The study of the formation and molecular chemical composition of SOA is critical because of their influence on climate through cloud formation and the radiative forcing of SOA. An understanding of SOA composition is beneficial for the improvement of air quality models, given that SOA are a major component of fine particulate matter (PM2.5). Furthermore, changes in VOC emissions resulting from expected future increase in biomass burning events and shifts in energy production and usage also alter the composition and pathways of SOA formation. Consequently, it is important to understand these dynamics in order to accurately predict their impact on air quality, climate, and human health (e.g. respiratory and cardiovascular diseases).

In our studies, we employ a range of advanced analytical techniques, including High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS) and Extractive Electrospray Ionization Long-Time-of-Flight Chemical Ionization Mass Spectrometry (EESI-LToF-CIMS). HR-ToF-AMS is employed to provide real-time, high-resolution data on the bulk chemical composition of aerosols including elemental ratios and oxidation states. EESI-LToF-CIMS provides an additional capability by enabling the sensitive detection of highly oxygenated organic molecules and low-volatile compounds directly online from the gas and particle phases without the necessity for extensive sample preparation or alteration. This allows a more complete picture of the complex chemical composition of SOA to be captured.

These analytical techniques are employed within controlled simulation environments, including the atmosphere simulation chamber SAPHIR, the Plant Unit for Simulation coupled to SAPHIR (SAPHIR-PLUS), and the Stirred Atmospheric Flow Reactor (SAPHIR-STAR). The SAPHIR chamber allows for the study of photochemical reactions and atmospheric processes under near-real atmospheric conditions, while SAPHIR-PLUS is specifically designed to study real biogenic emissions offering a unique opportunity to assess how plant-derived VOCs contribute to SOA formation under varying environmental conditions, including constitutive emissions, and emissions due to e.g. heat, drought or ozone stress. The SAPHIR-STAR chamber permits the investigation of SOA formation and gas-particle partitioning in a highly controlled environment and under steady-state conditions which is essential to understand critical chemical processes that drive and contribute to SOA formation. These investigations are carried out in close collaboration with the "Heterogeneous Reactions" group.

_{Banner image AI generated}