The ion chemistry and the source of PM2.5 aerosol in Beijing
The ion chemistry and the source of PM2.5 aerosol in Beijing
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DOI：
10.1016/j.atmosenv.2005.03.013
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发表时间：
2005-07-01
影响因子：
5
通讯作者：
Zheng, AH
中科院分区：
文献类型：
--
作者：
Wang, Y;Zhuang, GS;Zheng, AH
从2001年到2003年，在北京的五个采样点采集了三年的PM2.5气溶胶样本。测定了334个样品中的水溶性离子(SO42-、NO3-、Cl-、F-、PO43-、NO2-、CH3COO-、HCOO-、MSA、C2O42-、NH4+、Ca2+、K+、Mg2+、Na+)和23种元素的含量。整个北京的空间分布相对均匀，季节变化明显。气溶胶颗粒中主要离子为SO42-、NO3-、Cl-、NH4+、Ca2+和K+，主要以(NH4)(2)SO4、NH4NO3、氯化钠、氯化钾和氯化钙的形式存在。大多数离子冬季浓度较高，夏季浓度较低。由于夏季高湿度和强太阳辐射加速了二次离子的转化，以及燃煤产生的SO2浓度较高，冬季SO42-、NO3-的去除速率较低，因此夏季和冬季的二次离子浓度都较高，主要是SO42-、NO3-。SO42-和NO3-的生成分别主要受温度和NH4+的影响。温度、相对湿度、雨水频率和气团来源可能是影响气溶胶分布的主要因素。春季，由于中国西侧和西北部的沙尘侵入，地壳离子呈现零星的高峰期。用Ca~(2+)/Al比值来指示不同粉尘来源的混合。因子分析表明，煤/生物质燃烧产物的二次生成、结壳、工业排放和交通排放是北京市细颗粒气溶胶的主要来源。近年来，随着机动化的推进，交通来源变得更加重要。(C)2005爱思唯尔有限公司。保留所有权利。
Daily PM2.5 aerosol samples were collected at five sites in Beijing for a 3-year period from 2001 to 2003. Concentrations of the water-soluble ions (SO42-, NO3-, Cl-, F-,PO43-, NO2-, CH3COO-, HCOO-, MSA, C2O42-, NH4+, Ca2+, K+, Mg2+, Na+) and 23 elements were measured for a total of 334 samples. A relatively even spatial distribution throughout Beijing and a significant seasonal variation were observed. SO42-, NO3-, Cl-, NH4+, Ca2+, and K+ were the major ions and existed mainly in the form of (NH4)(2)SO4, NH4NO3, NaCl, KCI, and CaCl2 in aerosol particles. Most ions showed high concentrations in winter and low in summer. Secondary ions, mainly SO42-, NO3-, exhibited high concentrations in both summer and winter due to the secondary transformation accelerated under high humidity and strong solar radiation in summer and the higher concentration of SO2 from coal burning and the lower removal rate in winter. The formations SO42- and NO3- were determined largely by temperature and NH4+, respectively. Temperature, relative humidity, rainwater frequency, and air mass origin might be the main factors regulating the aerosol distribution. Crustal ions exhibited sporadic but high peaks in spring due to the intrusion of dust from west and northwest of China. The Ca2+/Al ratio was used to indicate the mixing of different dust sources. Factor analysis showed that the secondary formation of coal/biomass burning products, crust, industrial and traffic emissions were the major sources of the fine aerosols in Beijing. Traffic source became more significant with motorization in recent years. (c) 2005 Elsevier Ltd. All rights reserved.