Based on the panel data of 224 prefecture-level and above cities in China from 2003 to 2016, this paper empirically studies the impact of urban sprawl on air pollution and introduces a mediating effect model to test the mediating role of vehicle ownership concerning the impact of urban sprawl on air pollution. The research in this paper arrives at three conclusions. First, urban sprawl has a significant positive effect on air pollution, and this conclusion is still valid after solving the endogeneity problem and conducting a robustness test. Second, the results of mediating effect test show that urban sprawl indirectly affects air pollution through the partial mediating effect of vehicle ownership. By removing the mediating effect, urban sprawl has a significant negative impact on air pollution, indicating that the mediating effect of vehicle ownership is higher concerning the impact of urban sprawl on air pollution. Third, further panel quantile regression results show that the higher the level of air pollution, the weaker the mediating effect of vehicle ownership and the stronger the direct effect of urban sprawl on air pollution. These conclusions can provide some empirical support for solving the air pollution problems caused by urban sprawl in China.

According to the new development pattern, implementing the development strategy driven by scientific and technological innovation (STI) is an important measure for each region to improve the quality of regional economic development. Exploring the effect of STI on the regional high-quality economic development (HED) is helpful to break the bottleneck and enhance the momentum of regional economic development. The Yangtze River Delta, located in the east coast of China, is the frontier of STI and economic development. Based on theoretical analysis, this paper uses the entropy method to calculate the STI index of the Yangtze River Delta from 2009 to 2018, and systematically investigates the impact of STI on HED in Yangtze River Delta by using two-way fixed effect, spatial Dubin model, panel threshold model and moderation effect model. The research finds that: First, under the control of other factors, STI has significantly promoted the HED of Yangtze River Delta region, while it also produces a spatial spillover effect. Second, the impact of STI on HED in the Yangtze River Delta has a double threshold effect based on the advanced industrial structure. Third, the analysis of adjustment mechanism shows that the scale of higher education has a positive adjustment effect in the relationship between STI and HED. Fourth, with the further analysis of regional heterogeneity, the economic effect of STI in central cities is significantly greater than that in noncentral cities. These findings provide theory-based direction and policy inspiration for improving the institutional mechanism of STI and accelerating the promotion of HED in Yangtze River Delta region.

In response to the severe situation of water and land resources in China, this paper uses the DPSIR (driving force–pressure–state–impact–response) model and two-stage network DEA (data envelopment analysis) model to evaluate the carrying capacity and utilization efficiency of land and water resources in 31 provinces of China from 2009 to 2017. The empirical results show that the carrying capacity and the efficiency values of land and water resources in most areas of China do not perform well and show a downward trend during the sample period. Specifically, the carrying capacity of land and water resources show a decreasing trend from north to south and from east to west. In addition, the response to the current situation of land and water resources has an important influence on the carrying capacity. The utilization efficiency of water and soil resources is significantly different in the two stages in most regions, indicating that the efficiency of economic benefit transformation is far greater than land and water resources development. Our results shed some insights on land and water utilization efficiency management and provide political recommendations for different regions.

Water and energy are critical resources for human well-being. The quantification and explanation of the water–energy nexus is important to enrich our understanding of sustainable utilization of water and energy resources in a unified framework. Herein, from the perspective of production efficiency, this study investigates the water–energy nexus in China’s industrial sector by developing a network data envelopment analysis (DEA) approach. Under two practical principles, we evaluate the water and energy usage efficiencies as well as give projection points in terms of industrial production and wastewater treatment processes for 30 provinces or urban areas in China during 2011–2015. The results show that the overall efficiency values of most provinces in the industrial water–energy nexus system are high although the efficiency value of each province fluctuates up and down in the sample period. When comparing two subsystems, for most provinces, the sub-efficiencies of the industrial production subsystem are relatively higher than those of the wastewater treatment subsystem under the economic priority principle or environment priority principle. Considering the projection points, the potential improvement space of the environment priority strategy is higher than that of the economic priority strategy. Based on the empirical results, relevant policy suggestions are provided to improve the provincial or urban industrial water–energy nexus system in reality.