Reactive uptake coefficients for heterogeneous reaction of N2O5 with submicron aerosols of NaCl and natural sea salt D. J. Stewart, P. T. Griffiths, and R. A. Cox Centre for Atmospheric Science, Dept. of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
Abstract. The kinetics of uptake of gaseous N2O5 on submicron aerosols containing NaCl and natural sea
salt have been investigated in a flow reactor as a function of relative humidity (RH) in the range
30-80% at 295±2K and a total pressure of 1bar. The measured uptake coefficients, γ, were
larger on the aerosols containing sea salt compared to those of pure NaCl, and in both cases
increased with increasing RH. These observations are explained in terms of the variation in the
size of the salt droplets, which leads to a limitation in the uptake rate into small particles. After
correction for this effect the uptake coefficients are independent of relative humidity, and agree
with those measured previously on larger droplets. A value of γ=0.025 is recommended for the
reactive uptake coefficient for N2O5 on deliquesced sea salt droplets at 298K and RH>40%.
Citation: Stewart, D. J., Griffiths, P. T., and Cox, R. A.: Reactive uptake coefficients for heterogeneous reaction of N2O5 with submicron aerosols of NaCl and natural sea salt, Atmos. Chem. Phys., 4, 1381-1388, doi:10.5194/acp-4-1381-2004, 2004.