轻型汽油车VOCs排放特征及其大气反应活性

Emission characteristics and chemical reactivity of volatile organic compounds from light-duty gasoline vehicles

采用车载式尾气测量系统对国Ⅱ、国Ⅲ、国Ⅳ轻型汽油车在实际道路排放的尾气进行样品采集,并采用GC-MS、GC-FID对尾气中烷烃、烯烃、苯系物进行测试分析.结果表明轻型汽油车的VOCs排放因子随排放标准的提高显著降低,国Ⅱ、国Ⅲ、国Ⅳ3种车型的排放因子分别为49.62、21.65、6.72mg/km.苯系物占测定VOCs组分的比例最高,占到总VOCs的47.43%-60.52%.由排放的VOCs估算获得不同标准车型的臭氧生成潜势及二次有机气溶胶生成潜势分别为24.64-234.14mg/km和13.24-125.32mg/km.在对国Ⅲ车型进行的不同速度的实验结果显示,轻型汽油车尾气VOCs排放因子及相应的臭氧生成潜势和二次有机气溶胶生成潜势均随实验车速的升高而降低.

The VOCs samples emitted from light-duty gasoline vehicles ranging from China Ⅱ to China Ⅳ was collected by portableemission measurement system（PEMS）. Alkanes, alkenes and aromatics in the exhaust were analyzed using GC-MS and GC-FID. Results demonstrated that the emission reductions of VOCs from light-duty gasoline vehicles had been achieved as the control technology become more rigorous, China Ⅱ, China Ⅲ and China Ⅳ vehicles were 49.62, 21.65 and 6.72mg/km, respectively. Aromatics were the dominant VOCs with weight percentages of 47.43%-60.52%. The ozone formation potentials and SOA formation potential for different emission standards were 24.64 - 234.14mg/km and 13.24 -125.32mg/km. Driving speeds also influenced the VOCs emissions from the tested China Ⅲ vehicles, the VOCs emission factors, ozone formation potential（OFP） and SOA formation potential from light-duty gasoline vehicles were dropped with the increase of the speed.