Investigation on the formation mechanism of secondary organic aerosol in isoprene ozonolysis by chemical ionization mass spectrometry

Abstract

To estimate gas-aerosol partitioning of semi-volatile organic compounds (SVOC) produced in oxidation processes, we detected and quantified SVOC in both gaseous and aerosol phases by proton transfer reaction mass spectrometry (PTR-MS). We investigated the isoprene ozonolysis reaction using a 6 m⁶ smog chamber under dry conditions and without seed particles. Gaseous reactants and products were monitored by FT-IR and PTR-MS. After 2 hour, the formed SOA was collected on the PTFE filter and was analyzed by PTR-MS. In addition to the smog chamber experiments, similar experiments were carried out using a 1 m³ Teflon bag in order to compare PTR-MS data with negative ion-chemical ionization mass spectrometer (NI-CIMS) data.