A rise in HFC-23 emissions from eastern Asia since 2015

Park, H., Kim, J., Choi, H., Geum, S., Kim, Y., Thompson, R. L., Mühle, J., Salameh, P. K., Harth, C. M., Stanley, K. M., O'Doherty, S., Fraser, P. J., Simmonds, P. G., Krummel, P. B., Weiss, R. F., Prinn, R. G., and Park, S.: A rise in HFC-23 emissions from eastern Asia since 2015, Atmos. Chem. Phys., 23, 9401–9411, https://doi.org/10.5194/acp-23-9401-2023, 2023.
Atmospheric Chemistry and Physics, Park, H., Kim, J., Choi, H., Geum, S., Kim, Y., Thompson, R. L., Mühle, J., Salameh, P. K., Harth, C. M., Stanley, K. M., O'Doherty, S., Fraser, P. J., Simmonds, P. G., Krummel, P. B., Weiss, R. F., Prinn, R. G., and Park, S.: A rise in HFC-23 emissions f
2023
Abstract

Trifluoromethane (CHF3, HFC-23), one of the most potent greenhouse gases among hydrofluorocarbons (HFCs), is mainly emitted to the atmosphere as a by-product in the production of the ozone-depleting legacy refrigerant and chemical feedstock chlorodifluoromethane (CHClF2, HCFC-22). A recent study on atmospheric observation-based global HFC-23 emissions (top-down estimates) showed significant discrepancies over 2014–2017 between the increase in the observation-derived emissions and the 87 % emission reduction expected from capture and destruction processes of HFC-23 at HCFC-22 production facilities implemented by national phase-out plans (bottom-up emission estimates) (Stanley et al., 2020). However, the actual regions responsible for the increased emissions were not identified. Here, we estimate the regional top-down emissions of HFC-23 for eastern Asia based on in situ measurements at Gosan, South Korea, and show that the HFC-23 emissions from eastern China have increased from 5.0±0.4 Gg yr−1 in 2008 to 9.5±1.0 Gg yr−1 in 2019. The continuous rise since 2015 was contrary to the large emissions reduction reported under the Chinese hydrochlorofluorocarbons production phase-out management plan (HPPMP). The cumulative difference between top-down and bottom-up estimates for 2015–2019 in eastern China was 

 Gg, which accounts for 47±11 % of the global mismatch. Our analysis based on HCFC-22 production information suggests the HFC-23 emissions rise in eastern China is more likely associated with known HCFC-22 production facilities rather than the existence of unreported, unknown HCFC-22 production, and thus observed discrepancies between top-down and bottom-up emissions could be attributed to unsuccessful factory-level HFC-23 abatement and inaccurate quantification of emission reductions.