Chemical Composition and Photolytic Aging of Urban Material Burning Smoke

SERGEY NIZKORODOV, Matt Zaragoza, Luis Ruiz Armenta, Noam Levi, Katherine Hopstock, Manabu Shiraiwa, Abigail Smith, Qiaorong Xie, Alexander Laskin, Gregory W. Vandergrift, Swarup China, Zezhen Cheng, Shantanu Jathar, Zoë Golay, Evan Chartrand, Allan K. Bertram, University of California, Irvine

     Abstract Number: 168
     Working Group: Burning Questions of Aerosol Emissions, Chemistry, and Impacts from Wildland-Urban Interface (WUI) Fires

Abstract
Wildfire events increasingly occur at the wildland-urban interface, burning not only biomass but also a wide range of urban materials. This presentation will focus on the chemical composition and important physical properties of particulate matter from pyrolysis and smoldering of common urban materials. Specifically, we measure mass absorption coefficients by spectrophotometry, perform untargeted analysis of samples by ultrahigh resolution mass spectrometry, measure particle viscosity by poke-flow and fluorescence recovery after photobleaching methods, measure distribution of effective saturation vapor pressures by thermal desorption mass spectrometry methods, and study the effect of UV-aging on all of these properties. We observe that exposure of OA to solar radiation tends to increase particle viscosity, change solubility and reduce the volatilities of particulate compounds. At the same time, the absorption coefficient can either be reduced (photobleaching) or increased (photoenhancement), reflecting complex aging mechanisms driven by condensed phase photochemical reactions in OA.