The impact of smart city construction (SCC) on pollution emissions (PE): evidence from China

Based on panel data from 210 prefecture-level cities in China from 2003 to 2021, this study employs the Time-Varying Differences-in-Differences (Time-Varying DID) approach to systematically examine the impact of smart city construction on pollution emissions and its underlying mechanisms. Additionally, the Propensity Score Matching-Differences-in-Differences method is employed for further validation. The research findings indicate that Smart City Construction (SCC) significantly reduces urban Volume of Sewage Discharge (VSD), sulfur dioxide emissions (SO2), and Emissions of Fumes and Dust (EFD), thereby mitigating pollution emissions (PE) and enhancing environmental quality. Mechanism analysis reveals that SCC achieves these effects through scale effects, structural effects, and technological effects. City heterogeneity analysis shows that provincial capital cities exhibit a stronger suppression effect on pollution emissions compared to non-provincial capital cities. Moreover, cities with lower levels of education attainment demonstrate a stronger ability to curb pollution emissions, while larger cities exhibit a more pronounced impact on mitigating pollution emissions. The marginal contributions of this study mainly consist of three aspects: Firstly, it enriches the literature on environmental impact factors by assessing, for the first time, the influence of SCC on PE. Secondly, a comprehensive approach is employed, integrating VSD, EFD, SO2 data, and economic and pollution data at the city level. Time-Varying DID is used to evaluate the policy effects of SCC. Finally, the study analyzes the impact mechanisms of SCC policy on environmental emissions from various perspectives.

The synergistic reduction effect of PM2.5 and CO2: evidence from national key ecological functional areas in China

China faces the dual pressure of haze pollution control and carbon emission reduction. The goals of national key ecological functional areas (NKEFAs) are to improve ecological quality and enhance ecological supply. In this paper, a time-varying difference-in-differences model is used to assess the impact of NKEFAs on PM2.5 and CO2 by the panel data of prefecture-level cities of China and then investigate the synergistic reduction effect. This quasi-natural experiment reveals that NKEFAs can effectively reduce both PM2.5 and CO2 and then achieve the synergistic emission reduction effect. Land use pattern optimization and productivity enhancement are identified as key drivers for promoting this synergistic effect. This effect is observed in NKEFAs of water conservation and soil conservation types, as well as in the northern region, middle and lower reaches of the Yangtze River, and southeast coastal areas of the southern region. This study provides valuable theoretical references and empirical insights for realizing a synergistic status of environmental improvement and low-carbon transformation.

The impact of China's information infrastructure construction policy on green total factor productivity: moving towards a green world

China's economic growth over the past two decades has led to severe environmental pollution in most of its cities. To address this issue, China has developed and implemented several strategies to increase its resource utilization efficiency and move towards a green production economy, such as the information infrastructure construction policy (IICP). To assess the extent to which green production is being achieved, this study first measured the green total factor productivity (GTFP) in Chinese prefecture-level cities using a combined super slacks-based measure and the global Malmquist-Luenberger index (SBM-GML) model. Then, to assess the effectiveness of the IICP, the paths affecting the GTFP were explored using a time-varying difference-in-difference (time-varying DID) model. It was found that the IICP had significantly contributed to urban GTFP through its green technology diffusion effects and improved employment structures, with its implementation resulting in an average increase of 0.201 in the pilot cities compared to the non-pilot cities. This research attempted to explain how IICP plays a role in improving green production, and policy makers should attach importance to the power of IICP.

Green fiscal policy and enterprise green innovation: evidence from quasi-natural experiment of China

We aim to study the impact of green fiscal policy on enterprise green innovation by applying a time-varying difference-in-difference (DID) model, and treat the comprehensive demonstration city of fiscal policy for energy conservation and emission reduction (CPEE) in China as a quasi-natural experiment. The results show that the CPEE can significantly improve enterprise's green innovation performance of pilot area. This net policy effect is valid after a series of robustness tests to control for various potential confounding factors. Heterogeneity analysis reveals that the effect of CPEE is stronger for state-owned enterprises and enterprises in high energy consumption industries or industries with higher industrial concentration. In addition, the effect of CPEE is various among different categories of green patents, which is stronger for the types of alternative energy production category, waste management category, administrative supervision and design category. The mechanism test indicates that the CPEE can improve the green innovation performance by increasing enterprise' investment in research and development, promoting territorial industrial transformation and upgrading, and enhancing enterprise executives' environmental awareness. To achieve the carbon peaking and carbon neutrality goals, the green enabling role of fiscal reform pilot policy in transition economies and the applicability of localized policies should be excavated.

The impact of environmental supervision on firms' energy efficiency: evidence from the Environmental Protection Admonishing Talk policy in China

Enhancing energy efficiency is an important issue for countries facing pressures from energy shortages and environment pollution. Given increasing interest in the role of environmental supervision and the current lack of empirical evidence on this topic, this study investigates the impact of environmental supervision on firms' energy efficiency by taking the Environmental Protection Admonishing Talk (EPAT) policy in China as a quasi-natural experiment. Using the difference-in-differences method and the panel data of more than 3 million firms in China from 2008 to 2016, we find that environmental supervision improves firms' energy efficiency. This finding is validated by robustness tests and the difference-in-differences method combined with propensity score matching. The EPAT policy has varying effects on firms based on their location and size. A mechanism analysis shows that the EPAT policy improves firms' energy efficiency mainly by incentivizing them to adopt new technologies and transforming their modes of production. These findings can provide novel microscopic evidence on environmental supervision and energy efficiency and offer clues for the improvement of environmental enforcement in developing countries.

The impact of the establishment of carbon emission trade exchange on carbon emission efficiency

The China government focuses on changes in carbon emission efficiency with establishing carbon emission trade exchange (CETE). It is meaningful to study whether the pilot CETEs can facilitate the betterment of carbon emission efficiency. Using the data of 283 cities in China within 2006-2019, this article gauges the carbon emission efficiency with the SBM-DEA model. This paper analyzes the impact of China's pilot CETEs, which was gradually launched from 2013 to 2014, on carbon emission efficiency through the time-varying difference-in-difference (DID) model. Finally, the mediating effect model is further used to analyze the impact mechanism of the pilot CETEs on carbon emission efficiency from the perspectives of innovation investment and pollution control investment. The results reveal that the carbon emission efficiency of each city from 2006 to 2019 is not very ideal. All cities have some room to facilitate the carbon emission efficiency. The pilot CETEs have increased the carbon emission efficiency and reduced carbon dioxide emission. The policy influences the carbon emission efficiency through innovation investment and pollution control investment, which represent long-run and short-run mechanism respectively.

The emission reduction effect of daily penalty policy on firms

As one of the "four sharp teeth" of China's new environmental protection law, the daily penalty policy which is characterized by high deterrent effect and high violation cost plays an important role in restraining repeated violations of polluting firms. In order to further test the effectiveness of the daily penalty policy in pollution control and emission reduction, this study evaluates the policy through the time-varying difference-in-differences (DID) method using data from Chinese industrial firms from 2003 to 2012. The results show that the daily penalty policy significantly reduced industrial SO₂ emissions, which is supported by a series of robustness tests. Further mechanistic tests found that the daily penalty policy can reduce emissions by promoting the use of clean energy at the front-end prevention and increasing pollution control equipment and product innovation at end-governance. Heterogeneity analysis indicates that the daily penalty policy has a significant emission reduction effect on low energy consumption firms, large-scale firms and firms in clean industry. The SO₂ emission of foreign-funded firms is more reduced than that of state-owned and private firms. In addition, the level of emission reduction by exporting firms and firms in a mature recession are more affected by this policy. This study validates the effect of the daily penalty policy on emission reduction of firms. We found that the stringent command-and-control environmental regulations can also effectively encourage firms to control pollution and promote the transformation of firms toward long-term green development strategies and energy-saving and emission-reducing production patterns, and achieve a reasonable combination with market-based incentive environmental regulations. It provides new ideas and inspiration for implementation and improvement of the daily penalty policy and the strategic deployment of environmental governance in China.

Evaluating the effects of campaign-style environmental governance: evidence from Environmental Protection Interview in China

Campaign-style governance is one of the political methods adopted by the Communist Party of China and the Chinese government, which is usually used to make up for shortcomings when regular governance policies fail because the defined tasks are incompatible with other policy goals, especially in the field of environmental governance. An "Environmental Protection Interview (EPI)" is one of the campaign-style environmental governance methods that target local officials. In this paper, the causal relationship between the implementation of EPI and pollutant emission reduction was confirmed using the method of Time-Varying Difference-in-difference (Time-Varying DID) to compensate for endogeneity problem and ensure that the results are still valid after several robustness checks. Our regional heterogeneous analysis shows that the policy effects of EPI decrease from east to west in China and that they have different emission reduction effects on various types of pollutants. Unfortunately, the results also suggest that policy implementation only temporarily affects pollutant emission reduction, which could be attributed to the governance approaches of campaign-style enforcement according to the impact mechanism analysis. This paper implies that the EPI should be continued to be implemented in the future with some improvements on pollutant reduction mechanisms to ensure effective adoption.