2015~2019年南京北郊碳质气溶胶组成变化  

Changes in Carbonaceous Aerosol in the Northern Suburbs of Nanjing from 2015 to 2019

作　　者：谢添 曹芳 章炎麟[1,2] 林煜棋 范美益[1,2] 宋文怀 鲍孟盈 项妍琨 赵祝钰 杨笑影 谢锋 张煜娴 俞浩然 张子金 邢佳莉 XIE Tian;CAO Fang;ZHANG Yan-lin;LIN Yu-chi;FAN Mei-yi;SONG Wen-huai;BAO Meng-ying;XIANG Yan-kun;ZHAO Zhu-yu;YANG Xiao-ying;XIE Feng;ZHANG Yu-xian;YU Hao-ran;ZHANG Zi-jin;XING Jia-li(International Joint Laboratory on Climate and Environment Change(ILCEC),Yale-NUIST Center on Atmospheric Environment,School of Applied Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,China;Key Laboratory of Meteorological Disaster,Ministry of Education(KLME),Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Nanjing University of Information Science&Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学应用气象学院,耶鲁大学-南京信息工程大学大气环境中心,气候与环境变化国际合作联合实验室,南京210044 [2]南京信息工程大学气象灾害预报预警与评估协同创新中心,气象灾害教育部重点实验室,南京210044

出　　处：《环境科学》2022年第6期2858-2866,共9页Environmental Science

基　　金：国家自然科学基金项目(41977305,41977185);江苏省自然科学杰出青年基金项目(BK20180040);江苏省“333人才计划”项目(RRA20200)。

摘　　要：碳质气溶胶是大气细颗粒物的重要组成,对空气质量、人体健康和气候变化有着重要影响.为了探究碳质气溶胶在减排背景下的长期变化,本研究测定了南京北郊5 a(2014年12月17日至2020年1月5日)PM_(2.5)样品的有机碳(OC)和元素碳(EC)浓度.结果表明,ρ(OC)和ρ(EC)5a平均值分别为(10.2±5.3)μg·m^(-3)和(1.6±1.1)μg·m^(-3),其中OC占PM_(2.5)的31.1%,EC占PM_(2.5)的5.2%.OC和EC均呈现出冬高夏低的季节特征.通过非参数的Mann-Kendall检验和Sen's斜率发现,OC和PM_(2.5)的浓度整体呈显著下降趋势[OC:P<0.0001,-0.79μg·(m^(3)·a)^(-1),-0.29%·a^(-1);PM_(2.5):P<0.0001,-4.59μg·(m^(3)·a)^(-1),-1.58%·a^(-1)].EC虽然整体上升,但显著性和变化幅度相对而言并不明显[P=0.02;0.05μg·(m^(3)·a)^(-1),0.02%·a^(-1)].从冬季的长期变化看,OC、EC都呈显著下降[OC:P<0.0001,-2.05μg·(m^(3)·a)-1,-0.74%·a^(-1);EC:P=0.001,-0.15μg·(m^(3)·a)^(-1),-0.05%·a^(-1)],且下降较总体更明显.OC和EC的相关性表明,冬季和夏季的来源较春季和秋季更复杂.根据OC/EC特征比值判断,2015~2019年燃煤源和生物质燃烧源的贡献有所下降,工业源与机动车排放源的影响日益显著,与此对应的是OC的明显下降和EC的轻微回升.OC/EC比值大于2.0,说明研究区域存在二次污染.进一步计算发现SOC变化与OC一致,呈显著下降[P<0.0001,-0.47μg·(m^(3)·a)^(-1),-0.17%·a^(-1)],均值为(5.0±3.5)μg·m^(-3),占OC的49.2%.以上变化说明南京市近年来对空气污染的防控治理效果明显,同时今后的治理可以针对VOCs的排放,以减轻二次污染.Carbonaceous aerosol is an important component of atmospheric fine particles that has an important impact on air quality,human health,and climate change.In order to explore the long-term changes in carbonaceous aerosol under the background of emission reduction,this study measured the mass concentrations of organic carbon(OC)and elemental carbon(EC)of PM_(2.5),which collected in the northern suburbs of Nanjing for five years(December 17,2014 to January 5,2020).The results showed that the five-year averageρ(OC)andρ(EC)were(10.2±5.3)μg·m^(-3)and(1.6±1.1)μg·m^(-3),accounting for 31.1%and 5.2%of PM_(2.5),respectively.OC and EC concentrations were both high in winter and low in summer.According to the nonparametric Mann-Kendall test and Sen's slope,the mass concentrations of OC and PM_(2.5)decreased significantly[OC:P<0.0001,-0.79μg·(m^(3)·a)^(-1),-0.29%·a^(-1);PM_(2.5):P<0.0001,-4.59μg·(m^(3)·a)^(-1),-1.58%·a^(-1)].Although EC had an upward trend,the significance and range of change were not obvious[P=0.02,0.05μg·(m^(3)·a)^(-1),0.02%·a^(-1)].OC and EC decreased significantly during winter from 2014 to 2019[OC:P<0.0001,-2.05μg·(m^(3)·a)^(-1),-0.74%·a^(-1);EC:P=0.001,-0.15μg·(m^(3)·a)^(-1),-0.05%·a^(-1)],and the decline was more obvious than the whole.The correlation between OC and EC showed that the sources in winter and summer were more complex than those in spring and autumn.According to the characteristic ratio of OC and EC,the contribution of coal combustion and biomass burning decreased from 2015 to 2019,whereas the impact of industrial sources and vehicle emissions became more significant.Corresponding to this was the obvious decline in OC and the slight recovery of EC.The OC/EC ratio was over 2.0,indicating that there was secondary pollution in the study area.Further calculation revealed that the variation in SOC was consistent with that in OC,showing a significant decrease[P<0.0001,-0.47μg·(m^(3)·a)^(-1),-0.17%·a^(-1)].The average mass concentration of SOC was(5.0±3.5)μg·m^(-

关 键 词：南京北郊 有机碳(OC) 元素碳(EC) 长期变化 二次有机碳(SOC) 

分 类 号：X513[环境科学与工程—环境工程]