Apportionment of natural versus anthropogenic sources of halocarbons depleting Arctic ozone: Novel applications of powerful halocarbon-specific analysis of d37Cl, d81Br and D14C isotopes
Person photo Prof Örjan Gustafsson
Department of Environmental Science and Analytical Chemistry

Funding source: Swedish Research Council - Vetenskapsr├ądet (VR)
Period: 1/1/08 - 12/31/10
Funding: 7500000 SEK
Halogenated volatile organic compounds (HVOC) such as CH3Br, CH3Cl and CHBr3 have a mix of natural and anthropogenic sources and stand for a poorly constrained contribution (25-50%?) of halogen-induced ozone depletion in the Arctic atmosphere. Source-diagnostic dual-isotopic fingerprint of these HVOC in high-Arctic air will enable a completely new approach for distinct source apportionment. A new dual-stage cryogenic sampler will collect Arctic air HVOC on Zeppelin Mtn (Svalbard 79N) and HVOC from sources such as polar marine microorganism/macroalgae, snow/ice, and emanating from peatland and thawing permafrost near Abisko (N. of Arctic Circle). Determination of the d37Cl, d81Br, and D14C fingerprint of HVOC from marine, terrestrial, and anthropogenic sources will allow constraining the contribution of each to Arctic air by solving a set of isotopic mass balance equations. Two applicant groups hold unique competence in compound-specific isotope analysis (CSIA) of Cl, Br and 14C isotopes. Existing CSIA methods for halogenated semivolatile organic compounds (HSOC) will be adapted to allow these first CSIA of HVOC. Two other applicants have expertise in HVOC emissions and sampling from marine and terrestrial sources, respectively. With increasing Arctic ozone depletion and uncertain links to climate warming, the project will provide information what anthropogenic sources to target for reduction and what natural sources to account for in predictions of future ozone depletion.
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Prof Patrick Crill
Department of Geological Sciences