A decline in emissions of CFC-11 and related chemicals from eastern China.

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From: Nature(Vol. 590, Issue 7846)
Publisher: Nature Publishing Group
Document Type: Report
Length: 9,207 words
Lexile Measure: 1620L

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Abstract :

Emissions of ozone-depleting substances, including trichlorofluoromethane (CFC-11), have decreased since the mid-1980s in response to the Montreal Protocol.sup.1,2. In recent years, an unexpected increase in CFC-11 emissions beginning in 2013 has been reported, with much of the global rise attributed to emissions from eastern China.sup.3,4. Here we use high-frequency atmospheric mole fraction observations from Gosan, South Korea and Hateruma, Japan, together with atmospheric chemical transport-model simulations, to investigate regional CFC-11 emissions from eastern China. We find that CFC-11 emissions returned to pre-2013 levels in 2019 (5.0 [plus or minus] 1.0 gigagrams per year in 2019, compared to 7.2 [plus or minus] 1.5 gigagrams per year for 2008-2012, [plus or minus]1 standard deviation), decreasing by 10 [plus or minus] 3 gigagrams per year since 2014-2017. Furthermore, we find that in this region, carbon tetrachloride (CCl.sub.4) and dichlorodifluoromethane (CFC-12) emissions--potentially associated with CFC-11 production--were higher than expected after 2013 and then declined one to two years before the CFC-11 emissions reduction. This suggests that CFC-11 production occurred in eastern China after the mandated global phase-out, and that there was a subsequent decline in production during 2017-2018. We estimate that the amount of the CFC-11 bank (the amount of CFC-11 produced, but not yet emitted) in eastern China is up to 112 gigagrams larger in 2019 compared to pre-2013 levels, probably as a result of recent production. Nevertheless, it seems that any substantial delay in ozone-layer recovery has been avoided, perhaps owing to timely reporting.sup.3,4 and subsequent action by industry and government in China.sup.5,6. Atmospheric data and chemical-transport modelling show that CFC-11 emissions from eastern China have again decreased, after increasing in 2013-2017, and a delay in ozone-layer recovery has probably been avoided.

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Gale Document Number: GALE|A660665860