天津市机动车二次有机气溶胶生成潜势的估算

通过隧道实验得到天津市机动车排放的挥发性有机物(VOCs)的物种信息及各物种的浓度数据,检测得到88种VOCs,其中23种VOCs具有二次有机气溶胶(SOA)生成潜势.基于天津市机动车尾气挥发性有机污染物的监测数据,利用气溶胶生成系数(FAC)对天津市机动车排放VOCs的二次有机气溶胶生成潜势进行了估算.结果表明,邻-二甲苯、甲苯、苯、间-二甲苯、对-二甲苯、对-二乙苯是对SOA生成贡献最大的6个物种,各自SOA生成量分别为973.97,721.05,687.31,592.09,571.31,538.59t/a,分别占SOA生成潜势的13.87%、10.27%、9.79%、8.43%、8.13%、7.67%;芳香烃是对SOA生成贡献最大的前体物,其SOA生成量占SOA生成潜势的88.95%.因此,减少机动车芳香烃类物质的排放,可有效地减少SOA的生成量.

Estimate of vehicles generation of secondary organic aerosols of Tianjin

We obtained the species information of vehicle exhaust of Tianjin and the concentration data of each species through the tunnel experiment. Among the 88kinds of VOCs we have monitored, there are 23 kinds of VOCs have potential to generate SOA. We estimated secondary organic aerosols (SOA) generation potential with fractional aerosol coefficients (FAC) based on the monitored data of volatile organic compounds (VOCs) in the vehicles exhaust of Tianjin. The results show that o-xylene, toluene, benzene, m-xylene, p-xylene and p-diethylbenzene have the largest production accounted for 13.8%, 10.22%, 9.74%, 8.39%, 8.10%, 7.64% of total SOA, respectively. In among of the vehicles exhaust, aromatics are considered to be the biggest contributors to the SOA, accounting for 88.95% of the total SOA. Therefore, the key to reduce the quantity of SOA is to control the emissions of aromatic hydrocarbons.