It is important to determine whether China's unprecedented expansion of college education (ECE) since 1999 has made a significant impact on the urban entrepreneurship and innovation (E&I). Using the data of 284 cities at the prefecture level and above from 2000 to 2020, this study empirically identifies the average treatment effect (ATE) of China's ECE on the urban E&I with its spatial spillover and explores two mediating channels (i.e., talent accumulation, and labor misallocation) to reveal how China's ECE impacts urban E&I. The results verify that with strong significance and robustness, the ECE for either undergraduates or master's students wholly matter for the E&I of cities, especially cities located in eastern or northeast economic zone，cities with a population less than 5 million or the ones without “Mass Innovation and Entrepreneurship Demonstration Bases”. Meanwhile, both the “Matthew effect” and the spatially “beggar-thy-neighbor” of ATE induced by the ECE are also be confirmed. Arguably, the China's ECE contributes either more talents accumulation or less labor misallocation, thereby furtherly boosting urban E&I. Above results were beneficial, especially at the decision-making for the developing countries to promote urban innovation and entrepreneurship under the scenario of college enrollment expansion.

As China’s economy transitions, environmental issues have become a major concern. This study examines the impact of Ambient Air Quality Standards (AAQS) on urban air quality using panel data from 284 cities in China from 2006 to 2019. The study utilizes DID (Difference-in-Difference) models to analyze the regulatory effects of AAQS and its spatial spillover. Additionally, the serial multiple mediation models are constructed to investigate the role of green innovation. The findings reveal that the AAQS positively affects urban air quality, albeit with a notable “hysteresis effect.” Local implementation of AAQS worsens air quality in neighboring cities within a distance of 400 km, but beyond 400 km, the effect is reversed. Heterogeneity analysis shows that AAQS improves air quality in central cities, large-sized and medium-sized cities, cities with weak environmental governance, and resource-based cities. Mechanism tests suggest that AAQS may enhance urban air quality by promoting green innovation and optimizing industrial structure. Especially, either the energy-use effect or industrial-structure effect triggered by green innovation can contribute to the improvement of urban air quality.

One of the Sustainable Development Goals is to enable cities to thrive, improve resource efficiency, and reduce pollution. However, balancing economic development with pollution control and fostering green growth remains a major challenge for developing countries. This study, using panel data from 284 prefecture-level and above cities in China from 2006 to 2020, evaluates urban green economy efficiency (GEE). Then, adopting implementation of “12th Five-Year Plan for Key Regional Air Pollution Prevention and Control” in China as a quasi-natural experiment, this study investigates the impact of air pollution prevention and control (APPC) on urban GEE. Findings reveal an overall upward trajectory in urban GEE across China, marked by discernible regional differentiations following implementation of national Plan. Considering the “hysteresis effect” and spatially “pollution halo effect”, APPC notably improves urban GEE, particularly within cities of eastern zone, high-population density cities, large-sized cities, non resource-based cities and major-APPC cities. Importantly, APPC acts as a catalyst for both enhancing green innovation quality and optimizing industrial structures, ultimately fostering urban GEE in China. These findings are significant and also provide a valuable supplement to the existing study.