Laboratory studies of the homogeneous nucleation of iodine oxides J. B. Burkholder1, J. Curtius1,*, A. R. Ravishankara1,**, and E. R. Lovejoy1 1Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305-3328, USA *now at: Institute for Atmospheric Physics, Mainz University, Mainz, Germany **also associated with the Dept. of Chemistry and Biochemistry, Uuniversity of Colorado, Boulder, CO 80309, USA
Abstract. Laboratory experimental results of iodine oxide nucleation are presented.
Nucleation was induced following UV photolysis of CF3I or CH2I2 in
the presence of excess ozone. Measurements were performed in a 70 L Teflon
reactor with new particles detected using an Ultrafine Condensation Particle
Counter, UCPC. The experimental results are interpreted using a coupled chemical
- aerosol model to derive model parameters assuming single component homogeneous nucleation of OIO. The aerosol model results have been
applied in an atmospheric box-model to interpret the possible implications of
iodine oxide nucleation in the marine boundary layer. The model calculations
demonstrate that IO and OIO concentrations reported in recent field measurements using long path absorption (Allan et al., 2000, 2001) are not
sufficient to account for significant aerosol production either in the coastal or open ocean marine boundary layer using the mechanism presented. We
demonstrate that inhomogeneous sources of iodine oxides, i.e.
"hot" spots with elevated iodine species emissions, could account for the aerosol
production bursts observed in the coastal region near Mace Head, Ireland.
Citation: Burkholder, J. B., Curtius, J., Ravishankara, A. R., and Lovejoy, E. R.: Laboratory studies of the homogeneous nucleation of iodine oxides, Atmos. Chem. Phys., 4, 19-34, doi:10.5194/acp-4-19-2004, 2004.