Monday, September 22, 2008

Collaborative work in the Finlayson-Pitts and Tobias groups reveals a surface enhancement in the photochemistry of sodium chloride-sodium nitrate aerosol mixtures. In a recent hot article in PCCP, their research showed that UV photolysis of aerosols containing both nitrate and chloride ions yields significantly more NO2 than irradiation of pure sodium nitrate aerosols. Molecular dynamics simulations shed light on the experiments showing that the interfacial chloride ions form a double layer with sodium ions, which then attract nitrate ions to the surface. The reduced solvent cage of the near-surface nitrate ions allows for easier escape of photoproducts. The results have implications in coastal urban areas and in the polar regions where sea salt influences the composition of aerosols.

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