Atmos. Chem. Phys. Discuss., 12, 32565-32611, 2012
www.atmos-chem-phys-discuss.net/12/32565/2012/
doi:10.5194/acpd-12-32565-2012
© Author(s) 2012. 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.
A Functional Group Oxidation Model (FGOM) for SOA formation and aging
X. Zhang1 and J. H. Seinfeld1,2
1Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
2Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA

Abstract. Secondary organic aerosol (SOA) formation from a volatile organic compound (VOC) involves multiple generations of oxidation that include functionalization and fragmentation of the parent carbon backbone and, likely, particle-phase oxidation and/or accretion reactions. Despite the typical complexity of the detailed molecular mechanism of SOA formation and aging, a relatively small number of functional groups characterize the oxidized molecules that constitute SOA. Given the carbon number and set of functional groups, the volatility of the molecule can be estimated. We present here a Functional Group Oxidation Model (FGOM) that represents the process of SOA formation and aging. The FGOM contains a set of parameters that are to be determined by fitting of the model to laboratory chamber data: total organic aerosol concentration, and O:C and H:C atomic ratios. The sensitivity of the model prediction to variation of the adjustable parameters allows one to assess the relative importance of various pathways involved in SOA formation. An analysis of SOA formation from the high- and low-NOx photooxidation of four C12 alkanes (n-dodecane, 2-methylundecane, hexylcyclohexane, and cyclododecane) using the FGOM is presented, and comparison with the Statistical Oxidation Model (SOM) of Cappa et al. (2012) is discussed.

Citation: Zhang, X. and Seinfeld, J. H.: A Functional Group Oxidation Model (FGOM) for SOA formation and aging, Atmos. Chem. Phys. Discuss., 12, 32565-32611, doi:10.5194/acpd-12-32565-2012, 2012.
 
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