Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 9 6 2009 10.5194/acpd-9-27745-2009 http://www.atmos-chem-phys-discuss.net/9/27745/2009/ http://www.atmos-chem-phys-discuss.net/9/27745/2009/acpd-9-27745-2009.html http://www.atmos-chem-phys-discuss.net/9/27745/2009/acpd-9-27745-2009.pdf 27745 27789 2009-12-23 Organic aerosol components observed in worldwide datasets from aerosol mass spectrometry N. L. Ng M. R. Canagaratna mrcana@aerodyne.com Q. Zhang J. L. Jimenez J. Tian I. M. Ulbrich J. H. Kroll K. S. Docherty P. S. Chhabra R. Bahreini S. M. Murphy J. H. Seinfeld L. Hildebrandt P. F. DeCarlo V. A. Lanz A. S. H. Prevot E. Dinar Y. Rudich D. R. Worsnop Aerodyne Research, Inc. Billerica, MA, USA Atmospheric Sciences Research Center, State University of New York, Albany, NY, USA CIRES, University of Colorado, Boulder, CO, USA Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA Department of Chemical Engineering, California Institute of Technology, Pasadena, CA, USA NOAA, Earth System Research Laboratory, Boulder, CO, USA Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, USA Department of Atmospheric and Oceanic Science, University of Colorado, Boulder, CO, USA Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland Department of Environmental Sciences, Weizmann Institute of Science, Rehovot 76100, Israel now at: Department of Environmental Toxicology, University of California, Davis, CA, USA In this study we present results from the factor analysis of 43 aerosol mass spectrometer (AMS) datasets and provide an overview of worldwide organic aerosol (OA) components and their evolution in the atmosphere. At most sites, the OA can be separated into oxygenated OA (OOA), hydrocarbon-like OA (HOA), and sometimes other components such as biomass burning OA (BBOA). In many analyses, the OOA can be further deconvolved into low-volatility OOA (LV-OOA) and semi-volatile OOA (SV-OOA). A wide range of <i>f</i>₄₄ (ratio of <i>m/z</i> 44 to total signal in the component mass spectrum) and O:C ratios are observed for both LV-OOA (0.17&plusmn;0.04, 0.73&plusmn;0.14) and SV-OOA (0.07&plusmn;0.04, 0.35&plusmn;0.14) components, reflecting the fact that there is a continuum of OOA properties in ambient aerosol. Differences in the mass spectra of these components are characterized in terms of the two main ions <i>m/z</i> 44 (CO₂⁺) and <i>m/z</i> 43 (mostly C₂H₃O⁺). The LV-OOA component spectra have higher <i>f</i>₄₄ and lower <i>f</i>₄₃ than SV-OOA. The OOA components (OOA, LV-OOA, and SV-OOA) from all sites cluster within a well defined triangular region in the <i>f</i>₄₄ vs. <i>f</i>₄₃ space, which can be used as a standardized means of comparing and characterizing any OOA components (laboratory or ambient) observed with the AMS. Examination of the OOA components in this triangular space indicates that OOA component spectra become increasingly similar to each other and to fulvic acid and HULIS sample spectra as <i>f</i>₄₄ (a surrogate for O:C and an indicator of photochemical aging) increases. This indicates that ambient OA converges towards highly aged LV-OOA with atmospheric oxidation. The common features of the transformation between SV-OOA and LV-OOA at multiple sites potentially enables a simplified description of the oxidation of OA in the atmosphere. 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