Toward a general parameterization of N2O5 reactivity on aqueous particles: the competing effects of particle liquid water, nitrate and chloride T. H. Bertram1,* and J. A. Thornton1 1Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA *now at: Department of Chemistry, University of California San Diego, La Jolla, CA
Abstract. The heterogeneous reaction of N2O5 on mixed organic-inorganic
aerosol particles was investigated using an entrained aerosol flow tube
coupled to a custom-built chemical ionization mass spectrometer. Laboratory
results on aqueous particles confirm a strong dependence of the reactive
uptake coefficient (γ) on particle liquid water, for particle water
concentrations below 15 M, and the molar ratio of particle water to nitrate.
Measurements of γ (N2O5) on mixed chloride-nitrate
particles indicate that the presence of trace chloride can negate the
suppression of γ(N2O5) at high nitrate loadings with
implications for polluted coastal regions. These results are used to
construct a new parameterization for γ (N2O5), that when
coupled to an aerosol thermodynamics model, can be used within regional
and/or global chemical transport models.
Citation: Bertram, T. H. and Thornton, J. A.: Toward a general parameterization of N2O5 reactivity on aqueous particles: the competing effects of particle liquid water, nitrate and chloride, Atmos. Chem. Phys., 9, 8351-8363, doi:10.5194/acp-9-8351-2009, 2009.