Lubricating Oil Dominates Primary Organic Aerosol Emissions from Motor Vehicles
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- 作者：David R. Worton ; Gabriel Isaacman ; Drew R. Gentner ; Timothy R. Dallmann ; Arthur W. H. Chan ; Christopher Ruehl ; Thomas W. Kirchstetter ; Kevin R. Wilson ; Robert A. Harley ; Allen H. Goldstein
- 刊名：Environmental Science & Technology
- 出版年：2014
- 出版时间：April 1, 2014
- 年：2014
- 卷：48
- 期：7
- 页码：3698-3706
- 全文大小：387K
- 年卷期：v.48,no.7(April 1, 2014)
- ISSN：1520-5851
文摘
Motor vehicles are major sources of primary organic aerosol (POA), which is a mixture of a large number of organic compounds that have not been comprehensively characterized. In this work, we apply a recently developed gas chromatography mass spectrometry approach utilizing 鈥渟oft鈥?vacuum ultraviolet photoionization to achieve unprecedented chemical characterization of motor vehicle POA emissions in a roadway tunnel with a mass closure of >60%. The observed POA was characterized by number of carbon atoms (NC), number of double bond equivalents (NDBE) and degree of molecular branching. Vehicular POA was observed to predominantly contain cycloalkanes with one or more rings and one or more branched alkyl side chains (鈮?0%) with low abundances of n-alkanes and aromatics (<5%), similar to 鈥渇resh鈥?lubricating oil. The gas chromatography retention time data indicates that the cycloalkane ring structures are most likely dominated by cyclohexane and cyclopentane rings and not larger cycloalkanes. High molecular weight combustion byproducts, that is, alkenes, oxygenates, and aromatics, were not present in significant amounts. The observed carbon number and chemical composition of motor vehicle POA was consistent with lubricating oil being the dominant source from both gasoline and diesel-powered vehicles, with an additional smaller contribution from unburned diesel fuel and a negligible contribution from unburned gasoline.