Method development of a denuder based technique for the determination of the partitioning of nitrophenols

The formation of secondary organic matter (SOM), from the photooxidation of aromatic volatile organic compounds is currently quite poorly understood. One class of these secondary organic species are nitrophenols, which are formed in the atmosphere from the hydroxyl radical initiated photooxidation of aromatic hydrocarbons. Due to their semi-volatile nature, nitrophenols exist in the atmosphere in both the gas phase and in particulate matter (PM), which makes understanding their partitioning important in order to gain a better understanding of the formation, yields and processing of SOM. In this work, an application was developed for the IOGAPS (Integrated Organic Gas and Particle Sampler) system to determine concentration measurements for both gas phase and PM for a group of five nitrophenols in the atmosphere. These nitrophenols were found to exist predominately in the gas phase, with their partitioning between the two phases showing only slight dependences on ambient temperature and saturation vapor pressure.