Current sources of carbon tetrachloride (CCl4) in our atmosphere

Carbon tetrachloride (CCl _4 or CTC) is an ozone-depleting substance whose emissive uses are controlled and practically banned by the Montreal Protocol (MP). Nevertheless, previous work estimated ongoing emissions of 35 Gg year ^−1 of CCl _4 into the atmosphere from observation-based methods, in sta...

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Bibliographic Details
Main Authors: David Sherry, Archie McCulloch, Qing Liang, Stefan Reimann, Paul A Newman
Format: Article
Language:English
Published: IOP Publishing 2018-01-01
Series:Environmental Research Letters
Subjects:
Online Access:https://doi.org/10.1088/1748-9326/aa9c87
Description
Summary:Carbon tetrachloride (CCl _4 or CTC) is an ozone-depleting substance whose emissive uses are controlled and practically banned by the Montreal Protocol (MP). Nevertheless, previous work estimated ongoing emissions of 35 Gg year ^−1 of CCl _4 into the atmosphere from observation-based methods, in stark contrast to emissions estimates of 3 (0–8) Gg year ^−1 from reported numbers to UNEP under the MP. Here we combine information on sources from industrial production processes and legacy emissions from contaminated sites to provide an updated bottom-up estimate on current CTC global emissions of 15–25 Gg year ^−1 . We now propose 13 Gg year ^−1 of global emissions from unreported non-feedstock emissions from chloromethane and perchloroethylene plants as the most significant CCl _4 source. Additionally, 2 Gg year ^−1 are estimated as fugitive emissions from the usage of CTC as feedstock and possibly up to 10 Gg year ^−1 from legacy emissions and chlor-alkali plants.
ISSN:1748-9326