A Modeling Study of Impacts of Dust Surface Heterogeneous Chemistry on Atmospheric Pollutants Concentrations in China during a Dust Storm Event

In this study, the impact of dust surface heterogeneous chemistry on the pollutants over China during 22-29 April 2009 is investigated by using GEOS-Chem model driven by GEOS-5 assimilated meteorological field from the Goddard Earth Observing System (GEOS). During the dust storm period, the simulated concentrations of dust nitrate and dust sulfate averaged over China are about 0.2 μg m^-3 and 0.4 μg m^-3, respectively, which account for 24% of the total nitrate (sum of non-dust and dust nitrate) and 10% of the total sulfate (sum of non-dust and dust sulfate), respectively. The percentage of total nitrate accounted for by dust nitrate in western China is higher than those in other regions by more than 80%, while the percentage of the total sulfate accounted for by dust sulfate is lower than those in the down-wind areas. After considering the dust surface heterogeneous chemistry, the simulated changes in concentrations of sulfur dioxide (SO₂), nitric acid (HNO₃), ozone (O₃), non-dust sulfate, total sulfate, non-dust nitrate, total nitrate, NH₃, and ammonium averaged over China during the dust storm event are about -7%, -15%, -2%, -8%, 3%, -2%, 14%, 21%, and -5% by percentage, respectively.