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. By carrying out experiments on single components, we learnt that the surface tension drops much faster than the surface excess, thus it is not possible to relate them satisfactorily. The next step is to move 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. This will allow us to understand how the interaction between the two components affects the oxidation reaction and its rate coefficient.