AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Estimating the Contribution of Significant Volatile Organic Compounds to Secondary Organic Aerosol from Biomass Cookstove Emissions
ADITYA SINHA, Ingrid George, Michael Hays, Andrew Grieshop, North Carolina State University
Abstract Number: 715 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract Almost 3 billion people use biomass cookstoves with emissions resulting in adverse impacts on both health and climate. Emissions from these cookstoves include volatile organic compounds (VOCs), which include hazardous pollutants and various precursors to secondary organic aerosol (SOA). However, the identity and extent to which individual VOCs from biomass stove emissions contribute to SOA production is poorly understood. To better constrain VOC identity and quantity for a range of stoves and fuels, we analyzed whole air samples (WAS) of fresh and photochemically-aged emissions using EPA method (TO-15). Using literature yields, we estimate their contribution to SOA observed in an oxidation flow reactor and quantify mass closure in SOA. Preliminary results indicate that Benzene, Naphthalene and Toluene, were capable of explaining up to ∼65% of the SOA observed in tests of the most efficient stove, but in other cases only ∼10% of SOA formed were explained by these VOCs. On an emission factor basis, the lower combustion efficiency stoves resulted in higher VOCs. SOA contributions from benzene and naphthalene were similar and higher than those from toluene across all conditions. Current work will identify compounds not targeted by the TO-15 protocol, like phenol and derivatives identified as significant SOA precursors, using deconvolution algorithms (‘unknowns’ analysis) on existing sample analyses. We hypothesize that with the incorporation of VOCs from both targeted and semi-quantitatively estimated non-targeted compounds, we can bridge the gap in unaccounted observed SOA mass. We also explore an alternative approach to explaining the SOA by projecting the VOC measurements from canister sampling, and separate measurements of semi- and intermediate-volatility organic compounds (S/IVOCs) from thermal desorption analysis of collected filters in a volatility basis set (VBS) framework. We will investigate how SOA formation from detailed VOC speciation data compares to estimates applying this VBS framework in explaining observed SOA from cookstove emissions.