Heterogeneous nucleation of ice catalyzed by high molecular weight organic compounds, before and after ozonolysis, using octadecene as a model

High altitude clouds may be affected by the products of biomass burning, which can be lofted into the upper troposphere through deep convection. To further complicate the picture, once in the atmosphere, organic compounds may be transformed through oxidation, possibly changing their characteristics as freezing catalysts. Using 1- and 9-octadecene as a model for unsaturated, non-polar high molecular weight organic compounds, we will show that exposure to ozone does not change the characteristic temperature at which a coating of octadecene catalyzes heterogeneous ice nucleation. In addition, the phase of the octadecene (liquid or crystalline) when ozonolysis takes place does not affect the characteristic freezing temperature. Results from studies of the same system using infrared spectroscopy will also be presented.