VOCs走航观测在城市污染源排查中的应用

为推进城市空气质量精细化管理工作的实施,实现VOCs污染源精准排查,2019年3-4月,利用单光子电离飞行时间质谱对青岛市重点区域进行了VOCs走航观测。在排查到的污染源中,工业区的VOCs浓度较生活区整体偏高,且生活区、工业区夜间的VOCs浓度均较白天高。VOCs各类组分中,生活区白天苯系物、卤代烃、烯烃、烷烃的占比均在20%左右,夜间苯系物占比明显升高;工业区苯系物在白天和夜间的占比均最高,其他组分相对较小。浓度较高的前10位VOCs物种中,生活区白天烯烃物种占主导,夜间烷烃物种的比重明显增加;工业区苯系物、烯烃物种在白天和夜间的比重均较大,烷烃物种较小。生活区VOCs的污染源主要为机动车尾气排放和油品挥发,工业区主要为企业排放。烯烃和苯系物臭氧生成贡献较烷烃高,特别是丁烯、戊烯、己烯、甲苯、二甲苯/乙苯、三甲苯贡献显著,建议作为优控物种重点管控。

Application of VOCs Cruise Observation in Urban Pollution Sources Investigation

In order to promote the urban air quality refined management and investigate VOCs pollution sources accurately,the single-photon ionization time-of-flight mass spectrometry was used to monitor VOCs in key areas in Qingdao from March to April 2019. In the pollution sources identified,the VOCs concentration in the industrial area was higher than that in the living area,and the concentration was higher at night in both areas. The proportions of benzene homologues,halogenated hydrocarbons,olefins and alkanes in the living area were about 20% at daytime,and the proportion of benzene homologues increased significantly at night. The benzene homologues in the industrial area had the highest proportion both at daytime and night,and the other components were relatively lower. Among the top ten VOCs species with higher concentration in the living area,olefin species dominated at daytime,but the proportions of alkane species increased significantly at night. In the industrial area,the benzene homologues and olefin species had larger proportions at daytime and night,and the alkane species were smaller. The pollution sources of VOCs in the living area were mainly automobile exhaust emissions and oil volatilization,on the contrary,industrial emissions were the main sources in the industrial area. The contribution to ozone formation of olefins and benzene homologues were higher than that of alkanes,especially butene,pentene,hexene,toluene,xylene/ethylbenzene and trimethylbenzene,which were recommended to be preferred control species.