成都市城区环境大气中典型特征VOCs示踪物种分析

VOCs排放来源较多且成分复杂,通过某些特征物种的浓度比值可以获得相应的VOCs来源信息,2018年12月至2019年11月使用TH-300B大气挥发性有机物快速在线监测系统在成都市内进行监测,并用比值法对VOCs的示踪物种进行分析,研究表明,在监测时间范围内,乙烷、丙烷、正戊烷、异戊烷、异戊二烯、乙炔、苯、甲苯、乙苯、间(对)二甲苯的平均浓度分别为5.49ppb、3.60ppb、0.54ppb、1.14ppb、0.1ppb、3.87ppb、0.53ppb、0.87ppb、0.25ppb和0.87ppb;甲苯/苯和异戊烷/正戊烷的比值分别为1.17和1.67,表明市区VOCs的排放受机动车尾气影响较为显著,需继续加强机动车的管控;对二甲苯/乙苯和苯/甲苯的比值分别为3.7和0.85,市区气团有一定老化,春季和冬季气团老化程度较大,光化学年龄较长。

Analysis on Tracer Species of Typical Characteristic VOCs in Urban Environment Atmosphere of Chengdu

VOCs emissions come from many sources with complex components,and the corresponding VOCs source information can be obtained through the concentration ratio of some characteristic species.From December 2018 to November 2019,the TH-300 B rapid online monitoring system for atmospheric volatile organic compounds was used to monitor in Chengdu,and the tracer species of VOCs were analyzed by the ratio method.The research showed that during the monitoring period,the average concentrations of ethane,propane,n-pentane,isopentane,isoprene,acetylene,benzene,toluene,ethylbenzene,m-p-xylene were 5.49 ppb,3.60 ppb,0.54 ppb,1.14 ppb,0.1 ppb,3.87 ppb,0.53 ppb,0.87 ppb,0.25 ppb,and 0.87 ppb.The ratios of toluene/benzene and isopentane/n-pentane were 1.17 and 1.67,respectively,indicating that the emissions of VOCs in urban areas were significantly affected by vehicle exhaust.It is necessary to continue to strengthen the control of motor vehicles.The ratios of p-xylene/ethylbenzene and benzene/toluene were 3.7 and 0.85,respectively.The urban air masses is aging to a certain extent.The aging degree of air mass is greater in spring and winter,and the photochemical age is longer.