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Abstract
Climate change may be one of the most important puzzles the world has attempted to solve and one of the greatest challenges in this area is to improve our understanding of how atmospheric aerosol particles impact climate processes. We seek to overcome this challenge by focusing on the chemistry and formation mechanisms of secondary organic aerosol (SOA) particles, a key group of aerosol particles that are produced on a massive scale by the world’s large forest ecosystems via the oxidation of biogenic volatile organic compounds (BVOCs). SOA particles make up a substantial fraction of tropospheric aerosols and are known to lead to atmospheric cooling. However, their formation ranks among the least understood chemical processes in the atmosphere, due in part to a lack of information regarding chemical composition, particularly at the gas/aerosol interface. In addition, lack of access to authentic standards of aerosol oxidation products has led to difficulties in the identification, quantification and determination of the physical properties of SOA constituents in the atmospheric community.
In this work, molecular constituents of SOA particles are characterized through the synthesis of authentic standards of oxidation products and isotopologues of BVOCs. The combination of surface-selective techniques, such as sum frequency generation (SFG) spectroscopy, with organic synthesis allows us to gain molecular-level insight into BVOCs and their oxidation products, enhancing our understanding of SOA formation and surface composition. The observed surface activity of these products may have important implications for cloud condensation nuclei (CCN) activity and aerosol growth. In addition, generation of SOA material derived from isotopologues of BVOCs has led to the identification of important surface-active groups present in SOA material. Collaborations with the atmospheric research community has not only led to the use of synthetic standards in studies investigating the formation mechanisms and physical properties of SOA particles, but has also provided access to field SOA samples for analysis using surface-specific SFG spectroscopy.
