Advances in air pollution control for key industries in China during the 13th five-year plan

Synergistic policy effects of digitization in reducing air pollution and addressing climate change in China

Given the increasing constraints of climate change and air pollution on economic growth, constructing a comprehensive policy system that promotes the coordinated development of pollution reduction, carbon mitigation, and economic growth has become the key to resolving current contradictions. However, the synergistic effects of the policy combination between digitalization, pollution reduction and carbon mitigation remain insufficiently evaluated. Based on panel data from 239 Chinese cities spanning 2014 to 2024, this study employs a fixed effects model to comprehensively analyze the effects of atmospheric, climate, and digital policy combinations from multiple perspectives. The results indicate that the synergistic effects of policy combinations surpass those of single policies. In the case of single policies, they demonstrate synergy while effectively achieving policy goals. Regarding policy interactions, the interplay between two policies entails both complementary and substitution effects. When considering policy combinations, an appropriate number of policies can maximize the overall policy effect, while excessive combinations may trigger substitution effects between policies. From the perspective of policy actors, collaborative efforts among policy actors strengthen the synergistic effects of policies, though an increasing number of policy actors does not necessarily enhance the synergy. This study provides theoretical references for designing collaborative policy mechanisms and establishing a collaborative development policy network system.

Selective leaching mechanisms of zinc from industrial waste using hybrid acids: Sustainable synthesis of Nano-ZnO

Zinc-containing dust (ZCD) has received extensive attention because it is a hazardous waste rich in various metals. This study innovatively proposed a hybrid acid leaching agent based on malic acid (MA) and sulfuric acid to selectively extract Zn from ZCD and successfully prepare nano-ZnO materials. The leaching experiments show that among the combinations of various organic acids and sulfuric acid, MA and sulfuric acid are superior in the selective leaching of Zn. Under optimal conditions, the leaching ratios of Zn, Pb, and Fe are 97.70%, 0.88%, and 2.95%, respectively. In addition, the use of hybrid acids can reduce sulfuric acid consumption by more than 46%. The Molecular dynamics simulation indicate that the interaction between the hybrid acid with ZnO and PbO was stronger (PbO > ZnO > Fe2O3). The radial distribution function (RDF) reveals that Zn and Pb ions form strong coordination structures with some oxygen atoms in MA, thereby confirming that MA plays a crucial role in preventing the dissolution of Fe. Finally, spherical nano-ZnO with a purity of 98.14% and an average particle size of 68.60 nm is obtained from the leaching solutions by precipitation method. This study provides a green and sustainable alternative for the selective recovery of Zn from ZCD.

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.