Elemental Analysis and Oxidation of Chamber Organic Aerosol

Puneet Chhabra Aerodyne Research, Inc.
Nga Lee Ng Georgia Institute of Technology
Manjula Canagaratna Aerodyne Research, Inc.
Ashley Corrigan Scripps Institution of Oceanography
Lynn Russell Scripps Institution of Oceanography
Douglas Worsnop Aerodyne Research, Inc.
Richard Flagan California Institute of Technology
John Seinfeld California Institute of Technology

Category: Aerosol Properties

The principal means of assessing the rates of formation and composition of organic aerosol is laboratory chamber studies. Aerosol composition measurements with the Aerodyne Aerosol Mass Spectrometer (AMS) have demonstrated the wide range in the degree of oxygenation of ambient and chamber secondary organic aerosol (SOA). In this work, we investigate the elemental composition (C, H, O) and oxidation of chamber organic aerosol from a wide assortment of anthropogenic and biogenic precursors, including glyoxal, alpha-pinene, isoprene, aromatics, naphthalene, methoxyphenols, and unsaturated aldehydes. Using the “triangle plot” (Ng et al. 2010) and the Van Krevelen diagram (Heald et al. 2010), we compare SOA spectra from different precursors and discuss the similarities of elemental ratios derived from HR AMS spectra and offline speciation techniques. We find that elemental composition estimates from the AMS agree well with molecular speciation studies that have a substantial percentage of mass closure. We also find that LV-OOA O:C ratios can be achieved with oxygenated precursors in chamber experiments, and the “triangle region” can be outlined by chamber SOA spectra.

This poster will be displayed at ASR Science Team Meeting.