10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Chemical Composition of Secondary Organic Aerosol Generated from Emissions of California Sage Plants Using a FIGAERO-ToF-CIMS
ARCHIT MEHRA, Jordan Krechmer, Andrew Lambe, Chinmoy Sarkar, Leah Williams, Fatemeh Khalaj, James Allan, John Jayne, Hugh Coe, Douglas Worsnop, Celia Faiola, Manjula Canagaratna, University of Manchester
Abstract Number: 338 Working Group: Oxidation Flow Reactor: Development, Characterization, and Application to Aerosols
Abstract Emissions from plants are the main source of atmospheric biogenic volatile organic compounds (BVOCs). Oxidation of BVOCs under ambient conditions results in formation of more oxidised species, many of which have lower volatility than their precursors. These species can partition into the particle phase and contribute to secondary organic aerosol (SOA) formation. To date, the majority of laboratory biogenic SOA experiments have been focused on single or simple multi-component BVOC mixtures that are thought to be representative of Northern Hemispheric deciduous or mixed forest conditions; thus, gaps remain in our understanding of SOA formation from complex mixtures of real plant emissions in other environments. Towards the goal of understanding SOA formation of plant emissions in other source regions, we conducted a series of experiments where Black Sage (Salvia mellifera) and California Sagebrush (Artemisia californica) plant emissions (the most common plant species in southern California’s coastal sage ecosystem) were oxidised in an Aerodyne Potential Aerosol Mass Oxidation Flow Reactor. The chemical composition and the volatility of the SOA were probed with a high-resolution time-of-flight chemical-ionization mass spectrometer equipped with a Filter Inlet for Gases and AEROsols (FIGAERO-ToF-CIMS). Chemical ionization was performed with the iodide reagent ion, which is sensitive to multifunctional oxidized species. Single-BVOC oxidation experiments were also performed with eucalyptol, camphor and camphene, which are the major constituents of the Sage plant emissions. Positive Matrix Factorisation of the FIGAERO-ToF-CIMS mass spectra was used to identify contributions of the individual VOCs to the emission profile of SOA generated from oxidation of the plant emissions. FIGAERO thermograms of SOA generated from standards and the real plant mixture will be presented with the PMF factor results and data interpretation.