It is of great significance to unveil the supply chain dynamics of the primary microplastic pollutants as well as to identify the emission responsibilities of different regions and sectors. In this study, a clustering-aided multiregional input–output microplastic emission (CMME) model is developed through integrating the multiregional input–output model and hierarchical clustering into a general framework. The CMME model can trace primary microplastic emissions under production-based accounting (PBA), consumption-based accounting (CBA), and income-based accounting (IBA). It can also reveal the emission patterns across regions and sectors, providing a practical basis for differentiating responsibilities and formulating policy implications. The results reveal that the microplastic emissions in the eastern coastal provinces of China are dominant; however, their contributions vary along with different perspectives (PBA: Guangdong > Shandong > Zhejiang; CBA: Guangdong > Zhejiang > Jiangsu; IBA: Shandong > Guangdong > Jiangsu). The results show that, under all perspectives, transportation and textile industries are the main contributors of microplastic emissions. Provinces with abundant energy resources (e.g., Inner Mongolia and Xinjiang) have a large number of energy extraction and processing industries, which form an important microplastic emission cluster under IBA. The findings are helpful in clarifying the emission responsibilities of different regions and industries, providing a scientific basis for the Chinese government to formulate policies for reducing and controlling microplastics emissions.
Wang et al. (Fri,) studied this question.