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Quantifying the importance of the atmospheric sink for polychlorinated dioxins and furans relative to other global loss processes.

Lohmann, Rainer and Jurado, Elena and Dachs, Jordi and Lohmann, Ulrike and Jones, Kevin C. (2006) Quantifying the importance of the atmospheric sink for polychlorinated dioxins and furans relative to other global loss processes. Journal of Geophysical Research: Atmospheres, 111 (D21303). ISSN 0747-7309

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    Abstract

    Previous attempts to establish global mass balances for polychlorinated dioxins and furans (PCDD/Fs) have focused on the terrestrial sink, thereby neglecting deposition to the oceans and atmospheric losses. In this study, the atmospheric sink of polychlorinated dioxins and furans (PCDD/Fs) was calculated on the basis of their presence in soils. OH radical ([OH]) depletion reactions compete with atmospheric deposition fluxes for the fate of atmospheric PCDD/Fs. Three different steady state scenarios were considered: scenario A was a one-box atmosphere with globally averaged [OH], temperature (T), atmospheric lifetime (tlife), and a constant gas-particle partitioning (Φ); in scenario B, [OH], T, and Φ were averaged in a multibox atmosphere, with a constant tlife; and in scenario C, tlife was varied. In scenario A the strength of the atmospheric sink was 2400–2800 kg/yr; in scenario B it was ∼2100 kg/yr; in scenario C, it was ∼1,800 kg/yr (tlife = 5.4 days) to ∼2,800 kg/yr (tlife = 14 days). The majority of the atmospheric sink was due to the depletion of Cl4DFs (1300–1400 kg/yr), followed by Cl4DDs (360–380 kg/yr) and Cl5DFs (230–240 kg/yr). On a global scale, major sinks for PCDD/Fs are the deposition to terrestrial soils and the oceans. For Cl6–8DDs, deposition to soils outweighs depletion reactions in the atmosphere and ocean uptake. The more volatile Cl4–5DD/Fs, however, are true “multimedia” compounds, with their estimated atmospheric sink being roughly as important as the terrestrial sink (in the case of Cl5DD/Fs) or outweighing it (e.g., Cl4DD/Fs).

    Item Type: Article
    Journal or Publication Title: Journal of Geophysical Research: Atmospheres
    Additional Information: Copyright (2006) American Geophysical Union. Further reproduction or electronic distribution is not permitted
    Uncontrolled Keywords: dioxins and furans ; OH radical depletion ; gas-particle partitioning
    Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 8807
    Deposited By: Ms Margaret Calder
    Deposited On: 13 May 2008 09:49
    Refereed?: Yes
    Published?: Published
    Last Modified: 17 Sep 2013 08:24
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/8807

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