Understanding semivolatile organic compounds in remote and urban atmospheres, Prof. Arthur Chan, UofT

Professor Arthur Chan, Chemical Engineering and Applied Chemistry, University of Toronto

Guest Speaker:  Professor Arthur Chan, Chemical Engineering and Applied Chemistry, University of Toronto
Description:  Constraining sources of organic aerosol is important for global climate and human health. There is increasing evidence that semivolatile organic compounds (SVOCs) and their oxidation products are highly reactive and can be a dominant source of organic aerosol. Identifying and quantifying SVOCs is difficult, often limited by sampling losses and insufficient separation capabilities. Here we use a newly developed instrument that quantitatively analyzes SVOCs on a bihourly timescale. We deployed this instrument in a pine forest, and show that many SVOCs are biogenically derived, and they dominate reactive loss of ozone. We have also developed a method combining chromatographic separation with vacuum ultraviolet photoionization to analyze hydrocarbon isomers in a complex organic mixture, speciating alkanes by their molecular structures (carbon number, alkyl branching and number of rings/double bonds). This method was applied to understanding the photochemical processing of vehicular emissions in California during the Calnex 2010 field campaign. Continuing instrument development will also be discussed.