AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Organosulfate Formation from 2-Methyl-3-Buten-2-ol (MBO) as a Secondary Organic Aerosol (SOA) Tracer in the Atmosphere
HAOFEI ZHANG, David Worton, Michael Lewandowski, John Ortega, Caitlin Rubitschun, Kasper Kristensen, Pedro Campuzano-Jost, Douglas Day, Jose-Luis Jimenez, Mohammed Jaoui, John Offenberg, Tadeusz Kleindienst, Jessica Gilman, Joost de Gouw, Chang Hyoun Park, Gunnar Schade, Amanda Frossard, Lynn Russell, Marianne Glasius, Alex Guenther, Allen H. Goldstein, John Seinfeld, Avram Gold, Richard Kamens, Jason Surratt, University of North Carolina at Chapel Hill
Abstract Number: 263 Working Group: Aerosol Chemistry
Abstract 2-methyl-3-buten-2-ol (MBO) is an important biogenic volatile organic compound (BVOC) emitted by pine trees and a potential precursor of atmospheric secondary organic aerosol (SOA) in forested regions. In the present study, hydroxyl radical (OH)-initiated oxidation of MBO was examined in smog chambers under varied initial nitric oxide (NO) and aerosol acidity levels. Results indicate measureable SOA from MBO under low-NO conditions. Moreover, increasing aerosol acidity was found to enhance MBO SOA. Chemical characterization of laboratory-generated MBO SOA reveals that an organosulfate species (C$_5H$_(12)O6$_S, MW 200) formed and was substantially enhanced with elevated aerosol acidity. Ambient fine aerosol (PM$_(2.5)) samples collected from the BEARPEX campaign during 2007 and 2009, as well as from the BEACHON-RoMBAS campaign during 2011, were also analyzed. The MBO-derived organosulfate characterized from laboratory-generated aerosol was observed in PM$_(2.5) collected from these campaigns, demonstrating that it is a molecular tracer for MBO-initiated SOA in the atmosphere. Furthermore, mass concentrations of the MBO-derived organosulfate are well correlated with MBO mixing ratio, temperature, and acidity in the field campaigns. Importantly, this compound accounted for an average of 0.25% and as high as 1% of the total organic aerosol mass during BEARPEX 2009. An epoxide intermediate generated under low-NO conditions is tentatively proposed to produce MBO SOA.