AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Secondary Organic Aerosol Production from Intermediate Volatility Organic Compound Emissions from On-road Vehicles
YUNLIANG ZHAO, Ngoc Nguyen, Albert A. Presto, Christopher Hennigan, Andrew May, Allen Robinson, Carnegie Mellon University
Abstract Number: 218 Working Group: Combustion
Abstract Results from smog chamber experiments with dilute exhaust from on-road vehicles, both gasoline and diesel vehicles, have shown that the amount of secondary organic aerosol (SOA) produced during experiments can not be explained by traditional SOA precursors such as single-ring aromatic compounds. Intermediate-volatility organic compounds (IVOCs) have been proposed as the major cause for the discrepancies between measured SOA in chamber experiments and estimated SOA from single-ring aromatic compounds. To examine the importance of IVOCs in SOA production, IVOC emissions were directly measured from gasoline and diesel on-road vehicles during chassis dynamometer testing. The mass of IVOCs is dominated by an unresolved complex mixture (UCM). The UCM is quantified into 22 lumped groups based on molecular structure and volatility. SOA production from IVOCs, both speciated IVOCs and the UCM, are estimated and compared to SOA production measured in the smog chamber experiments with dilute exhaust. Our results show that SOA production from IVOCs is the dominant contributor to SOA produced from diesel exhaust, and a major contributor to SOA produced from gasoline exhaust. Finally we use the new data to re-examine the contribution of gasoline and diesel on-road vehicles to atmospheric SOA