兰州市低碳数正构烷烃组分特征及大气化学反应活性分析  

Characteristics and Atmospheric Chemical Reaction Activity of Low Carbon Number Normal Alkanes in Lanzhou City

作　　者：齐安安 周小平 马鑫 雷春妮 庞伟强 管贤贤 QI An′an;ZHOU Xiaoping;MA Xin;LEI Chunni;PANG Weiqiang;GUAN Xianxian(College of Geography and Environment Science,Northwest Normal University,Lanzhou 730070,China;Lanzhou Customs Technology Center,Lanzhou 730010,China;Institute of Earth Environment,Chinese Academy of Sciences,Xi′an 710061,China)

机构地区：[1]西北师范大学地理与环境科学学院,甘肃兰州730070 [2]兰州海关技术中心,甘肃兰州730010 [3]中国科学院地球环境研究所,陕西西安710061

出　　处：《环境科学研究》2020年第2期296-304,共9页Research of Environmental Sciences

基　　金：质检科技重大专项(No.2018IK059,2017GK002)~~

摘　　要：为明确兰州市大气环境常态下低碳数正构烷烃(C5~C19)质量浓度变化、组分特征及大气化学反应活性之间的关系,于2017年11月—2018年6月选取兰州市5个采样点,利用TENAX吸附管采集空气样品,应用TD-GC/MS(热脱附-气质联用)法对样品进行分析.对空气样品中低碳数正构烷烃大气化学反应活性的OFP(臭氧生成潜势)、·OH消耗速率、SOA(二次有机气溶胶)生成潜势进行评估计算,通过相关性分析及因子分析法分析低碳数正构烷烃的大气化学反应活性贡献率特征.结果表明:①在10种低碳数正构烷烃中,正己烷(C6)对OFP的贡献率最大,正辛烷(C8)对·OH消耗速率的贡献率最大,二者的贡献率分别为37.71%和37.64%.②在10种低碳数正构烷烃中正辛烷(C8)对SOA生成潜势的贡献率最大,为50.02%.③大气化学反应活性参数相关性分析表明,低碳数正构烷烃总质量浓度与OFP、·OH消耗速率相关性显著(R分别为0.895和0.948).④因子分析表明,5个未知因子所包含的化学反应活性信息量在94.511%以上,所含信息量也体现了未知因子组成的重要性,可为进一步解析大气化学反应活性提供参考.研究显示,正辛烷、正己烷是低碳数正构烷烃的2个关键活性组分,正辛烷是大气化学反应活性贡献率最大的化合物之一,也是汽车尾气排放源的主要组成部分,正己烷是人为源与自然源的混合产物.In order to investigate the mass concentrations,the component characteristics and the atmospheric chemical reactivityof low-carbon n-alkanes in Lanzhou City,samples were collected by TENAX adsorption tube from November 2017 to June 2018 at five sampling points.The low carbon number normal n-alkanes in air samples were analyzed by thermal desorption-gas chromatography massspectrometry(TD-GC MS).The atmospheric chemical reactivity of low carbon number normal n-alkanes,including ozone generation potential,·OH consumption rate,and secondary organic aerosol generation potential,was evaluated.The characteristics of atmospheric reactivity contribution of the low carbon number normal n-alkanes were analyzed by the correlation analysis and factor analysis.The results showed that in the 10 low carbon normal n-alkanes,the contribution rate of n-hexane(C6)to OFP and the contribution rate of n-octane(C8)to·OH consumption rate are the largest,and the contribution ratios were 37.71%and 37.64%.n-octane(C 8)has a large contribution rate to SOA formation(50.02%)in 10 low carbon number normal alkanes.The total mass concentration of the low carbon n-alkanes was significantly correlated with ozone generation potential(R=0.985)and OH radical consumption rate(R=0.948).Five unknown factors explained more than 94.511%of the chemical reactivity information by factor analysis,the amount of information contained also reflects the importance of unknown factors,which can provide a reference for further analysis of atmospheric chemical reactivity.The study shows that n-octane and n-hexane are the two key active components of the measured low carbon number normal n-alkanes(between C 5-C 19);n-octane is one of the compounds with the highest contribution to atmospheric chemical reactivity,and it is derived fromthe exhaust emissions ofautomobiles;N-hexane is a mixture of anthropogenic and natural sources.

关 键 词：兰州市 低碳数正构烷烃 组分特征 化学反应活性 

分 类 号：X511[环境科学与工程—环境工程]