Substantial increase in perfluorocarbons CF₄ (PFC-14) and C₂F₆ (PFC-116) emissions in China.

Abstract

The perfluorocarbons tetrafluoromethane (CF₄, PFC-14) and hexafluoroethane (C₂F₆, PFC-116) are potent greenhouse gases with near-permanent atmospheric lifetimes relative to human timescales and global warming potentials thousands of times that of CO₂. Using long-term atmospheric observations from a Chinese network and an inverse modeling approach (top-down method), we determined that CF₄ emissions in China increased from 4.7 (4.2-5.0, 68% uncertainty interval) Gg y^-1 in 2012 to 8.3 (7.7-8.9) Gg y^-1 in 2021, and C₂F₆ emissions in China increased from 0.74 (0.66-0.80) Gg y^-1 in 2011 to 1.32 (1.24-1.40) Gg y^-1 in 2021, both increasing by approximately 78%. Combined emissions of CF₄ and C₂F₆ in China reached 78 Mt CO₂-eq in 2021. The absolute increase in emissions of each substance in China between 2011-2012 and 2017-2020 was similar to (for CF₄), or greater than (for C₂F₆), the respective absolute increase in global emissions over the same period. Substantial CF₄ and C₂F₆ emissions were identified in the less-populated western regions of China, probably due to emissions from the expanding aluminum industry in these resource-intensive regions. It is likely that the aluminum industry dominates CF₄ emissions in China, while the aluminum and semiconductor industries both contribute to C₂F₆ emissions. Based on atmospheric observations, this study validates the emission magnitudes reported in national bottom-up inventories and provides insights into detailed spatial distributions and emission sources beyond what is reported in national bottom-up inventories.