Biofuel-Specific Molecular Composition of Organic Aerosol in Biomass Burning Smoke

KYLA SIEMENS, Theo Paik, August Li, Felipe Rivera-Adorno, Jay Tomlin, Rajan K. Chakrabarty, Alexander Laskin, Purdue University

     Abstract Number: 522
     Working Group: Aerosol Chemistry

Abstract
Organic aerosol (OA) emitted from wildfires and prescribed forest and agricultural burning have diverse composition that undergo complex reactions and transformations in the atmosphere, leading to profound impacts on air quality, climate, and atmospheric chemistry. Emission characteristics are strongly dependent on regional vegetation, with different fuels resulting in substantially different OA component profiles. Understanding the emission profiles of these biomass fuels is fundamental in predicting their impact on atmospheric consequences of wild and prescribed fires. In this work, we characterize OA emissions of peat, sage grass, grass, and ponderosa pine burned in controlled laboratory environments. We utilize ultra-high-performance liquid chromatography coupled to a photodiode array detector and electrospray ionization high-resolution mass spectrometer (UPLC-PDA-ESI-HRMS) to investigate molecular characteristics of smoldering-phase emissions to model the contributions of these fuels in real-world burns. We showcase a method to determine the volatility profiles of the OA samples representative of studied fuel-types and their relationship to the light-absorbing properties of brown carbon (BrC) with respect to four optically based BrC classes (very weak, weak, moderate and strongly absorbing). This method of classification is practical for analyzing and comparing light absorbing OA samples and is applicable for both laboratory-based and real-world studies.