AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Characterization of Highly Oxidized Multifunctional Species (HOM) Generated from the Oxidation of α-pinene Using High-resolution Time-of-Flight Chemical Ionization Mass Spectrometry (HR-ToF-CIMS)
PENGLIN YE, Andrew Lambe, Chao Yan, Wei Nei, Paola Massoli, Manjula Canagaratna, John Jayne, Douglas Worsnop, Aerodyne Research, Inc.
Abstract Number: 469 Working Group: Aerosol Chemistry
Abstract Highly oxidized multifunctional (HOM) species that are generated in the gas phase from the oxidation of biogenic and anthropogenic precursors play an important role in new particle formation and growth. However, the relative contribution to HOMs formation from different oxidation pathways remains poorly understood. Using α-pinene as a biogenic surrogate species, we characterize the chemical compositions and relative yields of HOMs along with other oxidation products that are formed following oxidation initiated by O3, hydroxyl (OH) radicals or nitrate (NO3) radicals in a Potential Aerosol Mass (PAM) oxidation flow reactor. We use a high-resolution time-of-flight chemical-ionization mass spectrometer with I- as the primary reagent ion coupled to a filter inlet for gases and aerosols (FIGAERO I-CIMS) to measure the elemental composition of HOM molecules in both vapor and particle phases. A subset of these CIMS measurements are also conducted with NO3- as the reagent ion to further characterize more oxidized gas-phase HOMs. PAM reactor operating conditions are systematically varied in order to characterize HOM signatures as a function of integrated oxidant exposure and ratio of nitric oxide (NO) to hydroperoxyl (HO2) radical. We additionally compare laboratory CIMS signatures with ambient CIMS measurements obtained in a boreal forest.