Heterogeneous ozonation kinetics of phenanthrene at the air?ice interface
Phenanthrene ozonation kinetics were measured on ice at ?30 and ?10??C, and on a water surface at 22??C using glancing angle laser-induced fluorescence. A Langmuir?Hinshelwood type kinetic mechanism was observed on ice. The maximum ozonation rates were a factor of ten higher on ice than on water. No temperature dependence to the kinetics was observed between ?30 and ?10??C, suggesting that the differences in the rates on ice and water are due to different physical properties at the two surfaces. Fluorescence spectra of phenanthrene show significant self-association on ice that is not observed on water, adding further evidence for the hypothesis that the quasi-liquid layer at the air?ice interface presents a very different environment to liquid water.