. Time evolution of laboratory biomass burning aerosols. Relations between aerosol chemical composition, volatility and optical properties.

Abstract
Aerosols emitted from wildfires impact human health and the Earth's climate. Wildfire emissions are challenging to understand because of their complexity and variability for different phases of the fire and for different wood types. To address this we present the results of an extensive set of laboratory burns during the NOAA 2016 FIREX measurement campaign at the Missoula Fire Science Laboratory. The goal of the campaign was to understand emissions of wood burning in a simplified and controlled environment. We sampled emissions from more than 35 different fuels relevant for the Western United States using an Aerosol Mass Spectrometer at high time resolution (<1 s). We show how the results of our extensive analysis elucidating how the chemical composition of the biomass-burning aerosols changes for different phases of the fire and for different wood types. We also relate these changes to the co-emitted gas phase volatile organic compounds (VOC), with aerosol volatility, and aerosol optical properties.