Abstract: Secondary aerosol particles in the atmosphere originate from low-volatility vapors. Different environments are characterized by their own multicomponent system driving the process of molecular clustering and their subsequent growth in size. With specific focus on determining the role of oxygenated organics in particle formation, we conduct targeted laboratory and field studies. In this talk, I will present the results of measurements conducted in remote and urban environments, underlining the importance of meteorology and our ability to quantify oxidized organics as well as discuss future research directions.