| Title: | Intermediate Volatility Organic Compound Emissions from On-Road Gasoline Vehicles and Small Off-Road Gasoline Engines |
| Author(s): | Zhao Y; Nguyen NT; Presto AA; Hennigan CJ; May AA; Robinson AL; |
| Address: | "Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States. Department of Mechanical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Dynamometer experiments were conducted to characterize the intermediate volatility organic compound (IVOC) emissions from a fleet of on-road gasoline vehicles and small off-road gasoline engines. IVOCs were quantified through gas chromatography/mass spectrometry analysis of adsorbent samples collected from a constant volume sampler. The dominant fraction (>80%, on average) of IVOCs could not be resolved on a molecular level. These unspeciated IVOCs were quantified as two chemical classes (unspeciated branched alkanes and cyclic compounds) in 11 retention-time-based bins. IVOC emission factors (mg kg-fuel(-1)) from on-road vehicles varied widely from vehicle to vehicle, but showed a general trend of lower emissions for newer vehicles that met more stringent emission standards. IVOC emission factors for 2-stroke off-road engines were substantially higher than 4-stroke off-road engines and on-road vehicles. Despite large variations in the magnitude of emissions, the IVOC volatility distribution and chemical characteristics were consistent across all tests and IVOC emissions were strongly correlated with nonmethane hydrocarbons (NMHCs), primary organic aerosol and speciated IVOCs. Although IVOC emissions only correspond to approximately 4% of NMHC emissions from on-road vehicles over the cold-start unified cycle, they are estimated to produce as much or more SOA than single-ring aromatics. Our results clearly demonstrate that IVOCs from gasoline engines are an important class of SOA precursors and provide observational constraints on IVOC emission factors and chemical composition to facilitate their inclusion into atmospheric chemistry models" |
| Keywords: | "Aerosols Alkanes/analysis California Gas Chromatography-Mass Spectrometry Gasoline/*analysis Models, Theoretical *Motor Vehicles Off-Road Motor Vehicles Vehicle Emissions/*analysis Volatile Organic Compounds/*analysis;" |
| Notes: | "MedlineZhao, Yunliang Nguyen, Ngoc T Presto, Albert A Hennigan, Christopher J May, Andrew A Robinson, Allen L eng Research Support, U.S. Gov't, Non-P.H.S. 2016/03/30 Environ Sci Technol. 2016 Apr 19; 50(8):4554-63. doi: 10.1021/acs.est.5b06247. Epub 2016 Apr 8" |
