HR: 09:45h
AN: B31C-08    [Abstracts]
TI: Stable Carbon Isotope Characterization of Non-Methane Hydrocarbons in Vancouver and Toronto Airsheds
AU: MacIsaac, G
EM: gmacisaa@uvic.ca
AF: School of Earth and Ocean Sciences, E-Hut University of Victoria, Victoria, BC V8W 2Y2 Canada
AU: * Whiticar, M J
EM: whiticar@uvic.ca
AF: School of Earth and Ocean Sciences, E-Hut University of Victoria, Victoria, BC V8W 2Y2 Canada
AU: Rudolph, J
EM: rudolphj@yorku.ca
AF: Center for Atmospheric Chemistry, York Univeristy 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: Gao, S
EM: rudolphj@yorku.ca
AF: Center for Atmospheric Chemistry, York Univeristy 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AB: We have developed an approach using stable carbon isotopes as tool to understanding distribution and free radical chemistry of Volatile Organic Compounds (VOCs) in urban airsheds. Carbon isotope ratios are indirect tracers for the reactions of non-methane hydrocarbons (NMHC) with OH radicals. The carbon isotope signatures are diagnostic of the source inputs and trajectories and potentially fingerprint emissions. Compound Specific Isotope Analyses (CSIA) by Continuous Flow-Isotope Ratio Mass Spectrometry (CF-IRMS) of NMHC were made on ambient air samples from urban, suburban, rural and source sites in the airsheds of Toronto and Vancouver, Canada. The extent of chemical processing due to OH radical reactions that the individual NMHC has experienced since emission is quantitatively determined. In combination with concentration measurements it is shown that isotope ratio measurements are an extremely valuable new tool for studying spatial and temporal differences in chemical removal mechanisms, mixing and dilution processes.
UR: http://www.biogeochemistry.uvic.ca
DE: 1694 Instruments and techniques
DE: 1040 Isotopic composition/chemistry
DE: 1055 Organic geochemistry
DE: 0317 Chemical kinetic and photochemical properties
DE: 0322 Constituent sources and sinks
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting