汕头市挥发性有机物变化特征及O3污染成因研判

Study on the changing characteristics of volatile organic compounds and the cause of O3 pollution in Shantou City

采用全自动气相色谱(GC)/火焰离子化检测器(FID)方法对汕头市大气挥发性有机污染物(VOCs)进行了为期1个月的在线实时观测,分析了VOCs的变化特征及其O 3生成潜势(OFP),并结合基于观测的模型对O 3污染成因进行了探析。研究结果表明:(1)汕头市的VOCs均值为1.91×10-8(以大气中体积分数计),其中烷烃类占比最高,为64.4%,甲苯、苯质量比(T/B)为3.34,表明气团除受机动车尾气影响外,还受到其他污染源影响;(2)芳香烃和烯烃是大气VOCs中对OFP贡献最大的组分;(3)观测期间,在前期O 3残留(贡献率19.9%)、局部O 3生成(贡献率40.8%)以及区域传输(贡献率39.3%)共同作用下,O 3出现轻度污染。

A full-automatic GC-FID method was used to conduct a one-month online real-time observation of atmospheric volatile organic compounds(VOCs)in Shantou City.The changing characteristics of VOCs and their O 3 generation potential(OFP)were analyzed,and the cause of O 3 pollution was analyzed in combination with the observation based model.The results showed that:(1)the average volume fraction of VOCs in Shantou City was 1.91×10-8,and alkanes accounted for the highest proportion,which was 64.4%.The toluene and benzene mass ratio(T/B)was calculated as 3.34,indicating that the air was affected by other pollution sources in addition to the vehicle exhaust;(2)aromatic hydrocarbons and olefins contributed the most to OFP in atmospheric VOCs;(3)during the observation period,under the influence of the previous O 3(contribution of 19.9%),the locally generated O 3(contribution of 40.8%)and the regional transmission effect(contribution of 39.3%),the air was slightly polluted.