摘要
在南京市六个典型点位,于2014~2015年的四个季节,开展了PM_(2.5)化学组分的监测.基于513个有效样本资料,分析了包括硫酸根(SO_4^(2-))、硝酸根(NO_3^-)、铵根(NH_4^+)和二次有机物(SOA)的二次组分的时空分布特征.结果表明:南京市PM_(2.5)以二次组分为主,约占57.7%,其中SO_4^(2-)、NO_3^-、NH_4^+和SOA年均浓度分别为11.9,12.5,7.7,8.7μg/m^3,所占PM_(2.5)的比例分别是17.2%、16.9%、10.5%、13.1%,其中98.8%的SO_4^(2-)为非海盐成分;近年来,[NO_3^-]/[SO_4^(2-)]快速增加,2015年约达到1.0,表明机动车的贡献日益突出;南京市二次组分季节差异较显著,NO_3^-、NH_4^+和SOA占比秋冬季节大于春夏季节,SO_4^(2-)占比春夏季节大于秋冬季节;空间分布上,二次组分的占比在远郊区最高(73.5%),其次是近郊新城区(59.0%),城市中心区和工业区最小(57.3%,57.4%),这反映了不同区域PM_(2.5)来源的差异;随着污染水平的上升,NO_3^-的占比显著增加,这表明机动车对于重污染过程具有更加重要的影响.研究结果深化了关于南京PM_(2.5)来源的认识,可以为更有效地控制灰霾污染提供科学依据.
Secondary components are important composition of PM2.5,mainly including SO42-,NO3-,NH4+and SOA.513PM2.5samples were collected at six sampling sites in Nanjing during four seasons from October2014to August2015.Based on the chemical compositions,temporal and spatial characteristics of secondary components of PM2.5in Nanjing were analyzed.On averagely,the secondary components accounted for about57.7%of the PM2.5mass concentration.Concentrations of SO42-,NO3-,NH4+and SOA were11.9,12.5,7.7and8.7μg/m3,with proportions of17.2%,16.9%,10.5%and13.1%,respectively,and98.8%of SO42-was non-sea-salt-originated.The value of[NO3-]/[SO42-]had been increasing rapidly in recent yearsand reached about1.0in2015,suggesting that vehicle pollution hasbeen aggravated in Nanjing.The contents of NO3-,NH4+and SOA in Nanjing werehigh in autumnand winter,lower in spring and summer,but SO42-shows the opposite trend.Proportion of secondary componentswasthe highest(73.5%)in the outer suburb of the city,followed by suburb regions(59.0%),and lowest in city center and industrial region(57.3%,57.4%),reflecting different sources in different regions.Proportions of NO3-kept steadily increasing with PM2.5concentrations rise,suggestingvehicle pollution may play a more important role in heavy haze pollution episodes.This study contributes to deepen understanding of the sources of PM2.5in Nanjing,and provides a scientific basis for the haze pollution control.
作者
卫菲菲
刘昊
陆晓波
王勤耕
葛颖
郝娇
WEI Fei-fei;LIU Hao;LU Xiao-bo;WANG Qin-geng;GE Ying;HAO Jiao(School of the Environment, Nanjing University, Nanjing 210023,China;Nanjing Municipal Environment Monitoring Station, Nanjing 210024, China;Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science & Technology, Nanjing 210044, China)
出处
《中国环境科学》
EI
CAS
CSSCI
CSCD
北大核心
2017年第8期2866-2876,共11页
China Environmental Science
基金
国家重点研发计划(2016YFC0208504)
973计划(2014CB441203)
江苏省科技支撑项目(BE2014602)
关键词
PM2.5
二次气溶胶
灰霾
时空分布
南京
PM2.5
secondary aerosols
haze
temporal and spatial characteristics
Nanjing
