AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Effect of Criegee Biradical Reactions on Regional Secondary Inorganic and Organic Aerosol
JINGYI LI, Qi Ying, Texas A&M University
Abstract Number: 460 Working Group: Aerosol Chemistry
Abstract Recent studies show that reactions rates of criegee biradicals, generated from ozonolysis of alkenes, with SO2 and NO2 are much faster than previously estimated. This leads to speculations that the criegee radicals may play a more significant role in regional and global budgets of sulfate and potentially indirectly affect other secondary pollutants such as secondary organic aerosol (SOA). In this study, the Community Multiscale Air Quality (CMAQ) model with Master Chemical Mechanism version 3.2 (MCM v3.2) is applied to evaluate the effect of faster criegee biradical reaction rates with SO2 and NO2 on regional concentrations of sulfate and SOA. The secondary organic aerosol concentrations are predicted by directly partitioning thousands of semivolatile volatile organic compounds predicted by the gas phase MCM mechanism into the organic phase of the aerosols. The CMAQ-MCM-SOA model will be applied to study regional sulfate and SOA in southeast US and in the Mexico City. While southeast US represents an area with significant biogenic emissions with influence from anthropogenic emissions, Mexico City represents an area with significant anthropogenic alkene emissions and high SO2 concentrations from fossil fuel combustion and natural sources. Difference between the base case simulation with original criegee radical reaction rate coefficients and the sensitivity case with recent estimated faster reaction rate coefficients will be used to quantify the impact of the proposed new reaction kinetics data on regional secondary aerosol concentrations. Effect of these changes on direct radiative forcing will be estimated.