AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
OH-initiated Aging of Biomass Burning Aerosol during FIREX
CHRISTOPHER LIM, David Hagan, Christopher Cappa, Jesse Kroll, Matthew Coggon, Abigail Koss, Kanako Sekimoto, Carsten Warneke, MIT
Abstract Number: 283 Working Group: Aerosol Chemistry
Abstract Biomass burning emissions represent a major source of fine particulate matter to the atmosphere, and this source will likely become increasingly important due to changes in the Earth’s climate. Understanding the effects that increased fire emissions have on both air quality and climate require understanding the composition of the the particles emitted, as chemical and physical composition directly impact important particle properties such as absorptivity, toxicity, and cloud condensation nuclei activity. However, the composition of biomass burning particles in the atmosphere is dynamic, as the particles are subject to the condensation of low-volatility vapors and reaction with oxidants such as the hydroxyl radical (OH) during transport. Here we present a series of laboratory chamber experiments on the OH-initiated aging of biomass burning aerosol performed at the Fire Sciences Laboratory in Missoula, MT as part of the Fire Influences on Regional and Global Environments Experiment (FIREX) campaign. We describe the evolution of biomass burning aerosol produced from a variety of fuels operating the chamber in both particle-only and gas + particle mode, focusing on the organic composition. In particle-only mode, gas-phase biomass burning emissions are removed before oxidation to focus on heterogeneous oxidation, while gas + particle mode includes both heterogeneous oxidation and condensation of oxidized volatile organic compounds onto the particles. Variability in fuels and burning conditions lead to differences in aerosol loading and secondary aerosol production. Despite this variability, aging of all burns showed significant increases in average carbon oxidation state with OH exposure.