Increase in CFC-11 emissions from eastern China based on atmospheric observations

Area of Science:

• Atmospheric chemistry and environmental science.
• Ozone layer protection and climate change mitigation.

Background:

• Stratospheric ozone layer recovery depends on decreasing ozone-depleting gases like chlorofluorocarbons (CFCs).
• Atmospheric concentrations of CFC-11, a major CFC, declined until recently, but a slowdown suggests increased global emissions.
• A rise in CFC-11 emissions from East Asia was noted, but the source region and scale remained unknown.

Purpose of the Study:

• To investigate and pinpoint the regional source and magnitude of increased CFC-11 emissions in East Asia.
• To determine the contribution of East Asian emissions to the global increase in CFC-11.
• To assess compliance with the Montreal Protocol regarding CFC production and use.

Main Methods:

• Utilized high-frequency atmospheric observations from South Korea and Japan.
• Integrated global monitoring data with atmospheric chemical transport model simulations.
• Analyzed CFC-11 emission changes between 2008-2012 and 2014-2017.

Main Results:

• Identified significant CFC-11 emissions from eastern mainland China, 7.0 ± 3.0 Gg/year higher in 2014-2017 than 2008-2012.
• Localized the emission increase primarily to the Shandong and Hebei provinces in northeastern China.
• Determined that these Chinese emissions accounted for 40-60% of the global CFC-11 emission rise.
• Found no evidence of significant CFC-11 emission increases from other East Asian countries or other monitored global regions.

Conclusions:

• The increase in CFC-11 emissions from eastern China is likely due to new production and usage.
• This finding contradicts the Montreal Protocol's phase-out of global CFC production by 2010.
• Further monitoring is needed to attribute the remaining global CFC-11 emission rise due to sparse data in potential source regions.