Seminar

Abstract

Atmospheric aerosols pose serious health risks and have a substantial influence on Earth's climate. Biomass burning emissions are a major source of atmospheric aerosols on the global scale. Field studies reveal that atmospheric processing can substantially alter these emissions downwind of fires; these transformations must be understood to quantify the effects of biomass burning on global climate.

In the fall of 2009 we conducted a series of smog chamber experiments to investigate the atmospheric evolution of organic aerosol emissions from simulated wildfires at the Fire Science Laboratory in Missoula, MT. In this talk, I will present some of the preliminary results from these experiments including thermodenuder measurements of fresh and aged aerosol volatility, the effects of aging on organic aerosol mass and composition, and new particle formation. In many experiments, there was substantial production of new organic aerosol mass, greatly in excess of that predicted by a state of the art atmospheric chemistry model. However, in some experiments, photo-oxidation caused a loss of organic aerosol mass. Aerosol mass spectrometer data and filter measurements reveal significant chemical processing of the organic aerosol emissions, including substantial decay of levoglucosan, a major product of cellulose combustion that is commonly used as a tracer for biomass burning aerosols.