AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Source-resolved Simulation of Fresh and Chemically-aged Biomass Burning Emissions
LAURA POSNER, Georgia Theodoritsi, Ksakousti Skyllakou, Bonyoung Koo, Matthew Mavko, Spyros Pandis, Allen Robinson, Carnegie Mellon University, University of Patras
Abstract Number: 340 Working Group: Source Apportionment
Abstract Biomass burning can be a significant source of organic aerosol, both locally and far downwind. Most previous modeling work assumes that biomass burning primary organic aerosol (POA) is non-volatile, but as the emissions travel and dilute, the oxidation of evaporated semi-volatile POA forms secondary organic aerosol (SOA). In this study, the 3D chemical transport model PMCAMx was used to simulate the emission and evolution of biomass burning organic aerosol (bbOA) to determine its predicted contribution to total organic aerosol (OA) concentrations in the continental U.S. PMCAMx simulates the evolution of semi-volatile POA and the formation of SOA using the volatility basis set framework. A source-resolved emission inventory for the continental U.S. was used as input for PMCAMx to simulate three representative months with significant biomass burning for the modeling year 2008. Corresponding zero-out simulations were then performed to determine the predicted contribution of bbOA to total OA concentrations. The zero-out results were compared to the results of PSAT, a source-tracking module within PMCAMx.
A source-resolved version of PMCAMx (PMCAMx-SR) was then used to simulate the same representative months to investigate the importance of the volatility representation of bbOA. PMCAMx-SR allows bbOA emissions and their oxidation products to be represented and tracked separately from other OA sources and to have their own volatility distribution and chemical aging scheme. The sensitivity of the predicted contribution of biomass burning OA to assumptions about the emissions of unknown VOCs, IVOCs, and the assumed volatility distribution of bbOA emissions was investigated. These results were used to estimate the importance of biomass burning as an OA source in the U.S.