南京北郊PM_(2.5)中含碳物质和水溶性离子的污染特性  

Characterization Apportionment of Carbonaceous Aerosol and Water-soluble Ions in PM_(2.5) at Suburban Nanjing

作　　者：王荔[1] 马嫣[1] 郑军[1] 王振[1] 周瑶瑶[1] 

机构地区：[1]南京信息工程大学环境科学与工程学院,南京210044

出　　处：《科学技术与工程》2015年第17期91-99,共9页Science Technology and Engineering

基　　金：国家自然科学基金(21377059;41275142;41030962);江苏省自然科学基金(BK2012861)资助

摘　　要：为了解南京市北郊四季细粒子中含碳组分与水溶性离子的污染特征及影响因素,于2012年8月～2013年6月期间在南京北郊采样点采集PM2.5样品.利用DRI Model 2001A热/光碳分析仪对有机碳（OC）与元素碳（EC）进行了测定.结果显示,PM2.5、OC、EC的质量浓度均是冬季最高、夏季最低,PM25的日平均值为122.7±75.2 μg/m3,OC和EC的日平均值分别为（15.4±8.0） μg/m3和（3.6±1.8） μg/m3,含碳物质占PM2.5总质量的11％ ～40％.OC与EC在秋季和冬季有较好的相关性（r2分别为0.86和0.83）,表明其来源相似;春季和夏季的相关性较低（r2分别为0.47和0.53）,可能原因是有较多二次有机碳（SOC）生成致其来源复杂.利用EC示踪法对SOC的含量进行了估算,夏季SOC占OC的比例最高,达到了44.6％,可见高温与强烈的光照有利于SOC的形成.利用戴安离子色谱对PM2.5中的阴离子SO42-、NO3-、F-、Cl-、HCOO-、CH3COO-和C2O42-,阳离子Na＋、NH4＋、K＋、Mg2＋、Ca2＋进行分析,结果表明,水溶性离子占PM2.5总质量的20％ ～ 60％,SO42-、NO3-、NH4＋二次离子是南京市郊PM2.5中主要的无机离子.PM25 aerosol samples were collected at suburban Nanjing from August 2012 to June 2013 to charac- terize and source-apportion their compositions of water-soluble ions and carbonaceous matter. The concentrations of organic carbon （OC） and elemental carbon （EC） were determined using DRI Model 2001A heat / light organic carbon analyzer. OC and EC＇ s daily averages values were 15.4±8.0μg/m3 and （3.6 ± 1. 8）μg/m3, respectively and the daily average of PM2.5 was （ 122. 7 ±75.2） μg/m3. The mass concentrations of PMzs, OC and EC were highest in winter and lowest in summer values. OC and EC showed a good correlation in the fall and winter （r2 = 0. 86 and O. 83 ）, indicating that they may originate from similar sources. However, low correlations （ r2 = 0. 47 and 0. 53 ） were found during spring and summer time, possibly due to strong but complicated SOC formation processes during these times of the year. Secondary organic carbon （SOC） content was estimated using the EC tracer meth- od. SOC to OC ratio was highest in summer, reaching 44. 6%, which was due to the high ambient temperatures and strong photochemical activity. Anions including SO4 2-, NO3-, F-, Br-, CI-, HCOO-, COO-, CH3COO- and cations including Na ＋, NHf, K＋, Mg2＋, Ca2＋ were analyzed using Dionex Ion Chromatography. The results showed that the proportion of water-soluble ions accounted for 20% - 60% of PM2. 5, Secondary ions, including SO]-, NO3-, NHf were the dominant inorganic ions in Nanjing suburban area. Water-soluble ions and carbonaceous material were major components of atmospheric particles in northern suburb of Nanjing, accounting for over 50% of PM2.5.

关 键 词：气溶胶 南京北郊 有机碳 元素碳 水溶性离子 

分 类 号：X513[环境科学与工程—环境工程]