Observations and potential source regions of HFC-152a in southeastern China

Under the global HFCs reduction framework of the Kigali Amendment (KA) to the Montreal Protocol (MP), although HFC-152a is widely used as an ozone-friendly alternative in fields such as refrigeration and foam blowing agents, its production volume has gradually increased in recent years, prompting regulatory attention. In this study, we conducted a continuous daily in-situ observation of HFC-152a at a remote site in southeastern China from May 2023 to May 2024. HFC-152a exhibits seasonal variations in mixing ratios and enhancements, with summer values being lower than in other seasons. During the observation period, the average mixing ratio was 13.6 ± 5.2 ppt, while the average enhancement was 5.8 ± 4.1 ppt. The Yangtze River Delta, eastern and northern Jiangxi, the border between Jiangxi and Fujian, and the coastal areas of Fujian were identified as the primary potential source regions of HFC-152a by employing the Potential Source Contribution Function (PSCF) and the Concentration Weighted Trajectory (CWT) methods. Moreover, using the interspecies correlation (ISC) method with trichloromethane (CHCl₃) and difluoromethane (HFC-32) as tracers, the estimated emissions of HFC-152a in southeastern China were found to be 2.5 ± 1.0 Gg/yr and 2.0 ± 0.7 Gg/yr, respectively. The estimated emissions of HFC-152a in the Yangtze River Delta were found to be 1.6 ± 0.6 Gg/yr and 1.2 ± 0.4 Gg/yr, respectively. This study provides an understanding of the characteristics and potential source regions of HFC-152a in southeastern China.