HR: 1330h
AN: A52A-0775    [PDF]
TI: Laboratory Studies of Stable Hydrogen Kinetic Isotope Effects for Reactions of Non-methane Hydrocarbons (NMHCs) With OH, Ozone, and Cl in the Gas Phase and Their Relevance for Studies of NMHCs in the Atmosphere
AU: Iannone, R
EM: riannone@yorku.ca
AF: Centre for Atmospheric Chemistry, Department of Chemistry York University 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: * Anderson, R S
EM: rebeccah@yorku.ca
AF: Centre for Atmospheric Chemistry, Department of Chemistry York University 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: Vogel, A
EM: aileen@yorku.ca
AF: Centre for Atmospheric Chemistry, Department of Chemistry York University 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: Rudolph, J
EM: rudolphj@yorku.ca
AF: Centre for Atmospheric Chemistry, Department of Chemistry York University 4700 Keele Street, Toronto, ON M3J 1P3 Canada
AU: Eby, P
EM: peby@uvic.ca
AF: Biogeochemistry Facility, School of Earth and Ocean Sciences University of Victoria 3800 Finnerty Road, Victoria, BC V8P 5C2 Canada
AU: Whiticar, M J
EM: whiticar@uvic.ca
AF: Biogeochemistry Facility, School of Earth and Ocean Sciences University of Victoria 3800 Finnerty Road, Victoria, BC V8P 5C2 Canada
AB: During the last few years it has been shown that measurements of stable carbon isotope ratios of non-methane hydrocarbons (NMHCs) in the troposphere are useful for better understanding their sources, sinks, and distributions, and to quantify the extent of atmospheric processing of the studied NMHC. The ability to interpret atmospheric stable isotope ratio measurements of NMHCs depends on the knowledge of the stable isotope ratios of the emissions and the understanding of the isotope fractionation associated with the atmospheric NMHC removal processes. It seems reasonable that stable hydrogen isotope ratio measurements can serve a similar purpose; however, there is presently little information on isotope fractionations for reactions of NMHCs with close to natural stable hydrogen isotope abundance. Here we present the results of laboratory measurements of stable hydrogen kinetic isotope effects for some of the most important atmospheric removal reactions of NMHCs, namely the reaction with the OH radical, O$_{3}$, and the Cl atom. Based on these results, we predict that for many NMHCs, especially the alkanes, atmospheric reactions will cause substantial and significant changes in stable hydrogen isotope ratios. It is also demonstrated that combining measurements of stable hydrogen and stable carbon isotope ratios of atmospheric NMHCs has a very high potential to reduce uncertainties in estimates of the extent of photochemical NMHC processing and to reduce uncertainties resulting from variability of stable isotope ratios of emissions.
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
DE: 0394 Instruments and techniques
DE: 1040 Isotopic composition/chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting