AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Secondary Organic Aerosol (SOA) and Ozone Formation from Photo-Oxidation of Unburned Whole Gasoline and Diesel
WEIHUA LI, Chia-Li Chen, Lijie Li, Mary Kacarab, David R. Cocker III, University of California, Riverside
Abstract Number: 570 Working Group: Aerosol Chemistry
Abstract Direct evaporation from unburnt gasoline and diesel fuels is an established source of ozone and SOA forming hydrocarbon precursors. As new control technologies continue to decrease primary OA and gas-phase vehicle emissions, whole fuel evaporation becomes a more significant source of ambient aerosol formation. Therefore, determining the SOA forming potential of whole gasoline and diesel vapor is of significant interest. While SOA formation from some gasoline components such as aromatics have been individually studied under controlled conditions, there are only a few studies on how these complex mixtures behave in the atmosphere.
Given changes in fuel formulations over time, it is important to revisit whole gasoline as an important SOA precursor, especially in light of increased knowledge on the impact of reactivity on aerosol formation and improved atmospheric chambers and instrumentation. Multiple photo-oxidation experiments with the presence of NOx were conducted in the UCR CE-CERT dual 90m3 smog chambers to investigate SOA and ozone formation from three different types of unburned fuels: commercial gasoline, commercial diesel, and reference fuels. Additionally, the fuels were also added to a surrogate mixture to best mimic the reactivity of an urban atmosphere. Liquid gasoline and diesel samples were collected at service stations during winter 2016 in Riverside, California and characterized by using gas-chromatography methods. Data will be presented comparing the aerosol formation from the different whole fuels in the presence of NOX and also in the controlled reactivity system. SOA bulk chemical composition characteristics in the different systems were identified by the HR-ToF-AMS. Physical properties of the resulting aerosol, such as density and volatility will also be presented. The goal of this work was to investigate the influence of fuel composition on SOA formation and properties and ozone formation.