Atmospheric Fate and Impact of Perfluorinated Butanone and Pentanone

Perfluoroketones, used as replacement to halons and CFCs, are excluded from the Montreal Protocol because they are considered as nonozone depleting substances. However, their chemical structure makes them possible greenhouse gases if their atmospheric lifetimes are long enough. To assess that possib...

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Bibliographic Details
Published in:Environmental science & technology 2019-08, Vol.53 (15), p.8862-8871
Main Authors: Ren, Yangang, Bernard, François, Daële, Véronique, Mellouki, Abdelwahid
Format: Article
Language:English
Subjects:
Chlorofluorocarbons
Climate change
Environmental policy
Environmental Sciences
Fluorination
Global warming
Greenhouse effect
Greenhouse gases
Halons
International agreements
Montreal Protocol
Organic chemistry
Oxidants
Oxidizing agents
Pentanone
Perfluoro compounds
Photolysis
Troposphere
Vapor phases
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Summary:Perfluoroketones, used as replacement to halons and CFCs, are excluded from the Montreal Protocol because they are considered as nonozone depleting substances. However, their chemical structure makes them possible greenhouse gases if their atmospheric lifetimes are long enough. To assess that possibility, we investigated the photolysis of perfluoro-2-methyl-3-pentanone (PF-2M3P), and perfluoro-3-methyl-2-butanone (PF-3M2B) using outdoor atmospheric simulation chambers. In addition, the photolysis of a non fluorinated pentanone (2-methyl-3-pentanone, 2M3P) was studied. The results showed that photolysis is the dominant loss pathway of PF-2M3P and PF-3M2B in the troposphere whereas 2M3P is lost by both photolysis and gas phase reaction with atmospheric oxidants. The photolysis effective quantum yields of PF-2M3P, PF-3M2B, and 2M3P were estimated and some of the main products identified. The photolysis of PF-2M3P and PF-3M2B was found to have a minor impact on the atmospheric burden of fluorinated acids. The atmospheric lifetimes of PF-2M3P, PF-3M2B, and 2M3P were estimated to 3–11 days, ∼13 days, and 1–2 days, respectively. Combining the obtained data, it has been concluded that with 100-year time horizon global warming potentials (GWP100) equivalent to
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.9b02974