Articles | Volume 12, issue 24
Atmos. Chem. Phys., 12, 11795–11817, 2012
Atmos. Chem. Phys., 12, 11795–11817, 2012

Research article 17 Dec 2012

Research article | 17 Dec 2012

Analysis of secondary organic aerosol formation and aging using positive matrix factorization of high-resolution aerosol mass spectra: application to the dodecane low-NOx system

J. S. Craven1, L. D. Yee2, N. L. Ng6, M. R. Canagaratna3, C. L. Loza1, K. A. Schilling1, R. L. N. Yatavelli4,*, J. A. Thornton4, P. J. Ziemann5, R. C. Flagan1,2, and J. H. Seinfeld1,2 J. S. Craven et al.
  • 1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
  • 2Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California, USA
  • 3Aerodyne Research, Inc., Billerica, Massachusetts, USA
  • 4Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA
  • 5Air Pollution Research Center, Department of Environmental Sciences, and Environmental Toxicology Graduate Program, University of California, Riverside, California, USA
  • 6School of Chemical and Biomolecular Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
  • *current address: Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado, USA

Abstract. Positive matrix factorization (PMF) of high-resolution laboratory chamber aerosol mass spectra is applied for the first time, the results of which are consistent with molecular level MOVI-HRToF-CIMS aerosol-phase and CIMS gas-phase measurements. Secondary organic aerosol was generated by photooxidation of dodecane under low-NOx conditions in the Caltech environmental chamber. The PMF results exhibit three factors representing a combination of gas-particle partitioning, chemical conversion in the aerosol, and wall deposition. The slope of the measured high-resolution aerosol mass spectrometer (HR-ToF-AMS) composition data on a Van Krevelen diagram is consistent with that of other low-NOx alkane systems in the same O : C range. Elemental analysis of the PMF factor mass spectral profiles elucidates the combinations of functionality that contribute to the slope on the Van Krevelen diagram.

Final-revised paper