AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Laboratory Measurements of Organic Aerosol Chemical Composition: Primary Emissions and Secondary Formation from Biomass Combustion
BRENT WILLIAMS, Raul Martinez, Peter Mellott, Dhruv Mitroo, Yaping Zhang, Pratim Biswas, Andrew Lambe, Kenneth Christian, William Brune, Thorsten Hohaus, Manjula Canagaratna, John Jayne, Douglas Worsnop, Washington University in St. Louis
Abstract Number: 507 Working Group: Aerosol Chemistry
Abstract Biomass combustion contributes substantially to the atmospheric loading of organic trace gases and particles. Organic gases undergo atmospheric photooxidation to produce secondary organic aerosol. Atmospheric primary and secondary organic aerosol causes source-specific impacts on climate and is detrimental to human health. Of the major contributing sources to atmospheric fine particle mass, the direct emissions and secondary aerosol formation potential of biomass burning remains one of the least understood. This is largely due to the complexity in combustion conditions and the wide variety of biomass fuel types.
We have begun an investigation, utilizing fully automated high time resolution instrumentation and novel laboratory methods, to characterize the chemistry and particulate burden of biomass burning emissions under variable combustion and photooxidation conditions and for various biomass fuel types. Instrumentation includes the thermal desorption aerosol gas chromatograph (TAG) for individual organic compound analysis combined with a high resolution time-of-flight aerosol mass spectrometer (AMS) for total organic, sulfate, nitrate, ammonium, and chloride mass concentrations as well as elemental ratios of O:C, H:C, N:C to determine oxidation state and nitrogen content. Laboratory setup includes both an emissions/combustion chamber and a drop tube furnace coupled to a potential aerosol mass (PAM) flow tube reactor to mimic atmospheric photochemical processing of gas-phase emissions and heterogeneous reactions on primary aerosol. Results from combustion of several plant species and plant fractions will be presented.