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The effects of operating conditions on semivolatile organic compounds emitted from light-duty, gasoline-powered motor vehicles
Citation:
HERRINGTON, J. S., M. D. HAYS, B. J. GEORGE, AND R. W. BALDAUF. The effects of operating conditions on semivolatile organic compounds emitted from light-duty, gasoline-powered motor vehicles. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 54:53-59, (2012).
Impact/Purpose:
journal article
Description:
A thermal extraction-gas chromatography-mass spectrometry (TE-GC-MS) method was used to quantitatively examine organic compounds in fine particulate matter (PM2.5) 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 study applied the LA92 Unified Driving Cycle (UDC), consisting of “cold start”, “hot stabilized running”, and “warm start” phases. The sensitivity of the TE-GC-MS analysis provided the opportunity to examine the emission rates and proportions of organic compounds [including polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes] on a vehicle-by-vehicle and phase-by-phase basis. Vehicles tested in both summer and winter provided data on ambient temperature effects. Results indicated that operating conditions significantly affected PM2.5 organic compound emission rates and proportions. The mean emission rates for all target compounds for the cold start, hot stabilized running, and warm start phases were 8.07, 0.45, and 1.02 µg/mile, respectively. Statistical analyses indicated the cold start phase emission rates were significantly higher than the hot stabilized running and warm start phases for 89% of the target compounds. Results also indicated that emission rates were significantly higher in the winter for 92% of the target compounds. An increase in organic compound proportions in PM2.5 during the warm start phase relative to the cold start and hot stabilized running phase was an important finding. This observation was significant for 31% of the target compounds, including chrysene, benzo[a]anthracene, and pyrene. Observations of organic compound emissions from motor vehicles have been little reported by previous studies and may have important implications for emissions modeling, source apportionment studies, and human exposure assessments.
