Quantifying amount, composition and fate of surface-active organic aerosols originating from cooking processes is a key atmospheric research activity. Our project aims to investigate the oxidation of organic-coated aerosols, particularly for the key night-time oxidant NO3. We carried out experiments on single components and recently moved to more realistic models for cooking aerosols, studying the binary mixtures of the three previously investigated surfactants. We will study the two unsaturated surfactants methyl oleate and oleic acid and three binary mixtures (including saturated stearic acid) exposed to NO3. The newly added method of in-situ infra-red spectroscopy will allow us not only to understand how the interaction between the two components affects the oxidation reaction and its rate coefficient, but also to directly identify reaction products at the air-water interface.