Anthropogenic emissions of ozone-depleting substance CHCl during 2000-2020 in China.

Methyl Chloride (CHCl) is the largest source of stratospheric chlorine, which has a significant impact on the depletion of the stratospheric ozone layer. Detailed information on anthropogenic CHCl emissions in China is still lacking. This study establishes a comprehensive bottom-up inventory of anthropogenic CHCl emissions in China during 2000-2020. Results show that China's anthropogenic CHCl emissions have increased significantly, from 34.1 ± 11.6 Gg/yr (gigagrams per year) in 2000 to 128.5 ± 26.5 Gg/yr in 2018 with a slight decrease to 124.9 ± 26.0 Gg/yr in 2020. The main sources of anthropogenic emissions of CHCl in China are chemical production (37.1%), solvent use (35.4%), and coal combustion (13.6%) in 2020. China's contribution to global anthropogenic emissions of CHCl reached almost 50%. Moreover, the ratios of CHCl CFC-11-eq emissions relative to emissions of ozone-depleting substances (ODSs) controlled under the Montreal Protocol in China have increased from 0.8% in 2000 to 11.6% in 2020 and are estimated to continue increasing in the future. In summary, China's anthropogenic CHCl emissions have shown an increasing trend in the past two decades, made a huge contribution to the total global anthropogenic emissions, and presented a potential increasing impact on the depletion of the ozone layer and global warming.