The atmospheric lead emission, deposition, and environmental inequality driven by interprovincial trade in China

Modifying national industrial structure for reducing heavy metals in China: A nexus-based multi-objective optimization approach

Heavy metals (HMs) exhibit significant toxicity and can lead to a range of health issues. Certain HMs share common emission sources, necessitating an exploration of the nexus among various HMs for achieving collaborative reductions. Considering the efficacy and feasibility of industrial modification to environmental pressures, this paper proposes a novel nexus-based optimization approach based on nexus analysis, multi-region input-output (MRIO) table, and multi-objective optimization to mitigate atmospheric HMs. The atmospheric HM emission inventory in 2017 is first compiled. Subsequently, the Integrated Nexus Strength of HMs Risk (HMR-INS) is proposed and employed to determine the range of sectoral output variations. Finally, a multi-objective optimization approach is employed based on the MRIO table in 2017. Compared with the traditional optimization method, the proposed approach performs better regarding HM-related risks and total output, leading to a 1.9 million tons increase in reduction on HM-related risks and a 1.37 trillion yuan increment in total output. Some further analyses are also given to provide feasible solutions for industrial modification, which considers both the economic efficiency and the stability of the industrial structure.

Revealing transmissions of atmospheric heavy metals hidden in the Chinese supply chain

Heavy metals (HMs) pose significant risks to human health and the environment. Identifying the sectors that play a significant role in the transmission of HMs has rarely been considered and represents an efficient method to control and manage HMs. By combining atmospheric HM emission inventories, the multi-regional input-output approach, and a betweenness-based method, this study revealed the transmission of HMs (comprehensively evaluated by the Heavy Metal Pollution Load, HMPL) in 2017. In 2017, 119.86 million tons of HMPL were transmitted through China's supply chain, and Cr was the main contributor to HMPL transmission. The results suggest that metal smelting is the primary contributor to HMPL transmission, and metal smelting in Jiangsu, Hebei, Henan, Shandong, and Anhui are the top five critical nodes. These results suggest that the sector's role changes dramatically with respect to HM control under this perspective. The role of HM emission-intensive sectors changed the most, as their production-based HMPLs accounted for 84% of the total HMPL; however, the HMPL transmitted by these sectors accounted for only 45% of the total. The critical HMPL transmission sectors identified in this study provide a basis for policy-making from a transmission perspective.

Deca-BDE emissions, validation, and environmental fate in China

Decabromodiphenyl ether (Deca-BDE) was officially listed in Annex A of the Stockholm Convention for persistent organic pollutants (POPs). It is necessary to establish its emission inventory to help reduce Deca-BDE contamination in the environment. We established a comprehensive Deca-BDE emission inventory in China. The results reveal that, from 2015 to 2017, the Deca-BDE emissions in its production source (source I) were less altered but increased annually in flame retarded plastics processing (source II), Deca-BDE-containing products usage (source III), and electronic waste (e-waste) treatment (source IV). We show that Deca-BDE emissions declined significantly in sources I and II but grew in source III and source IV from 2017 to 2018. We set up the provincial emission inventory to a gridded map on a spatial resolution of 0.25°× 0.25° latitude/longitude. The gridded inventory was incorporated into ChnMETOP model to simulate Deca-BDE concentrations in air and soil, and the modeled concentrations were compared to field-sampling data. The results show that the Deca-BDE emission inventory developed in this study agreed well with observed data, demonstrating that the Deca-BDE inventory in China developed in the present study is reliable. The inventory provides a support for quantifying human exposure risk to Deca-BDE and developing effective mitigation measures to mitigate Deca-BDE emissions.

Towards low-carbon domestic circulation: Insights from the spatiotemporal variations and socioeconomic determinants of emissions embedded within cross-province trade in China

For a country like China with unbalanced development pattern among provinces, domestic circulation (i.e., cross-province trade) is important for the long-term stability and prosperous development of economic market. However, with the rapid advance of integration of domestic regional economy, while expanding the internal market scale and deepening the provincial division of labor network for promoting the economic growth, the carbon emissions embedded within the cross-province traded products and services cannot be underestimated. Under the background of climate-trade dilemma, it is necessary to exploring the spatiotemporal variations and socioeconomic determinants of provincial "invisible" carbon emissions for a better understanding of trade-induced eco-environmental effects. To that end, this study developed an environmental-economic system model through integrating the environmentally extended multiregional input-output method and weighted average structural decomposition analysis technique to explore the trade-related emissions at the provincial level and generate the mitigation-management strategies for decisionmakers. Overall, more than half the emissions were embedded within cross-province goods and services trade over the whole study period. Furthermore, the distribution of traded emissions showed obvious spatial heterogeneity and great unbalance was existed between provincial imports and exports. Among all provinces, carbon surplus provinces were always more than deficit ones and the trading patterns of approximately 65% regions remained unchanged during 2007-2017. Remarkably, the emissions trading pattern undergone transition from carbon deficit to carbon surplus in provinces like Henan, Hubei, Guizhou, and so on. Conversely, provinces like Jilin, Shanghai, and Xinjiang showed opposite change. With the prevalence of online payment and electronic commerce in the future, the central and sub-national government could consider launching a pilot project for the design and creation of personal carbon consumption account in the carbon surplus provinces such as Guangdong, Henan, and Jiangsu. Meanwhile, for the provinces with larger carbon exports, it is necessary to establish the horizontal high technical transfer channels and vertical compensation mechanisms such as financial subsidies for improving the low-carbon production level. Our findings provided a holistic depict of national traded emissions at the provincial level, highlighting the importance of cross-province emission effect in exploring ways to promote the low-carbon transition of domestic circulation and fulfill the high-quality development of 'dual circulation' new pattern and successful achievement of 'double carbon' solemn commitment.