A functional group oxidation model (FGOM) for SOA formation and aging 1Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
18 Jun 2013
2Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
Received: 28 November 2012 – Published in Atmos. Chem. Phys. Discuss.: 18 December 2012 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. (2013) is discussed.
Revised: 30 April 2013 – Accepted: 20 May 2013 – Published: 18 June 2013
Citation: Zhang, X. and Seinfeld, J. H.: A functional group oxidation model (FGOM) for SOA formation and aging, Atmos. Chem. Phys., 13, 5907-5926, doi:10.5194/acp-13-5907-2013, 2013.