AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Secondary Organic Aerosol (SOA) Formation from a Light-Duty Gasoline Direct Injection (GDI) Vehicle at Different Drive Conditions
WEIHAN PENG, Niina Kuittinen, Cavan McCaffery, Stephen Zimmerman, Patrick Roth, Roya Bahreini, David R. Cocker III, Georgios Karavalakis, University of California, Riverside
Abstract Number: 786 Working Group: Combustion
Abstract Aerosol particle emissions from vehicular-related activities is important to particulate matter emission budget in urban areas. As emission control technologies for primary aerosols (PA) advance, secondary organic aerosol (SOA) becomes increasingly important. Unlike primary aerosol directly emitted to atmosphere, SOA forms from gas-particle partitioning of reactions products from VOCs, NOx, and other species in atmosphere. Studies have shown SOA formation potential from GDI vehicles for select drive cycles (e.g. LA92, FTP). However, no comprehensive studies have characterized SOA formation at different drive conditions: aggressive and mild, hot- and cold- start. This work investigates the primary and secondary aerosol composition from a GDI vehicle when operated over 7 different drive cycles, including FTP, NEDC, LA92, US06, HWFET and two high-speed drive cycles developed by California Department of Transportation (Caltrans).
Emission samples were collected from a GDI light-duty vehicle operating California E10 fuel and atmosphere aging products were studied at the Mobile Atmospheric Chamber (MACh) at UC, Riverside/CECERT. The particle size distribution, density, volatility and aerosol bulk chemical composition were analyzed. Both primary and secondary pollutants from this vehicle were compared between more and less aggressive cycles, hot- and cold- start cycles, to investigate the effects from cycle starting conditions and speed on SOA formation. Black carbon and ammonium nitrate account for the major fraction of tailpipe emission and chamber aging aerosol products respectively, when operated over all drive cycles in this study.