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.