界污染控制。
Acid rain has already been the environment issue for the past century and is still concerned in Southern and Eastern China. However, Northeastern China, considered in the past as non-acid rain area, is reported high frequency of acid rain occurred recently. Through a measurement and model simulation analysis with linear regression technique, factor speciation, backward trajectory, source-tracing and fraction sampling methods, this study aims to investigate the causes of the acid rain frequently occurred in the two Northeastern cities (i.e., Dandong and Dalian) and to identify the contributing sources of the chemical ions in precipitation. The annual averaged pH_(vwa) of 2007 ranged within 4.15-4.27 and 4.5-5.15 over Dandong and Dalian, which suggested the similar acidity with Southern China. The precipitation acidity in Dandong was found to be sulfur dominant in winter-spring (nssSO_4^(2-)/NO_3^- = 13.1) than summer-autumn (nssSO_4^(2-)/NO_3^- = 1.05), whereas in Dalian, estimated ratio nssSO_4^(2-)/NO_3^- was about 2.35 all over the year, reflecting the strong impact of local NOx emissions from a much more intense mobile traffic in comparison with Dandong. The findings also revealed a typical physico-chemical condition with constant strong influence of regional transport over Dandong and Dalian particularly in summer. Besides, analysis of washout and rainout mechanisms showed that the long range transport in-cloud (rainout) was more pronounced in Dandong (with minor local emissions) than Dalian (with more significant local emissions). This study indicates that acid rain pollution in Northeastern China requires much effort, not only in local emission abatement, but also in regional trans-boundary pollution control.