AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Emissions of Intermediate-volatility Organic Compounds from On-road Vehicles
YUNLIANG ZHAO, Ngoc Nguyen, Albert A. Presto, Andrew May, Christopher Hennigan, Allen Robinson, Carnegie Mellon University
Abstract Number: 371 Working Group: Combustion
Abstract Intermediate-volatility organic compounds (IVOCs) emitted from primary sources have been indicated to contribute significantly to secondary organic aerosol formation by chamber experiments, field measurements and SOA models. However, the importance of IVOCs in the atmosphere is poorly understood due to the lack of measurements of IVOCs in both the atmosphere and emissions. In this study, emission factors and volatility distribution of IVOCs were characterized in tailpipe emissions from in-use, on-road vehicles at the California Air Resources Board Haag-Smit and Heavy-Duty Engine Testing Laboratories. The test fleet was composed of 47 light duty gasoline vehicles, 5 diesel trucks. Control technologies can significantly reduce emissions of IVOCs. The emission factors of IVOCs are found to strongly correlated to emissions factors of non-methane organic gases (NMOG) and primary organic aerosol (POA). The strong correlation indicates that IVOC emissions can be well predicted based data of NMOG and POA in the emission inventory. The volatility distributions of IVOCs emitted from on-road gasoline vehicles are different from those from diesel vehicles, but they exhibit a consistent profile for both on-road gasoline and diesel vehicles, respectively. Based on on-road fuel usage, diesel trucks dominate the IVOC emissions from on-road vehicles. These laboratory measurements are also compared with the measurements made in a traffic tunnel, and strong consistency is found between them.