The effects of operating conditions on semivolatile organic compounds emitted from light-duty, gasoline-powered motor vehicles

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• 作者：Jason S. Herrington^a ; Michael D. Hays^a ; ^{hays.michael@epa.gov} ; Barbara J. George^b ; Richard W. Baldauf^a ; ^c
• 关键词：Particulate matter ; Motor vehicle emissions ; Thermal extraction ; Organic PM ; Vehicle operating conditions
• 刊名：Atmospheric Environment
• 出版年：2012
• 期刊代码：11_13522310
• 类别：env
• 出版时间：July, 2012
• 卷：54
• 期：Complete
• 页码：53-59
• 文件大小：433 K

摘要

A thermal extraction-gas chromatography-mass spectrometry (TE-GC-MS) method was utilized to quantitatively examine semivolatile organic compounds (SVOCs) in fine particulate matter (PM_2.5) collected from light-duty, gasoline-powered vehicle (LDGV) exhaust. Emissions were analyzed from a subset of 18 vehicles tested in the Kansas City Light-Duty Vehicle Emissions Study (KCVES). The KCVES applied the LA92 Unified Driving Cycle (UDC), consisting of 鈥渃old start鈥? 鈥渉ot stabilized running鈥? and 鈥渨arm start鈥?phases. The sensitivity of the TE-GC-MS analysis provided the opportunity to examine the emission rates and proportions of SVOCs (including polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes) in PM_2.5 on an individual vehicle basis for each UDC phase. Mean target SVOC emissions rates of 5.01 渭g km^鈭?, 0.28 渭g km^鈭?, and 0.63 渭g km^鈭? were reported for the cold start, hot stabilized running, and warm start phases, respectively. Operating conditions as depicted by each UDC phase significantly affected SVOC emission rates and proportions in PM_2.5. The cold start phase emission rates were significantly higher than the hot stabilized running and warm start phases for 89%of the target SVOCs. An increase in SVOC proportions in PM_2.5 was observed during the warm start phase compared with the cold start and hot stabilized running phase. This observation was significant for 31%of the target compounds, including chrysene, benzo[a]anthracene, and pyrene. Vehicles tested in both summer and winter provided emissions data describing ambient temperature effects. Emission rates were significantly higher in the winter for 92%of the target SVOCs. Until now, observations of specific SVOCs in motor vehicle emissions produced under changing operating conditions were scant. Such emissions data may be useful for emissions modeling, source apportionment studies, and human exposure assessments.