Laboratory studies of the homogeneous nucleation of iodine oxides

[摘要] Laboratory experimental results of iodine oxide nucleation are presented.Nucleation was induced following UV photolysis of CF₃I or CH₂I₂ inthe presence of excess ozone. Measurements were performed in a 70 L Teflonreactor with new particles detected using an Ultrafine Condensation ParticleCounter, 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 beenapplied in an atmospheric box-model to interpret the possible implications ofiodine oxide nucleation in the marine boundary layer. The model calculationsdemonstrate that IO and OIO concentrations reported in recent field measurements using long path absorption (Allan et al., 2000, 2001) are notsufficient to account for significant aerosol production either in the coastal or open ocean marine boundary layer using the mechanism presented. Wedemonstrate that inhomogeneous sources of iodine oxides, i.e."hot" spots with elevated iodine species emissions, could account for the aerosolproduction bursts observed in the coastal region near Mace Head, Ireland.

[学科分类] 大气科学