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.

Assessing the role and driving mechanisms of the green financial reform on urban energy consumption and pollution emissions: a policy evaluation from the generalized synthetic control method

The Green Financial Reform and Innovation Pilot Areas (GFRIPA) policy is a key institutional arrangement that enables China's green finance to advance from theory to practice. Few studies have quantitatively evaluated the policy's environmental performance. This study uses a generalized synthetic control method (GSCM) alongside panel data from Chinese prefecture-level cities since 2007 to assess the effects of the GFRIPA policy on energy consumption and pollution emissions and to pinpoint the underlying mechanisms. Results show that establishing the GFRIPA significantly reduces energy consumption and pollution emissions, and that the effect emerges immediately in the policy's issuance year. Possible mechanisms consist of the increase in urban green innovation, the ease of financing constraints, the optimization of industrial structure, and the enhancement of environmental governance. Heterogeneity analyses reveal that policy effects are more profound in cities with a higher degree of marketization and a higher level of education. The findings provide valuable insights into consistently promoting the GFRIPA policy to meet environmental goals for energy conservation and pollution reduction and ultimately advance green economies in developing nations.

Does industrial symbiotic agglomeration reduce pollution emissions: evidence from eco-industrial demonstration parks in China

Industrial symbiotic agglomeration is important for promoting the circular economy and reducing pollution emissions. This paper examines the effects of industrial symbiotic agglomeration on pollution emissions using the staggered difference-in-difference model. The findings suggest the following: (1) industrial symbiotic agglomeration reduces total urban pollution emissions, with significant reductions in SO2 and wastewater, although not in solid waste and PM2.5 emissions. (2) The emission reduction effect is achieved mainly through green innovation, the recycling effect, and structural optimization, whereas the cost reduction effect of symbiotic agglomeration is not obvious. (3) Industrial symbiotic agglomeration promotes emission reduction in neighboring cities within a 300-km range, and this reduction decays with geographical distance. In addition, the pollution emission reduction effect of industrial symbiotic agglomeration is only realized when its size reaches 187.17 km2, with the effect becoming stronger as the size increases. At present, industrial symbiotic agglomeration mainly plays an emission reduction effect in non-resource cities. This paper provides a new way to promote the green development of industry and region.

Re-examining the governance effect of China's environmental protection tax

China has long exercised environmental control through the imposition of sewage charges. The start of the environmental protection tax on January 1, 2018, means that China has entered a new phase of environmental control. Unlike many previous studies on the role of environmental taxes at the firm level, this paper examines whether environmental taxes affect pollution emissions by influencing the behavioral choices of micro-actors. This paper first reviews the Pyrrhic tax, the Porter hypothesis, and the "double dividend effect." We then construct provincial panel data for 30 provinces in China from 2012 to 2019 as a sample, use the environmental protection tax as a natural experiment to evaluate the policy of this environmental protection tax using propensity score matching and difference-in-differences model, investigate the intermediate transmission mechanism of the policy implementation, and then analyze the differences in policy effects between provinces with different levels of economic development. The increased tax burden in 2018 led to a general reduction in provincial pollution emissions in which technological innovation by various groups, including firms and universities, had a mediating role.

The pollution reduction effect of official turnover: evidence from China

Under the political system with Chinese characteristics, the turnover of regional officials becomes a norm. So the uncertainty generated by the turnover of officials can often have an impact on the pollution emissions of regional enterprises. This paper examines the impact of official turnover on corporate pollution emissions using the Chinese industrial enterprise database and pollution emission database from 2004 to 2014 in China, while matching urban panel data of prefecture-level cities. The empirical study finds that official turnover significantly reduces the pollution emission of enterprises in that year, while the effect of official turnover from economically developed to economically backward regions and from economically backward to economically developed regions on enterprises' pollution emissions is significantly different. Also, this paper finds that the turnover of officials has a short-term effect on the reduction of corporate pollution emissions. The pollution abatement effect of official turnover is more pronounced in non-resource cities and non-state enterprises. Further analysis reveals that the pollution reduction effect of official turnover is more pronounced when the age of officials is greater than the promotion age threshold of 54 years. Finally, a series of robustness tests were conducted in this paper, while the Heckman two-step method was used to test for endogeneity, and the conclusions reached remained consistent with the benchmark regression.

Does China's low-carbon action reduce pollution emissions? A quasi-natural experiment based on the low-carbon city construction

To achieve the goal of "carbon peak and carbon neutrality", it is crucial for China to effectively control environmental pollution in low-carbon action (LCA). Based on the evidence from 283 cities in China from 2007 to 2019, the difference-in-differences (DID) method is applied to explore the impact of LCA on pollutant emissions represented by the pilot of low-carbon city construction (LCCC) in China. The main findings are as follows. First of all, the LCCC suppresses pollution emissions, and the basic conclusions are still stable after endogenous treatment and robustness testing. Secondly, the mechanism analysis reveals that the main path of LCCC affecting pollution reduction comes from the progress of green technology and the upgrading of industrial structure. Finally, the heterogeneity analysis shows that the pollution reduction effect of the LCCC is better in the eastern region and cities with higher level of green economy development. Based on the policy standpoint of environmental protection, the LCCC has opened up a reasonable exploration path for China and other countries in the world to carry out effective pollution reduction.

Spatial effect analysis of heterogeneous green technology innovations on pollution emission reduction: evidence from China's power industry

Based on the provincial panel dataset of the power industry in China from 1997 to 2020, this study employed the dynamic spatial Durbin model (SDM) to investigate the spatial effects of heterogeneous green technology innovations (GTIs) of the power industry chain-clean energy GTIs (GTI1), fossil-fueled GTIs (GTI2), energy-saving GTIs (GTI3), and power transmission technology innovations (GTI4)-on three pollution emission reduction: SO_2, solid waste (SW), and waste water (WW). The empirical results revealed that three pollution emissions showed "path dependent" and "snowball effects." GTI1, GTI2, and GTI3 reduced local SO₂ and SW emissions, while GTI2 and GTI4 had no obvious reduction effects on WW emissions. Different GTIs had the same spatial "symbiotic effects" on SO₂ emission reduction in the short term, showing positive spatial spillover reduction effects. Finally, it is of great significance to make full use of the positive spatial spillover effects of GTIs to promote the regional collaborative linkage of pollutant governance in the power industry.

Does environmental decentralization aggravate pollution emissions? Microscopic evidence from Chinese industrial enterprises

Rational division of environmental management power among governments is a necessary institutional support for speeding up the realization of green development goals. Based on the combined microdata of China Industrial Enterprise Database and China Enterprise Pollution Database from 2000 to 2012, the effect of environmental decentralization on enterprise pollution emission is empirically examined in this research. Results show that Chinese-style environmental decentralization, especially environmental supervision decentralization and environmental monitoring decentralization, significantly aggravates the pollution emissions of enterprises. Moreover, the impact of environmental decentralization on enterprise pollution emissions has regional and enterprise ownership heterogeneity. The mechanism test results denote that the production scale effect, energy structure effect and pollution control effect are the micro mechanisms of environmental decentralization aggravating the pollution emission of enterprises. This research confirms the existence of "race to the bottom" among local governments in China and provides evidence support and beneficial enlightenment for the vertical reform of the environmental management system.

Measurement of green total factor productivity on Chinese pig breeding: from the perspective of regional differences

China has a vast territory and abundant resources, and there are significant differences in the development of pig breeding in different regions. Chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) produced in the process of pig breeding will affect China's environmental quality. In view of this, based on the Minimum Distance to Weak efficient frontier model, this paper constructs Metafrontier-Malmquist-Luenberger (MML) index considering negative output under the common frontier to comprehensively evaluate the green total factor productivity of Chinese pig breeding (GTCP). This has guiding significance for improving China's pork production and reducing pollution emissions. The results manifest that (1) no matter under the common frontier or the group frontier, GTCP presents large temporal and spatial differentiation characteristics. Compared with the central region and the western region, the eastern region has obvious advantages in GTCP. (2) GTCP has shown an upward trend as a whole, which is mainly due to the technical progress. (3) Compared with small-scale and medium-sized GTCP, large-scale GTCP has apparent superiorities. Based on the above outcomes, this paper finally raises policy recommendations for improving GTCP: (1) give full play to the advantages of pig breeding in different regions, (2) increase the research and introduction of pig breeding clean technology and improve the application efficiency, and (3) give full play to the scale effect and vigorously develop large-scale pig breeding.

The impact of land resource mismatch and land marketization on pollution emissions of industrial enterprises in China

Local governments' strategy of increasing the land supply by selling industrial land at low prices causes industrial land in China to be priced substantially below the market value. Whether under planned or market allocation, urban land is an important part of China's market-oriented economic reform. However, direct empirical research on the impact of industrial land transfer on environmental pollution is still lacking. Based on matched data, this study investigates the impact of land resource mismatch and land marketization on the pollution emissions of Chinese enterprises. Pollution emissions refer to the emission intensity of industrial enterprises' major pollutants, such as industrial water, industrial waste gas and sulfur dioxide, and it is calculated by the comprehensive index method. The impact of land resource mismatch and land marketization on the pollution emissions of Chinese enterprises is investigated using a panel fixed effect model, subsample regression, the instrumental variable method and a mediating effect model. The benchmark analysis shows that land resource mismatch increases pollution emissions. The influence mechanism analysis shows that land resource mismatch may increase the pollution emissions of enterprises by causing overinvestment and low productivity. In addition, the expanded analysis shows that China's land marketization can reduce the intensity of and have a long-term impact on the pollution emissions of enterprises. This paper provides a theoretical and scientific basis for correcting the mismatch of land resources and promoting the reform of land marketization in China.

The state of science on severe air pollution episodes: Quantitative and qualitative analysis

Severe episodic air pollution blankets entire cities and regions and have a profound impact on humans and their activities. We compiled daily fine particle (PM_2.5) data from 100 cities in five continents, investigated the trends of number, frequency, and duration of pollution episodes, and compared these with the baseline trend in air pollution. We showed that the factors contributing to these events are complex; however, long-term measures to abate emissions from all anthropogenic sources at all times is also the most efficient way to reduce the occurrence of severe air pollution events. In the short term, accurate forecasting systems of such events based on the meteorological conditions favouring their occurrence, together with effective emergency mitigation of anthropogenic sources, may lessen their magnitude and/or duration. However, there is no clear way of preventing events caused by natural sources affected by climate change, such as wildfires and desert dust outbreaks.

Impact of the first induced COVID-19 lockdown on air quality in Israel

The coronavirus disease 2019 (COVID-19) induced a lockdown that has resulted in a sharp reduction in air and motor traffic and industrial activities. This in turn led to a reduction in air pollution around the world. It is important to quantify the extent of that reduction in order to estimate the weight of the impact of air and motor traffic and industrial activities over the total variation of air quality. An assessment of the extent of air pollution is aimed at facilitating the crafting of policies toward the reduction of pollution and the improvement in air quality. The aim of this paper is to evaluate the impact of the COVID-19 outbreak on air pollution in Israel. Particularly, we focus on Haifa and Greater Tel-Aviv (Gush-Dan), two regions with high air pollution, while examining different types of air monitoring stations. The period to which we refer to is March 8, 2020, to May 2, 2020. The results reveal two main findings: (1) During the COVID-19 lockdown, pollution emissions decreased relative to the same period in 2019. The biggest reduction was observed in NO _x , which, on average, was 41%. Surprisingly, ground-level ozone (O ₃) increased, and appeared to behave similarly to the ozone weekend effect. (2) The total percentage variation in pollution emission that was explained by the lockdown was at most 26%. By adding the meteorological conditions (which included measures of wind direction, wind speed, and temperature) as a factor in addition to the lockdown effect, this percent increased to 47%.

The impact of government-enterprise collusion on environmental pollution in China

Pollution emissions in China are associated with the relationship between local governments and enterprises, especially in those cities with government-enterprise collusion (GEC). We evaluate the causal relationships between GEC and SO₂ emissions at the enterprise level, by adopting the Propensity Score Matching-Difference in Difference method from a comprehensive environmental database. The empirical results show that, compared with those in the cities without collusion, SO₂ emissions of enterprises in the colluded cities increase by 11.3% (95% Confidence Interval (CI): 0.041-0.186). These GEC effects are more substantial in the cities whose regional officials work with longer terms, in the foreign-owned or small-scale enterprises, and the labour-intensive industries. The findings suggest the existing environment and personnel management policies in China should be adjusted for more sustainable development.

Global value chains, technological progress, and environmental pollution: Inequality towards developing countries

The production and trade activities of global value chains (GVC) increasingly contribute to the gross domestic product (GDP) of developing countries. However, while the development of domestic economies brings about technological progress, it also may have negative consequences such as environmental pollution. Technological progress can be conducive to reducing pollution emissions. Our motive is to realize the dual effects of technological progress and energy saving and emission reduction in developing countries' participation in the global value chain through research on GVC, technological progress and environmental pollution. Improving environmental quality through technological advances and reducing the adverse effects of inequality in trade status, enabling developing countries to obtain dividends from participating in the value chain as much as possible, and mitigating the adverse effects of environmental pollution during development. And lay the policy foundation for developing countries to go green. However, most of the current researches focus on the relationship between GVC and technological progress or GVC and environmental pollution, and the research on the relationship between the three is scarce. We use the WIOD database to try to find the relationship between developing country global value chain participation, technological progress and environmental pollution. Wang's method for GVC embedding is adopted for empirical research on input and output, energy utilization, high-skilled labor ratio, and pollution emissions in five typical developing countries, namely, Brazil, Russia, India, China, and Mexico. The relationships among the degree of participation in GVC, technological progress, and environmental pollution is studied from the perspective of industries in each country. The outcomes indicate that there is a value chain threshold in developing countries. When the degree of participation in a value chain is lower than the threshold, technological progress can result in an increase in pollution; otherwise, technological progress can reduce emissions. These results provide a theoretical basis and practical suggestions for developing countries to realize their own energy conservation, emission reductions, and green development while participating in globalized value chains. However, because the data related to the WIOD database is limited to 1995-2009, there are a few flaws in data integrity, which is also a challenge we face.