AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Explicit Modeling of Multi-generational Aging of Organic Aerosol in an Air Quality Model
SHANTANU JATHAR, Anthony Wexler, Christopher Cappa, Michael Kleeman, University of California, Davis
Abstract Number: 197 Working Group: Aerosol Chemistry
Abstract Climate and air quality models lack or incorporate a simple and unconstrained treatment of the multi-generational aging of organic gases, a pathway that could improve organic aerosol (OA) model performance and bears heavily on OA’s climate- and health-relevant properties. Here we implement an explicit oxidation scheme (Cappa and Wilson, ACP, 2012) parameterized using recent experimental data in a regional air quality model to simulate the influence of multi-generational aging of OA. The scheme includes a resolved treatment of carbon size and molecular structure (linear, branched, cyclic) for alkanes and a lumped treatment for aromatics and biogenics. We use the air quality model to simulate two summertime episodes over Southern California for which comprehensive air quality measurements are available: July-August 2005 (SOAR) and May-June 2010 (CalNex). Results will be compared to measurements to determine if multi-generational aging substantially enhances region-wide daily-averaged OA concentrations. Evaluations at Riverside, CA and Pasadena, CA based on measurements will be used to determine if the model improves predictions of OA’s diurnal profile, degree-of-oxygenation and fossil-versus-modern fraction.