Surfaces coated with biogenic surfactants exposed to the atmosphere are ubiquitous and are commonly present on aerosol particles, cloud droplets, buildings, plants, and oceans. As shown in the past, photochemical reactions taking places at these air/water interfaces lead to unique chemical pathways, producing volatile organic compounds (VOCs) and leading to secondary organic aerosol formation. Here, photochemical processes at the air/water interface of fatty acids layer on water containing, or not, various photosensitizers were studied, demonstrating VOC production. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified. We suggested that fatty acids alone at the air water interface do, once irradiated, induce peroxy-radical chemistry. Indeed the presence of these peroxy radicals has now been revealed and quantified by interfacial chemical titration. In addition, the photochemical lifetime of such fatty acids on water has now been investigated by means of Langmuir through. Moreover, for solutions containing a photosensitizer and various inorganic salts, we observed in addition the emissions of various oxidants. For instance, for water mimicking salty water, various halogenated products and radicals have been observed by means of an online-APCI-HRMS. While in presence of nitrate anion, HONO formation seems to dominate. This presentation will present and discuss these finding, highlighting how photosensitizing may influence condensed phase chemistry in the troposphere.