After the Kigali Amendment (KA) came into effect, HCFC-22 plants are obliged to limit HFC-23 emissions. Therefore, the study of cost-effective mitigation pathways for HFC-23 is important for the sustainable implementation of KA in China and other HCFC-22 producing countries. This study constructed an inventory of HFC-23 by-production, emissions, and abatement for HCFC-22 plants in China from 2006 to 2020, and predicted the costs and climate benefits of HFC-23 abatement in China's compliance with the KA between 2021 and 2060. Results showed that HFC-23 emissions from HCFC-22 plants in China contributed about 60% of the growth in global atmospheric mole fraction of HFC-23 observed by Advanced Global Atmospheric Gases Experiment (AGAGE) from 2007 to 2020. Furthermore, China's cumulative HFC-23 abatement was about 109 kt (1613 Mt CO2-eq) from 2006 to 2019, accounting for 53% of total by-production, which allowed the global atmospheric mole fraction and radiative forcing of HFC-23 in 2020 to avoid an uplift of 9.2 × 10−9 and 1.7 mW m−2, respectively, contributing to climate change mitigation. Under the baseline of the Kigali Amendment, less emission (LE), and resource utilization (RU) scenarios, the cumulative HFC-23 abatement from 2021 to 2060 would be 683 ± 29 kt (10107 ± 431 Mt CO2-eq), 694 ± 29 kt (10277 ± 427 Mt CO2-eq), and 702 ± 29 kt (10385 ± 426 Mt CO2-eq), respectively. The cumulative net abatement costs for the KA, LE, and RU scenarios would be 5.0 ± 0.2, 2.9 ± 0.2, and −2.7 ± 0.2 billion CNY (2021 prices), respectively. In the future, applying resource utilization technology to reduce HFC-23 emissions can achieve both climate and economic benefits.

Using the source identification and classification methodology described in UNEP standardized toolkit for dioxin releases, combined with research data over the past decade, the production and release of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from 6 major sectors in China were inventoried from 2003 to 2020, and were projected until 2025 based on current control measures and relevant industrial plans. The results showed that after ratification of the Stockholm Convention, China’s production and release of PCDD/Fs began to decline after peaking in 2007, demonstrating the effectiveness of preliminary control measures. However, the continual expansion of manufacturing and energy sectors, along with the lack of compatible production control technology, reversed the declining trend of production after 2015. Meanwhile, the environmental release continued to decrease, but at a slower rate after 2015. If subject to current policies, production and release would remain elevated with an expanding gap in between. This study also established the congener inventories, revealing the significance of OCDF and OCDD in terms of both production and release, and that of PeCDF and TCDF in terms of environmental impacts. Lastly, through comparison with other developed countries and regions, it was concluded that room for further reduction exists, but can only be achieved through strengthened regulations and improved control measures.