Atmos. Chem. Phys. Discuss., 11, 2025-2055, 2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Secondary Organic Aerosol formation from phenolic compounds in the absence of NOx
S. Nakao1,2, C. Clark1,2, P. Tang1,2, K. Sato2,*, and D. Cocker III1,2
1University of California, Riverside, Department of Chemical and Environmental Engineering, Riverside, California, USA
2College of Engineering – Center for Environmental Research and Technology (CE-CERT), Riverside, California, USA
*currently at: National Institute for Environmental Studies, Japan

Abstract. SOA formation from benzene, toluene, m-xylene, and their corresponding phenolic compounds were investigated using the UCR/CE-CERT Environmental Chamber to evaluate the importance of phenolic compounds as intermediate species in aromatic SOA formation. SOA formation yield measurements coupled to gas-phase yield measurements indicate that approximately 20% of the SOA of benzene, toluene, and m-xylene could be ascribed to the phenolic route. The SOA densities tend to be initially as high as approximately 1.8 g/cm3 and eventually reach the range of 1.3–1.4 g/cm3. The final SOA density was found to be independent of elemental ratio (O/C) indicating that applying constant density (e.g., 1.4 g/cm3) to SOA formed from different aromatic compounds is a reasonable approximation. Results from a novel on-line PILS-ToF (Particle-into-Liquid Sampler coupled with Agilent Time-of-Flight) are reported. Major signals observed by the on-line/off-line ToF include species consistent with bicyclic hydroperoxides. To the authors' best knowledge, this is the first possible detection of bicyclic hydroperoxides in aromatic SOA.

Citation: Nakao, S., Clark, C., Tang, P., Sato, K., and Cocker III, D.: Secondary Organic Aerosol formation from phenolic compounds in the absence of NOx, Atmos. Chem. Phys. Discuss., 11, 2025-2055, doi:10.5194/acpd-11-2025-2011, 2011.
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