Seasonal and rainfall-type variations in inorganic ions and dicarboxylic acids and acidity of wet deposition samples collected from subtropical East Asia
Seasonal and rainfall-type variations in inorganic ions and dicarboxylic acids and acidity of wet deposition samples collected from subtropical East Asia
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DOI：
10.1016/j.atmosenv.2011.04.001
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发表时间：
2011-07
影响因子：
5
通讯作者：
Y. Tsai;Li-Ying Hsieh;S. Kuo;Chien-Lung Chen;Pei-Ling Wu
中科院分区：
文献类型：
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作者：
Y. Tsai;Li-Ying Hsieh;S. Kuo;Chien-Lung Chen;Pei-Ling Wu
在东亚亚热带地区收集了3年零8个月的降雨样本。本研究将这些降雨分为不同的雨型，并加以分析，以评估其离子组成及其对台湾南部湿沉降酸度的影响。只有4%的样品的pH值<5.0，表明研究区域没有受到酸雨的显著影响。按降雨类型划分的体积加权平均（VWM）pH值为春雨5.74，台风雨5.56，夏雨5.46，台风外环流（TOC）雨5.45，梅雨5.32和秋冬雨5.29。稀释效应对不同降雨类型的等效离子浓度有重要影响。HCO 3 −、SO 42 −和Cl−被检测为主要阴离子，而NH 4+、Na+和Ca 2+是主要阳离子。除台风雨和春雨外，所有降水中的主要离子种类都是CO2衍生的HCO 3 −，其中主要离子种类分别是Na+、Cl−和Ca 2+。除HCO 3-外，梅雨中的主要形态为NH 4+、Na+和Ca 2+，TOC雨和夏雨中的次级光化学产物为SO 42-、NO3-和NH 4+，秋冬雨中的主要形态为Na+和Ca 2+。算术平均值的计算表明，二羧酸之间的总离子浓度的0.25%和0.53%，其中，草酸贡献最少（81.3%的二羧酸）的TOC雨和最（96.1%的二羧酸）春雨，暗示在后者的长距离传输。湿沉降成分的差异表明是降雨期间当地排放和远距离迁移（因此是主导风向）的差异以及每种降雨类型的降雨频率和降雨量的差异造成的。主成分分析进一步表明，与交通有关的和工业的有机和无机污染物，其二次光化学产品，海盐，和灰尘是湿沉降的重要贡献者。此外，丙二酸琥珀酸（M：S比）的比例表明，交通和二次光化学反应是主要的贡献者，但总有机碳雨，其中的M：S比为4.54表示相对丰富的污染物从二次光化学反应。离子平衡（IB）比率分析证明了本研究结果的有效性。
Rainfall samples were collected over a period of 3 years and 8 months in subtropical East Asia. They are categorized into different rainfall types and analyzed to assess the ionic composition and its effect on the acidity of wet deposition in southern Taiwan. Only 4% of samples had a pH of <5.0, indicating that the study area is not impacted significantly by acid rain. The volume-weighted mean (VWM) pH by rainfall type was Spring Rain 5.74, Typhoon Rain 5.56, Summer Rain 5.46, Typhoon Outer Circulation (TOC) Rain 5.45, Plum Rain 5.32 and Autumn–Winter Rain 5.29. Dilution effects were important to the equivalent ionic concentration of different rainfall types. HCO3−, SO42−and Cl−were detected as major anions whereas NH4+, Na+and Ca2+were major cations. CO2-derived HCO3−was the major ionic species in all but Typhoon Rain and Spring Rain, in which the major species were Na+and Cl−and Ca2+, respectively. Excluding HCO3−, the major species were NH4+, Na+and Ca2+in Plum Rain, the secondary photochemical products SO42−, NO3−and NH4+in TOC Rain and Summer Rain, and Na+and Ca2+in Autumn–Winter Rain. Calculation of arithmetic means showed that dicarboxylic acids contributed between 0.25% and 0.53% of the total ionic concentration and of these, oxalic acid contributed the least (81.3% of the dicarboxylic acid) to TOC Rain and the most (96.1% of the dicarboxylic acid) to Spring Rain, suggestive of long-range transport in the latter. Differences in wet deposition composition were shown to be a result of differences in local emissions and long-range transport (hence of prevailing wind direction) during the period of rainfall and of the frequency and volume of rain that typifies each rainfall type. Principal component analysis (PCA) further revealed that traffic-related and industrial organic and inorganic pollutants, their secondary photochemical products, sea salts, and dust are important contributors to wet deposition. Moreover, the ratio of malonic acid to succinic acid (M:S ratio) indicated that both traffic and secondary photochemical reactions are major contributors to all but TOC Rain, for which the M:S ratio of 4.54 indicates a relative abundance of pollutants from secondary photochemical reactions. An ion balance (IB) ratio analysis demonstrated the validity of the results in this research.