Atmospheric secondary organic aerosol formation is not completely understood, aerosol processes and chemistry are complex as well as their interactions and evolution throughout the atmosphere. In this study the potential aerosol mass chamber was used to simulate these processes. Potential aerosol mass being the maximum mass that can be produced from precursor gases being oxidised. UV lamps situated inside the chamber produce oxidants (O3, OH, HO2) at the same ratio as the atmosphere and the lamp intensity can be changed to simulate different days of photochemical aging. Laboratory characterisation measurements were undertaken by adjusting various experimental parameters (level of oxidants, relative humidity, temperature, type of precursor and its concentration). The aim of these measurements is to understand how the PAM chamber simulates atmospheric aerosol aging and photochemical processes. The PAM chamber was observed to simulate atmospheric SOA formation well. As the amount of oxidants was increased the amount of formed SOA increased initially. After a certain point, it was observed that fragmentation started to decrease the mass even though the oxidation level of SOA increased further.
