Estimation of CFC-11 emissions from coal combustion in China

The trichlorofluoromethane (CFC-11) emission from its production and use (PAU) has drawn widespread interest, while its combustion sources have been overlooked. This study identified CFC-11 emission factors (EFs) of 3.6, 3.2 and 0.025 mg kg−1 from the combustion of domestic chunk coal, honeycomb briquettes and coal-fired power plants, respectively. A multi-year (2000–2021) emission inventory of CFC-11 from coal combustion in China was established. Results indicated that the CFC-11 annual emission from coal combustion in China was, on average, 233.5 t yr−1. It exhibited fluctuations and maintained an overall upward trend, accounting for 0.8 % of PAU emissions in 2000 and increasing to 9.8 % in 2021, with the peak value appearing in 2016. In the Shandong and Hebei provinces, which have high coal consumption amounts, the CFC-11 emissions from coal combustion increased by approximately 74 % during 2014–2017 compared to 2011–2012. At the Gosan station close to the Chinese mainland, CFC-11 emitted from coal combustion in Hebei and Shandong was 0.5 ppt of its average concentration during January 2016. An additional climate effect of the clean heating and coal-to-electricity policies in China was also observed, with an obvious decrease (2.2 × 106 and 3.4 × 107 t) in CO2-equivalent emission. This study provides substantial evidence of CFC-11 emission from coal combustion and highlights the role of combustion emission against the background of reducing CFC-11 from PAU. The data compiled in this work can be found at https://doi.org/10.6084/m9.figshare.28523063 (Niu et al., 2025).