HR: 1340h
AN: A33A-0830    [Abstracts]
TI: Insights into the Sources and Chemical Processes of Submicron Aerosol at the Whistler Summit, BC based on Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometry
AU: * Zhang, Q
EM: qz@asrc.cestm.albany.edu
AF: ASRC, SUNY-Albany, Atmospheric Sciences Research Center, State University of New York, University at Albany, Albany, NY 12203, United States
AU: Sun, Y
AF: ASRC, SUNY-Albany, Atmospheric Sciences Research Center, State University of New York, University at Albany, Albany, NY 12203, United States
AU: Leaitch, R
AF: Environmental Canada, Environmental Canada, Toronto, ON M3H 5T4, Canada
AU: Macdonald, A
AF: Environmental Canada, Environmental Canada, Toronto, ON M3H 5T4, Canada
AU: Hayden, K
AF: Environmental Canada, Environmental Canada, Toronto, ON M3H 5T4, Canada
AU: Li, S
AF: Environmental Canada, Environmental Canada, Toronto, ON M3H 5T4, Canada
AU: Liggio, J
AF: Environmental Canada, Environmental Canada, Toronto, ON M3H 5T4, Canada
AU: Steffen, A
AF: Environmental Canada, Environmental Canada, Toronto, ON M3H 5T4, Canada
AU: van Donkelaar, A
AF: Dalhousie University, Dalhousie University, Halifax, NS M3H 5T4, Canada
AU: Martin, R
AF: Dalhousie University, Dalhousie University, Halifax, NS M3H 5T4, Canada
AU: Worsnop, D
AF: Aerodyne Research Inc., Aerodyne Research Inc., Billerica, MA 01821, United States
AU: Dunlea, E
AF: University of Colorado, University of Colorado, Boulder, CO 80309, United States
AU: Cubison, M
AF: University of Colorado, University of Colorado, Boulder, CO 80309, United States
AB: A new Time-of-Flight Aerosol Mass Spectrometer with a high mass resolution of ~ 5000 (HR-ToF-AMS; DeCarlo et al., Anal. Chem., 2006) was deployed at the summit of the Whistler Mountain (elev. ~ 2200 m), British Columbia, in spring 2006, as part of the NASA INTEX-B mission. With this instrument, we determined the concentration, composition, and chemically speciated size distributions of non-refractory (NR) submicron particles (approximately PM1) every 5 minutes. We also obtained the highly m/z-resolved mass spectra, based on which the elemental composition of most small ion fragments (m/z <100 amu) was quantitatively determined. Organic aerosol (OA) prevailed at the Whistler summit accounting for ~ 50 per cent of the total NR-PM1 mass. Sulfate was usually less abundant than organics in NR-PM1 but episodes of strongly enhanced sulfate aerosol were observed. A major sulfate episode occurred on May 15, 2006, during which sulfate and ammonium contributed > 90 per cent of the NR-PM1 mass. This episode lasted for ~ 0.5 day and was followed by a high OA episode. The OA detected during the sulfate period are highly oxidized, with mass spectral similar to fulvic acid and estimated O to C ratio > 1. The high resolution mass spectra indicate significant structural differences in organic species between these two episodes. Simulations from a global model of oxidant-aerosol chemistry (GEOS-Chem), backtrajectory analysis, evolution of the size distributions of aerosol species, mass spectra analysis, and correlations with tracer pollutants (e.g., O3, CO, and mercury) support Asian influence during the high sulfate period, in contrast with regional biogenic and anthropogenic influences during the high organic period.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting