中文摘要：

机动车源排放颗粒物是城市大气PM_（2.5）的重要来源之一。气溶胶质谱提供的高分辨数据为有机气溶胶的源解析提供了有力支持,但由于缺乏机动车源排放颗粒物的源谱信息,目前仍无法实现对于机动车源贡献的准确解析。研究基于整车转鼓实验,利用气溶胶质谱测量了进气道喷射汽油车直接排放有机颗粒物的高分辨率源谱。汽油车直接排放有机物主要由C_xH_y~＋碎片构成,可能来自于未完全燃烧的燃料和润滑油的裂解。源谱的离子碎片比例及氧碳比特征受到发动机状态影响。热起动状态下,一次颗粒物受到汽油燃烧产物的影响相对较大,具有较高氧碳比。将实验测得源谱与实际大气HOA谱图进行比对表明,HOA与机动车直接排放颗粒物不完全相同,因此HOA不能准确代表机动车一次排放贡献。

英文摘要：

Primary emissions from vehicles contribute significantly to urban PM_（2.5） pollution. The high resolution mass spectra（MS） provided by Aerosol Mass Spectrometry（AMS） has proved to be a useful dataset for source apportionment of organic aerosols（OA）. However, the lack of source profiles of vehicle emission results in the large uncertainty in the source apportionment of traffic related sources. Vehicle chassis dynamometer tests were conducted to investigate reference spectra of primary emissions from gasoline vehicle with PFI engine. The most dominant fragments in the spectra are C_xH_y~＋ ions, which may be derived from fragmentation of fuel and lubricating oil of incomplete combustion. The relative contribution of different fragments as well as O/C ratio are influenced by engine condition. During the hot start, the primary aerosol are greater influenced by combustion-derived OA, which have a higher O/C ratio. The reference spectra of primary emission from gasoline vehicle were further compared with hydrocarbon like OA（HOA） resolved from ambient air. Their differences imply HOA cannot be considered as a surrogate of traffic related primary emission.