American Association for Aerosol Research - Abstract Submission

AAAR 36th Annual Conference
October 16 - October 20, 2017
Raleigh Convention Center
Raleigh, North Carolina, USA

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Aerosol Sulfate Production in Extreme Air Quality Episodes

V. FAYE MCNEILL, Kelsey Reed, Athanasios Nenes, Columbia University

     Abstract Number: 136
     Working Group: There Must be Something in the Water: Cloud, Fog and Aerosol Aqueous Chemistry for Aerosol Production

Extreme air quality episodes are becoming increasingly frequent in megacities around the world. Accurate understanding and modeling of the atmospheric chemistry that leads to these episodes is necessary for the development of effective and economical policies for their prevention, and the protection of public health.

We discuss detailed modeling of sulfate production under the conditions representative of extreme pollution events in Beijing using both an equilibrium model and a kinetic approach using GAMMA 4.0, the McNeill Group model of multiphase atmospheric chemistry. We analyze the contribution of several sulfate formation pathways. In-particle sulfate formation chemistry is exquisitely sensitive to aerosol acidity, as determined by both thermodynamics and the kinetics of reactions which generate or consume H3O+. We find that detailed kinetic accounting of H3O+reveals possible limits on the SO2+NO2 pathway which has been proposed by other investigators.