Exploring the Phase Behavior of Biomass Burning Aerosols

NEALAN GERREBOS, F.K.A. Gregson, Julia Zaks, Allan K. Bertram, University of British Columbia

     Abstract Number: 215
     Working Group: Aerosol Chemistry

Abstract
Liquid-liquid phase separation (LLPS) in atmospheric organic aerosols has wide ranging impacts, from affecting the lifetimes of pollutants to impacting cloud formation. It has previously been shown that coexistence of two or three liquid phases can occur in particles consisting of secondary and primary organic aerosols and inorganic salts, and is dependent on the constituent species having a wide range of oxygen-to-carbon ratios. However, little work has been done to investigate the prevalence of LLPS in biomass burning aerosols (BBA), a major class of organic aerosol. The composition of BBA, and thus the presence of LLPS, depends on the burning temperature, the type of fuel that combusts, and the aging processes that the aerosols have been subject to. Relative humidity also plays a crucial role. We used a temperature-controlled flow tube furnace to generate BBA from different burning or smoldering temperatures, and collected aerosols by impaction on glass slides to observe LLPS with a variety of microscopy techniques. We then compare the lab-generated samples to extracts of BBA collected from wildfires in British Columbia to assess how well lab conditions can approximate those in the real world.