Projected climate change is strongly influenced by clouds. The oxidative processing of pollutants in clouds affects droplet size and reflectivity, important climatic effects. Clouds contain naturally occurring lipids forming films on the droplet and unusually involves aqueous nitrate radical chemistry. Oxidation and removal of this film can cause cloud evaporation or new cloud formation. We will study the kinetics of aqueous nitrate radicals with DSPC. Specifically, (a) demonstrate that a common aqueous cloud oxidant, nitrate radical, can penetrate into the organic film and remove the film, (b) calculate the effect of the reaction on the hygroscopic properties of a cloud droplet and demonstrate organic film removal may cause cloud to evaporation, (c) measure the kinetic rate constants for film oxidation and assess atmospheric relevance (d) Support a STFC/NERC CASE award PhD student.