基于走航监测的城市VOCs污染特征分析

Urban VOCs pollution characteristics based on cruise monitoring

2021年9月01日-9月29日利用飞行时间质谱在安庆市重点区域进行了VOCs走航监测,对VOCs污染特征进行了分析。结果表明:走航监测期间TVOC平均浓度为286.8μg/m~3,夜间TVOC平均浓度整体高于日间,是日间浓度的2.64倍。走航监测共发现45个高值点,其中41个高值点位于高新区,涵盖了14个相关企业。走航车在高值点进行了驻点监测,筛选出VOCs特征因子。走航期间VOCs各类组分占比依次为芳香烃(31.7%)、烷烃(30.4%)、卤代烃(13.7%)、烯烃(11.3%)、含氧含氮烃(11.2%)及有机硫(1.7%)。排名前十的VOCs物种中,正庚烷、甲苯及正辛烷位居前三。各类VOCs物种对OFP的贡献由大到小依次为芳香烃(53.3%)、烯烃(33.6%)、烷烃(11.5%)及卤代烃(1.5%),芳香烃和烯烃对臭氧生成贡献较高,建议将丁烯、甲苯、萘、三甲苯、二乙基苯及戊烯作为安庆市防治臭氧污染的关键物种,减少臭氧污染,为打赢蓝天保卫战提供有力保障。

The Time-of-flight mass spectrometry was used to carry out VOCs cruise monitoring in key areas in Anqing from September 1 th to 29 st, 2021, and the characteristics of VOCs pollution were analyzed. The results showed that: during the cruise monitoring period, the average concentration of TVOC was 286.8μg/m~3, the average concentration of TVOC at night was generally higher than that during the day, the TVOC level at night was 2.64 times that of the day time. A total of 45 high-value points were found during the cruise monitoring, of which 41 were located in the high-tech zone having 14 related companies. The cruise vehicle carried out stationary monitoring at high value points, and screened out the characteristic factors of VOCs. During the cruise monitoring period, the proportions of various components of VOCs were in the order of aromatic hydrocarbons(31.7%), alkanes(30.4%), halogenated hydrocarbons(13.7%), olefins(11.3%), oxygen-containing nitrogen-containing hydrocarbons(11.2%) and organic sulfur(1.7%). Among the top ten VOCs species, n-heptane, toluene and n-octane were the top three. The contribution of various VOCs to OFP in descending order was aromatic hydrocarbons(53.3%), olefins(33.6%), alkanes(11.5%) and halogenated hydrocarbons(1.5%). Aromatic hydrocarbon and olefins had higher contribution rate to ozone generation. Butene, toluene, naphthalene, trimethyl benzene, diethyl benzene and pentene were recommended as the key species for preventing ozone pollution in Anqing, so as to reduce ozone pollution and protect the blue sky.