Improved bottom-up approach for estimating HCFC-141b emissions and reduction potential in China from 2000 to 2

Accurate assessment of HCFC-141b emission trends is critical for compliance with the Montreal Protocol and climate mitigation. However, substantial gaps persist between top-down and bottom-up estimates, and systematic methods for gridded emission calculation and validation remain lacking. To address these gaps, we refine the emission estimation methodology for polyurethane foams during the waste disposal stage and establish a framework for calculating and validating gridded HCFC-141b emissions based on emission factor method and NAME model. Using China as a case study, we develop and verify a gridded inventory during 2000-2024. Estimated cumulative emissions are 294.0 kt, 133.7 kt lower than the latest bottom-up estimate and align more closely with top-down emissions, narrowing the gap between the two methods to some extent. The refined method reduced the normalized maximum benefit between simulated and observed atmospheric concentrations, from -7.94% to -1.65%. China’s 2024 banks (560 kt) far exceed cumulative emission, indicating substantial future potential. Gridded results show emissions concentrated in eastern coastal regions. Under an accelerated phase-out scenario, cumulative HCFC-141b emissions during 2025-2060 could be reduced by 4,266.9 kt, equivalent to 469.4 kt CFC-11-eq and 3,336.7 Mt CO2-eq, underscoring the importance of early phase-out measures. This framework supports more accurate regional assessments of halogenated compound emissions and their environmental impacts.