Determining the Atmospheric Oxidation of Campholenic Aldehyde

Science Center, Bent Corridor

Flow Tube Chemical Mass Spectrometry (FT-CIMS) was used to investigate the oxidation of biogenic volatile organic chemicals (BVOCs), specifically campholenic aldehyde (CA), in order to determine the formation of an epoxide intermediate under atmospherically relevant conditions. A connection has been shown between the atmospheric oxidation of BVOCs and secondary organic aerosol (SOA) formation, and SOAs have been shown to affect air quality and climate change. Epoxides have been isolated as the possible oxidation intermediate due to their high reactivity, which increases the ability to condense into the aerosol phase. The chemical ionization detection method utilized both proton transfer as well as iodide ion transfer for identifying the oxidation products. The overall reaction mechanism includes an OH abstraction reaction pathway, as well as an addition reaction that leads to both ketodialdehyde and epoxide products. Although some areas of the reaction mechanism are still tentative, the new work is the first to identify the formation of CA oxidation products and the results indicate that atmospheric CA has the potential to form SOAs through its epoxide intermediate.