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Improving carbon emission efficiency is crucial for achieving carbon peak and carbon neutrality. This paper analyzes the carbon emission efficiency of Chinese cities using panel data from 275 prefecture-level cities between 2006 and 2020. The super-efficiency SBM (undesirable slacks-based measurement) model of undesired output, combined with kernel density estimation and exploratory data analysis, is employed. This study finds, firstly, from 2006 to 2020, the average efficiency of carbon emissions in Chinese cities declined from 0.53 to 0.48, indicating a downward trend. Secondly, from a temporal perspective, the level of dispersion in urban carbon emission efficiency has become increasingly distinct over time, coupled with a decrease in polarization. Thirdly, in terms of spatial analysis, urban carbon emission efficiency in China shows a positive correlation in a global context. In terms of local spatial correlation, it primarily exhibits high-high and low-low clusters, with a few instances of low–high and high-low clusters. Finally, based on the research findings, this paper proposes suggestions to improve urban carbon emission efficiency. [ABSTRACT FROM AUTHOR]

Green development is the main theme of modern development in China and even the world. Green development depends on green technology innovation (GTI). Therefore, for developing countries like China in the stage of economic transition, it is urgent to accelerate GTI to gain sustained advantages in the new round of international competition. As an important representative of contemporary rapid transportation, high-speed railway (HSR) can not only alleviate the rapidly growing transportation demand of the public, but also have potential benefits to the energy consumption structure and environmental quality. Whether and how HSR affects GTI has become the focus of this paper. Hence, by employing the panel data of 286 cities in China from 2007 to 2018 with the time-varying DID model, this paper verifies that HSR development can contribute to GTI. The main findings of this paper are as follows: (1) The operation of HSR can not only make the incremental development of GTI, but also improve the quality of GTI simultaneously. Moreover, the quality improvement effect of HSR is greater than the quantity increment effect. (2) Heterogeneity analysis shows that the positive effect of HSR on GTI is more significant for cities that have implemented LCCP. (3) This paper verifies the mediating effect of high-quality human capital. The opening of HSR further stimulates GTI by improving the level of high-quality human capital in cities and increasing the opportunities for knowledge exchange and diffusion. Based on the above findings, this paper proposes some policy recommendations to help developing countries achieve GTI with positive externalities. [ABSTRACT FROM AUTHOR]

In the process of global urban development, there are urgent ecological security and environmental pollution problems, green development is the fundamental way for urban sustainable development, economic transformation and mitigation of ecological and environmental problems. Based on the panel data of 283 cities at prefecture level and above in China from 2003 to 2017, this paper analyzes spatial–temporal evolution characteristics of urban green development efficiency (UGDE) and the peer effects of UGDE between cities of different grades. It is found that during the study period, in terms of temporal evolution, the average UGDE in China increased from 0.47 in 2003 to 0.61 in 2017, with a cumulative growth rate of 29.79%, showing a rising trend in general. In terms of spatial evolution, the number of low-efficiency cities and medium-efficiency cities continued to decrease. The eastern region has always been the main distribution area of higher-efficiency cities and high-efficiency cities; in the central region, UGDE in most cities improved significantly; in the western region, UGDE has always lagged behind that in the eastern and central regions. In addition, the center of gravity of UGDE presented a trend of northwest migration in general, with a total displacement of 100.07 km, and UGDE showed a spatial dispersion trend. The empirical results indicate that the improvement of UGDE in large cities has a driving effect on that in neighboring medium cities and small cities through the positive peer effect, and the growth of UGDE in medium cities has a promoting effect on that in neighboring small cities through the positive peer effect; the increase of UGDE in medium cities has a positive peer effect on that in neighboring large cities, and the growth of UGDE in small cities has a positive peer effect on that in neighboring medium cities; UGDE promotes each other between large cities through the positive peer effect. [ABSTRACT FROM AUTHOR]

Although the effect of highways on economic growth has been widely discussed, its role in green technological innovation has not yet attracted attention facing today's strong emphasis on the green economy. To fill this gap, this paper aims to provide empirical evidence by investigating the effects of highways on regional green technological innovation in China. The paper elaborates theoretically on three mechanisms through which the development of highways may influence regional green technological innovation, namely the agglomeration effect, spatial spillover effect, and network effect. To advance the empirical analysis, this paper constructs a spatial Durbin model accounting for spatial interdependencies among regions. Unlike previous literature, this paper uses "the strength of economic linkage" to indicate the development of highways in each city and discusses geographic distance and time-distance effect (spatio-temporal effect) resulting from highways. Using panel data of 105 prefecture-level cities in China's Yangtze River Economic Belt from 2001 to 2013, we find that: (1) highway has a significant role in promoting regional green technological innovation; (2) significant spatial spillover effects resulting from highways exist and the magnitude of the influence varies with geographical and temporal distance effect. Our findings provide references for developing transportation infrastructure and green innovation in China. [ABSTRACT FROM AUTHOR]

This paper investigates how National Eco-industrial Demonstration Parks (NEDP) in China affects carbon emission efficiency. The difference-in-differences (DID) strategy is used for analysis. This paper finds that the construction of NEDP is conducive to the improvement of carbon emission efficiency, and the findings remain robust through placebo tests and propensity score matching. Heterogeneity analysis shows NEDP construction has greater utility on carbon efficiency in non-resource-based cities as well as in environmentally friendly cities. The mechanism analysis found that green technology innovation, industrial restructuring, and the relocation of industrial enterprises are effective ways to improve carbon efficiency in NEDP. Finally, this paper finds that the construction of NEDP has obvious spatial spillover effects on carbon efficiency, which can effectively heighten the carbon efficiency level of this locality and nearby areas. [ABSTRACT FROM AUTHOR]

Green economy is the core content of the high-quality economic development, and the digital economy is the new driving force to accelerate the realization of high-quality economic development. In this regard, this paper selects 248 resource-based cities in China from 2011 to 2019 as the research objects and uses the fixed effect model and mediation effect model to test the relationship between digital economy and regional green total factor productivity. We get the following conclusions: First, there is the nonlinear relationship between digital economy and regional green total factor productivity, and this relationship shows the inverted U-shape. Secondly, digital economy can influence regional green total factor productivity through the path transmission mechanism of regional technological innovation, industrial structure, and environmental regulation. Finally, the effect of digital economy on regional green total factor productivity is heterogeneous, especially in the eastern region and cities with high human capital level. Based on the digital economy, the findings of this paper provide theoretical basis and reference suggestions for promoting the green development of regional economy. The government should attach importance to regional green development, actively guide the digital economy to promote green development, accelerate the development of the digital economy, and achieve high-quality economic development finally. [ABSTRACT FROM AUTHOR]

Food consumption has resulted in great carbon emissions in recent years. China has been facing the new mitigation challenge of carbon emissions with its emerging middle-income groups, especially in urban areas. This paper analyzes and predicts carbon emissions from food consumption (CEFC) of middle-income groups in the Yangtze River Economic Belt (YREB), which has a higher emerging middle-income group and the highest economic corridor in China. Few studies address CEFC analysis from middle-income groups perspective; thus, this paper calculates urban–rural CEFC of middle-income groups spanning 2010–2018 and predicts them in 2025, 2030 and 2035 using the extended IPAT model. Results are as follows: (1) YREB's urban–rural CEFC of middle-income groups show an upward trend and present a spatial pattern of "low–high–low–high" from the western region to the eastern region. Urban CEFC of middle-income groups are significantly higher than that of rural areas; (2) rural CEFC of middle-income groups in the YREB will first increase in 2025 and then decrease in 2030 and 2035. The growing trend of urban CEFC of middle-income groups will show a significant downward from 2025 to 2035. The growing proportion of urban CEFC of middle-income groups will exhibit an objective growth in 2035. Understanding the changing trend of CEFC of middle-income groups provides governments with differentiated and forward-looking suggestions toward coordinating middle-income groups' expansion and carbon emissions reduction. [ABSTRACT FROM AUTHOR]

This paper firstly uses the DEA-based Range Directional Model (RDM) and the Global Malmquist–Luenberger (GML) index to calculate the Green Efficiency Index (GEI) of China's cities under the constraints of pollution emissions, energy consumption, and natural resource occupancy. The GEI shows that the average green efficiency of the 285 sample cities achieved a total improvement of 10.1% from 2003 to 2019. The average cumulative improvement rate of green efficiency in the 110 cities in Pollutants Emission Trading Pilot Scheme (PETPS) from 2003 to 2019 was 14.9%, which was higher than the average of non-pilot cities (8.6%). Subsequently, this paper constructs a spatial difference-in-differences model (Spatial-DID) to empirically test the green efficiency promotion effect of PETPS from two aspects: local and spatial spillover. It is found that PETPS can promote the progress of local green efficiency in pilot cities, but there is a spatial spillover effect that is not conducive to the green efficiency progress in surrounding areas. The results of the mediation effect analysis show that the launch of PETPS will significantly reduce the clustering of industrial production activities in the pilot cities, thereby accelerating the green efficiency progress. However, PETPS can also promote clustering of industrial production activities in surrounding areas, thereby inhibiting the green efficiency progress in surrounding areas. These analysis results can fully explain the cause of the negative spatial spillover effect of PETPS. [ABSTRACT FROM AUTHOR]

Since the reform and opening up, China has achieved rapid economic development at the cost of environmental pollution, but this extensive development mode is increasingly difficult to sustain. Fortunately, China has begun to attach importance to environmental pollution and green output, and the central and local governments have successively issued many environmental regulation policies. Taking 285 prefecture-level cities in China from 2003 to 2017 as samples, this paper uses slacks-based measure (SBM) model based on unexpected output to measure the green output efficiency. Taking green output efficiency as the explanatory variable and environmental regulation as the explanatory variable, this paper analyzes its local effect and neighboring effect. The regression results of the whole sample show that environmental regulation in China will have a positive impact on green output efficiency, but it will have a negative impact on neighboring cities. Furthermore, considering the differences of economic development levels among the eastern, central and western regions of China, the samples of the three regions were regressed, and it was found that the higher the economic development level, the greater the impact of environmental regulation on the regions. Therefore, cities should not only ensure their own characteristics, but also pay attention to policy coordination among cities when formulating relevant environmental regulation policies. [ABSTRACT FROM AUTHOR]

While the cancellation of highway tolls can reduce costs and increase efficiency in the transportation industry, it also triggers environmental problems. Using panel data on 276 cities in China from 2005 to 2019, we explore the urban haze pollution and its mechanism caused by cancellation of high-grade highway tolls with a combination of propensity score matching and time-varying difference in differences, and also apply a spatial Durbin model to test the haze pollution spatial spillover effect. The study shows that the cancellation of high-grade highway tolls significantly aggravates haze pollution in cities. Regional heterogeneity analysis indicates that the policy has a greater impact on eastern cities and raises haze pollutions in resource-based cities more than in non-resource-based cities. Further mechanism tests show that the policy exacerbates urban haze pollution through the detour effect and pollution spatial spillover effect. The findings of this paper enrich the literature on the environmental impacts of highway toll behavior and provide experiences for the formulation and implementation of highway toll policies in China's transportation sector. [ABSTRACT FROM AUTHOR]

Improving total factor carbon emission efficiency (TCE) is the key to achieving carbon emission reduction targets while ensuring economic growth. In this paper, the global Malmquist index based on the SBM model is used to measure TCE of 283 cities in China from 2011 to 2019. On this basis, this paper uses the spatial econometric model and intermediary effect model to empirically analyze the impact of industrial co-agglomeration on TCE and its transmission mechanism. Furthermore, considering the differences in geographical location and resource endowment among regions, this paper analyzes the heterogeneous effect of industrial collaboration agglomeration on TCE in different regions and cities. The results show that: (1) Industrial co-agglomeration can improve TCE, and its main transmission channel is technological innovation. (2) Industrial co-agglomeration has a positive spatial spillover effect. Industrial co-agglomeration in one region can improve the TCE in the surrounding regions. (3) Industrial co-agglomeration of cities with different geographic locations and resource endowments has a heterogeneous effect on TCE. Regarding geographical heterogeneity, the industrial co-agglomeration in the eastern region has the greatest promoting effect on TCE, followed by the central region. However, the impact of industrial co-agglomeration in the western region on TCE is not significant. Regarding resource endowment heterogeneity, the industrial co-agglomeration in non-resource-based cities has a greater promoting effect on TCE than that in resource-based cities. [ABSTRACT FROM AUTHOR]

Under the background of digitization and greening in China, digital infrastructure offers new opportunities for developing green innovation. This paper investigates the effect of digital infrastructure on urban green innovation using panel data from 285 Chinese prefecture-level cities between 2011 and 2020, and explains the mechanism and its spatial-temporal dynamic effect. The results demonstrate that digital infrastructure promotes urban green innovation. Talent agglomeration, R&D investment increase, and industrial structure upgrading are crucial channels. Furthermore, depending on a city's size, human capital, environmental regulations, and financial subsidies, digital infrastructure contributes to urban green innovation differently. Also, there is not only a positive spatial spillover effect of digital infrastructure but a threshold effect that presents a nonlinear trend of rising marginal effect. This study provides a new perspective for promoting digital infrastructure and urban green innovation, which makes a difference in facilitating its high-level development collaboratively. [ABSTRACT FROM AUTHOR]

This paper explores the impact of population agglomeration on urban economic development quality in various cities of China. The results show that population agglomeration significantly contributes to the improvement of urban green total factor productivity by increasing population diversification, promoting knowledge spillovers, and reducing pollution emission intensity. Moreover, we find that population agglomeration in type II big cities and type I large cities significantly improves green total factor productivity, while the impact of population agglomeration in metropolises and mega-cities on green total factor productivity is not significant. On the one hand, type II big cities and type I large cities are in the period of rising economic development, the population has not yet reached saturation, and there is still a large demographic dividend space. On the other hand, excessive population agglomeration also brings about "urban diseases" such as population congestion and traffic congestion, especially in the metropolises and mega-cities. Finally, using data on producer services and its sub-sectors, we identify a more significant driving effect of high-end talent agglomeration on green total factor productivity. [ABSTRACT FROM AUTHOR]

The issues of housing and traffic in China's mega cities have become increasingly pressing problems, particularly for middle/low-income tenant workers. These tenants are from less advantaged socioeconomic backgrounds, which has resulted in a significant geographical separation between their workplace and their residence. Although a large number of studies have confirmed that built environment factors have a solid impact on residents' commuting distance, few studies have investigated the mechanism underlying the nonlinear influence on middle/low-income tenants. This paper aims to provide an in-depth analysis of the key factors and nonlinear influencing mechanism of the built environment on middle/low-income tenant workers' commuting distance by establishing a gradient-boosting decision tree model, using Beijing as an empirical case. The paper reveals three primary findings: (1) An important nonlinear relationship between the surrounding built environment and peoples' jobs–housing spatial proximity can be observed for those middle/low-income tenant workers who use slow and public modes of commuting. Specifically, the density of public transport stations, road networks, and workplaces, and the land use mix play a dominant role. (2) A limited effect of built environment factors can be found for the same group of tenant workers who choose cars as their mode of commuting. (3) The differences in self-selected commuting modes have a significant mediating effect on the relationship between the built environment and jobs–housing situation among middle/low-income tenant workers. Given this, effective policy guidance for residents' travel modes is necessary to optimize the built environment indicators to achieve the best effect. In addition, we should consider giving priority to the matching indicators such as land use mix and resident population density. Another possibility is to strengthen the connection to the public transport stations, which in turn can optimize the walkability in residential environments. [ABSTRACT FROM AUTHOR]

The intelligent city pilot policy is a major measure in China to promote urban development from factor driven and investment driven to innovation driven. Intelligent city construction can effectively coordinate specialized production factors and information sharing mechanism, promote digital information technology innovation, promote smart industry cluster, and expand ecological scenarios of clean industry application, so as to reduce carbon emissions. This paper reveals the internal mechanism of intelligent city construction to promote carbon emission reduction. Based on the quasi-natural experiments carried out in three batches of pilot construction of intelligent cities since 2012, the difference-in-difference model (DID) is used to identify its impact on urban carbon emissions. The research results show that the pilot construction of intelligent cities is conducive to reducing carbon emissions, which is still robust under multiple scenarios such as placebo test and endogenous test. Heterogeneity analysis shows that the pilot policies have a more significant carbon emission reduction effect on the Beijing-Tianjin-Hebei urban agglomeration, non-resource-based cities, and non-old industrial bases. After further quantitative analysis of 917 pilot policy texts based on Simhash algorithm, Jieba word segmentation, and word frequency statistics, it is found that intelligent industry policies reduce carbon emissions by driving data elements agglomeration and optimizing industrial structure, while intelligent government and intelligent people's livelihood policies improve energy efficiency and reduce carbon emissions through green technological innovation. Counterfactual tests using machine learning algorithms show that the later the pilot batch, the better the sustainable carbon emission reduction effect of intelligent city pilot policies. [ABSTRACT FROM AUTHOR]

Whether the technological finance cooperation pilot (TFCP) policy in China can promote energy efficiency remains under investigated. Using the dataset covering 284 cities in China from 2003 to 2019, this paper adopts the Super-SBM model with undesirable outputs to measure energy efficiency. Based on this efficiency, the Difference-in-Differences model (DID) and Spatial Durbin model (SDM) are employed to discuss the impact of TFCP policy on energy efficiency. Results demonstrate that TFCP policy has significantly promoted energy efficiency. And the conclusion is still valid after the robustness checks and endogenous treatment has been carried out. The impact of the TFCP policy on energy efficiency is heterogeneous, depending on the geographical, administrative, and resource characteristics of cities. To be specific, the promotion effect tends to be pronounced in east-central cities, high-ranking cities, and high-tech cities. Moreover, TFCP policy could significantly improve energy efficiency through the effects of technological innovation, industrial upgrading, and financial development. A further policy spillover analysis shows that TFCP policy has exerted a remarkable incentive influence on energy efficiency locally, while the neighboring cities are inhibitive. To sum up, this research is of important theoretical value and policy-making reference on green economy transformation for cities with differential features and energy utilization capacity, by shedding light on the impacts of such a technological finance cooperation system on energy efficiency. [ABSTRACT FROM AUTHOR]

This paper investigates how digital finance alleviates the resource curse effect from resource-based cities in China. This paper selects the data from 88 resource-based cities in China from 2011 to 2019 to construct the econometric model test hypothesis. The results show that (1) a resource curse does exist in Chinese resource-based cities. (2) Digital finance can alleviate the resource curse of resource-based cities in China, and this effect has two significant thresholds. (3) The heterogeneity test results show that digital finance's mitigation effect on the resource curse significantly differs in cities with different environmental regulation intensities and resource abundance. (4) Using the implementation of the broadband China strategy as the proxy variable of digital finance for the robustness test, the above conclusions are still robust. This paper considers the impact of digital upgrading on the financial industry and further studies the mitigation effect of digital finance on the resource curse. It provides a new perspective to study the recent changes in traditional issues in the digital era. [ABSTRACT FROM AUTHOR]

In this paper, the adoption of SO2 emission tax rates higher than the legal minimum standard is regarded as a noteworthy policy reform in China (quasi-natural experiment), and a spatial Difference-in-Differences (Spatial-DID) model is constructed to test the direct effects (local effects) and indirect effects (spatial spillover effects) of SO2 emission tax policy reform on PM2.5 concentrations in the atmosphere of 285 China's cities. The estimation and calculation results of the Spatial-DID model show that the SO2 emission tax policy reform can significantly reduce local PM2.5 concentration and significantly promote PM2.5 concentration in surrounding areas. The results of heterogeneity analysis show that the SO2 emission tax policy reform can produce a relatively more beneficial spatial spillover effect in eastern cities and higher administrative level cities, while the pollutants emission rights trading and the reform of NOx emission tax rates can produce beneficial spatial spillover effects when cooperating with the reform of SO2 emission tax rates. The results of the mediation effect analysis show that the higher SO2 emission tax rate can aggravate the surrounding PM2.5 pollution by promoting the aggregation level of industrial production factors and the industrial SO2 emission intensity in the surrounding areas, which can support the existence of the pollution heaven effect. [ABSTRACT FROM AUTHOR]

The economic and technological development zone (ETDZ) serves an essential role in driving green development and ecological civilization. Therefore, it is crucial to investigate the impact of ETDZs on eco-efficiency for sustainable development. This paper investigates the impact of the establishment of ETDZs on eco-efficiency by constructing a differences-in-differences (DID) model on the basis of 253 cities in China from 2004 to 2017 as the dataset. This paper also explores the possible intrinsic impact mechanisms through the channels of industrial structure and technological innovation by constructing a mediating effect model, and the heterogeneous effects of ETDZs on eco-efficiency from the perspectives of regional imbalance and city class heterogeneity. Statistical results report that ETDZs significantly positively affect eco-efficiency and such effects are most significant in the first year after the establishment of ETDZs. Industrial structure upgrading and technological innovation are essential role mechanisms for ETDZs to enhance eco-efficiency. Besides, the enhancement effect of ETDZs on eco-efficiency is only observed in the eastern part of the city, with an insignificant inhibitory effect in central and western parts of the cities. However, the establishment of ETDZs in cities with higher city classes is more beneficial to improve eco-efficiency. [ABSTRACT FROM AUTHOR]

Resource-based cities, which are widely distributed in China, contribute significantly to China's sustainable development. The digital economy and the construction of ecological civilization are central issues in the sustainable development of resource-based cities, and it is necessary to analyze the impact of the digital economy on the ecological resilience of resource-based cities. Thus, this paper measures ecological resilience of 117 resource-based cities from 2011 to 2020 using the entropy weight TOPSIS (technique for order preference by similarity to ideal solution; see Table 1 for a list of acronyms) method and empirically investigates the impact and mechanism of digital economy on ecological resilience using the spatial Durbin model (SDM) and intermediary effect model. The results show that the ecological resilience of resource-based cities has a certain upward trend, with a stepwise distribution pattern from east to west. There is a significant positive correlation between ecological resilience of resource-based cities, showing the phenomenon of club convergence which is primarily dominated by high-high (H–H) and low-low (L-L). The digital economy has a significant spatial spillover effect, which promotes ecological resilience of resource-based cities in the local and adjacent regions. A mechanism analysis reveals that technological innovation and industrial structure are mediators between digital economy and ecological resilience of resource-based cities, with significant heterogeneity in region and growth cycle. Among them, the intermediary role of technological innovation is stronger. Following the above findings, this paper proposes policy suggestions related to digital economy evolution and ecological resilience enhancement. This paper further enriches the literature on the ecological resilience and provides a theoretical basis for government policy-making. [ABSTRACT FROM AUTHOR]

There are urgent ecological and environmental problems in the process of the utilization of urban construction land, promoting green utilization of construction land is conducive to urban sustainable development and high-quality economic development. Based on the panel data of 108 prefecture-level and above cities in the Yangtze River Economic Belt, China from 2003 to 2017, this paper uses the super-efficiency SBM model to measure the green efficiency of urban construction land (GEUCL), analyzes its spatial–temporal evolution characteristics, and constructs the spatial autoregressive model to study its spatial spillover effects from the perspective of urban hierarchy. It is found that, in terms of temporal variation, the average efficiency value shows a fluctuating upward trend during the study period, rising from 0.27 in 2003 to 0.39 in 2017, the cumulative growth rate is 44.44%, with an average annual growth rate of 3.14%. In terms of spatial distribution characteristics, during the study period, the number of medium-efficiency and high-efficiency cities increases significantly, while the number of low-efficiency cities decreases sharply; high-efficiency cities always present scattered distribution, while medium-efficiency cities change from scattered distribution to agglomeration distribution. In addition, GEUCL has significantly positive spatial spillover effects between neighboring cities of different grades and between neighboring cities of the same grade, among them, the increase of GEUCL in higher-grade cities has significantly positive spatial spillover effects on that in adjacent lower-grade cities; the increase of GEUCL in lower-grade cities has significantly positive spatial spillover effects on that in neighboring higher-grade cities; GEUCL has significantly positive spatial spillover effects between neighboring cities of the same grade. [ABSTRACT FROM AUTHOR]

Cities are the main spaces to study a low-carbon economy. This paper introduces basic concepts covering "tolerance of planning carbon emissions," "inevitable carbon emissions" and "excessive carbon emissions," then discusses the problem with optimal city carbon emissions under the condition of tolerance. Theoretical analysis and scenario analysis were employed. First, according to optimal allocation theory of resources, we discuss how optimal society carbon emissions take place. Then, the deviation of optimal city carbon emissions was explored and analyzed, which was mostly caused by the missing price of carbon emissions allowance, excessive carbon emissions, and so on. Third, we analyzed optimal city carbon emissions under different conditions, in which different types of tolerance were included. Results show that theoretical investigations on optimal city carbon emissions provide relative ideas for determining control index and optimizing control countermeasures. Policy implications include improving the control index of city carbon emissions through environment enhancement, setting a reasonable control index of city carbon emissions under the consideration of the relationship between city economy and its environment, and establishing trading allowance and compensation mechanism of city carbon emissions, etc. [ABSTRACT FROM AUTHOR]

The haven paradise hypothesis has been widely supported in the international carbon transfer, but there is still a lack of inter-city evidence. The emergence of the digital economy in recent years has introduced unprecedented opportunities and challenges for carbon emissions reduction and carbon transfer. As the world's largest carbon emitter and a major player in the digital economy, exploring whether the pollution haven hypothesis exists among cities in China and how the digital economy affects inter-city carbon transfer is crucial for countries to optimize their domestic carbon reduction structures. To this end, this paper employs the 2012 and 2015 Chinese Urban Household Survey data alongside input-output tables based on the life cycle assessment method to quantify the inter-city carbon transfer. In addition, the impact and mechanisms of the digital economy on inter-city carbon transfer are explored using the two-way fixed effects model. The results show that 54% of Chinese cities' carbon emissions come from outside, with third-tier cities bearing high carbon transfer pressures, indicating the presence of the pollution haven hypothesis. The digital economy exacerbates inter-city carbon transfer by promoting market integration and facilitating industrial transfer, and it mainly promotes the transfer of high-intensity carbon emissions to third-tier cities. Considering carbon emission reduction targets, mandatory environmental regulations have strengthened the effect of the digital economy on carbon transfer. Therefore, the Chinese government needs to properly address carbon transfer by improving the collaborative carbon reduction system, enhancing carbon emission reduction efficiency, and accelerating the equitable progress of the digital economy. [ABSTRACT FROM AUTHOR]

As cities suffer from frequent pollution events and massive population gathering in cities, haze pollution and human capital exert a significant influence on economic resilience. Thus it is significant to thoroughly investigate city economic resilience for the sound development of the city economy and enhance economic resilience. Based on the data from 239 cities in China from 2005 to 2017, this paper uses the OLS model to study the impact of haze on economic resilience. The findings reveal that haze pollution significantly reduces economic resilience. Also, there is a significant negative correlation between haze pollution and economic resilience in the East and Middle areas, while there is an adverse nexus in the West. Human capital has a positive role in promoting economic resilience, and this role is the strongest in the Middle area and the weakest in the West area. Moreover, human capital positively moderates haze pollution and economic resilience in Full sample, and East and Middle sample sets, while insignificant in the West sample set. Considering the possible endogeneity of the model, the robustness of the above results is tested using System GMM two-step and 2SLS methods. From the perspective of haze pollution, this study deeply excavates the short board factors affecting economic resilience. It regards human capital as an essential variable to repair the weak links of the economy and enhance economic resilience, which is conducive to improving the anti-risk ability of China's economy under the background of the gradual intensification of the contradiction between environmental pollution and economic growth. [ABSTRACT FROM AUTHOR]

This paper uses Baidu migration data to obtain the intercity trips between cities in China. Taking intercity travel as a functional connection between cities, taking into account the internal and external intercity travel connections of urban agglomerations, an improved rank scale distribution method was used to quantitatively measure the form and function of the Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta, middle reaches of the Yangtze River, Chengdu-Chongqing, Central Plains, Guanzhong, and Harbin-Changchun urban agglomerations. It is found that, firstly, there are differences in the Functional Polycentricity presented by the internal and external connections of urban agglomerations, which are related to the economic development of urban agglomerations and central cities. Secondly, there are differences between Morphological Polycentricity and Functional Polycentricity of the eight urban agglomerations measured by the internal and external connections, indicating that the external connections have a significant impact. The internal and external connections of urban agglomerations are important functional connections of urban agglomerations. The study of urban agglomerations should not ignore the internal or external connections, and the overall consideration can more comprehensively reflect the polycentric characteristics of urban agglomerations. The internal and external connections of urban agglomerations are important functional connections, and the study of urban agglomerations should not ignore internal or external connections. Overall consideration can better reflect the polycentirccharacteristics of urban agglomerations. [ABSTRACT FROM AUTHOR]

This paper empirically examines the specific impact effects and mediates transmission mechanisms of rising housing prices on urban green development using the data from 285 prefecture-level cities in China from 2010 to 2019. The results show that: 1. the rapid rise in housing prices significantly inhibits the improvement of urban green total factor productivity (GTFP) and is not conducive to promoting urban green development; 2. the effect of high housing prices on the GTFP of cities with different population size, geographical location, and resource mastery shows a significant heterogeneous effect; 3. The study of the transmission mechanism finds that soaring urban housing prices not only lead to investment distortions that weaken the overall research and innovation capacity, but also have a "solidifying lock-in" effect on the industrial structure of cities, which in turn creates obstacles to the enhancement of urban green efficiency. [ABSTRACT FROM AUTHOR]

Public investments in subway systems are often motivated by improving local air quality. Recent studies, however, have reached different conclusions on the air quality benefits of subway investment. To reconcile these findings, this paper examines the air quality effects of all 359 subway line openings in China between 2013 and 2018. The machine learning method adopted in this paper substantially improves the consistency and precision of the estimates by purging seasonality, volatility, and the nonlinear effects of meteorological conditions in air quality data. The empirical results suggest an insignificant short-term effect and a significant long-term effect, which is expected as the adjustment of commuting mode takes time. Using the causal forest approach, the heterogeneity analysis find that a city that is experiencing rapid economic growth from a lower income level and currently has fewer subway lines is more likely to experience statistically significant improvements in air quality from a subway opening. These findings help reconcile the different findings in the literature and shed light on air pollution reduction as one of the objectives of public transit investment. [ABSTRACT FROM AUTHOR]

This paper examines the impacts of local housing sentiments on the housing price dynamics of China. With a massive second-hand transaction dataset, we construct monthly local housing sentiment indices for 18 major cities in China from January 2016 to October 2020. We create three sentiment proxies representing the local housing market liquidity and speculative behaviors from the transaction dataset and then use partial least squares (PLS) to extract a recursive look-ahead-bias-free local housing sentiment index for each city considered. The local housing sentiments are shown to have robust predictive powers for future housing returns with a salient short-run underreaction and long-run overreaction pattern. Further analysis shows that local housing sentiment impacts are asymmetric, and housing returns in cities with relatively inelastic housing supply are more sensitive to local housing sentiments. We also document a significant feedback effect between housing returns and market sentiments, indicating the existence of a pricing-sentiment spiral which could potentially enhance the ongoing market fever of Chinese housing markets. The main estimation results are robust to alternative sentiment extraction methods and alternative sentiment proxies, and consistent for the sample period before COVID-19. [ABSTRACT FROM AUTHOR]

The optimization and transition of the industrial structure help improve the quality of the economy, moving it toward low-carbon development. By using the Instrumental Variable Generalized Method of Moments model and a city-level dataset covering the period 2006–2019, this paper explores the carbon lock-in mitigation effects of industrial structure optimization and industrial structure transition, respectively. The heterogeneity and the synthetic industrial structure adjustment effect are detected, and the potential impact mechanism is also explored. Some findings have been generated. (1) Both industrial structure optimization and industrial structure transition realize carbon lock-in eradication. (2) Industrial structure optimization and transition are more effective in inhibiting carbon lock-in in cities with a higher level of economic background. (3) By generating an interaction term of industrial structure optimization and transition and examining the impact of the interaction term on carbon lock-in, this paper detects that industrial structure optimization and transition have a synthetic impact on carbon lock-in, showing a "1 + 1 > 2" effect. (4) Industrial structure optimization and transition both affect carbon lock-in by improving technological innovation level, which is the impact mechanism. Some policy implications, such as sectoral diversification and promoting research and development, are put forward for better industrial structure development and carbon unlocking. [ABSTRACT FROM AUTHOR]

Evaluating the effects of China's carbon emission trading scheme (ETS) is crucial for the coordinated development of Chinese cities. Therefore, based on the panel data of 242 cities in China from 2008 to 2019, this paper uses the multi-period difference-in-difference (DID) model to comprehensively evaluate the impact of carbon market on the coordinated development of cities from the perspectives of carbon market policy and carbon market efficiency, and then analyzes the mechanism and heterogeneity of the effect of carbon market efficiency. The results show that both carbon market policy and carbon market efficiency can promote the coordinated development of cities. Science and education expenditure plays a significant intermediary role in the impact of carbon market efficiency on the coordinated development of cities. The heterogeneity test finds that the stricter the performance penalty system, the higher the level of urban coordinated development, and the stronger the effect of carbon market efficiency. The findings of this paper provide policy recommendations for further improving the construction of China's pilot and national ETS and enhancing the coordinated development of Chinese cities. [ABSTRACT FROM AUTHOR]

Travel has become the most popular way to relieve stress at present. Choosing suitable travel cities and scenic spots among the many alternatives and planning travel routes are the two most troublesome problems for people. For the first question, this paper uses the multi-criteria decision-making method—best-worst method (BWM) to build a priority model of core scenic spots to help people filter out the cities and core scenic spots with the highest travel value from a large number of tourist attractions. For the second question, this paper uses the genetic algorithm to plan the travel route of core scenic spots, so as to reduce the cost of tourists in the travel process and improve the travel happiness as much as possible. Subsequently, a case about the selection of core scenic spots and travel route planning in Hubei Province of China was presented. Among them, 6 cities (i.e. 24 core scenic spots) with the highest travel priority were selected by the score of BWM. Then, the genetic algorithm was programmed by MATLAB to obtain the optimal travel routes of these 24 core scenic spots, with a total distance of 1355.72 km. This paper will promote the practical application of BWM and genetic algorithm. Highlights: Best-worst method (BWM) is applied to filter out the cities and core scenic spots with leading travel values. Genetic algorithm is utilized to plan the travel route of core scenic spots. Case study on Hubei Province of China is conducted to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper uses the spatial panel data model of 272 cities in China from 2000 to 2010 to explore the relationship between ecological infrastructure and tourism development to determine the influencing degree of ecological infrastructure on tourism development. It is found that the expansion of ecological infrastructure has promoted tourism development, with different regional performances. For subsamples with different environmental governance capacities, the expansion of ecological infrastructure generates greater and more tourism growth only for cities with the best ecological infrastructure (BEI cities). In exploring the potential mechanism, BEI cities have the strongest environmental governance effect, followed by cities with good ecological infrastructure (GEI cities) and cities with normal ecological infrastructure (NEI cities), while negative environmental governance effect exists in cities with poor ecological infrastructure (PEI cities). Environmental governance capacity is critical for promoting tourism growth. On spatial correlation, NEI and PEI cities compete for tourism development, but promote each other in BEI and GEI cities, while both ecological infrastructure and environmental governance capacity have a neighbor–companion relationship. The contributions of this paper are: (1) Cities with different types have heterogeneous characteristics. (2) The mechanism linking ecological infrastructure and tourism development is environmental governance effect, with different effects in different types of cities. (3) Spatial interaction among cities is fully considered. [ABSTRACT FROM AUTHOR]

Although green technology innovation is an important means to balance the environment and economy, few studies have analyzed the employment effects of green technology innovation in developing countries. Therefore, this paper employs the panel data of 286 prefecture-level cities in China from 2006 to 2017 to empirically test the impact of various green technology innovations on urban employment. Meanwhile, from the perspectives of air quality and industrial structure optimization, the influencing mechanism of green technology innovation on employment is deeply analyzed. The results reveal that all kinds of green technology innovation can significantly increase the employment level of the city, and the promotion effect is strongest in the 2nd year after the patent application. According to the results of heterogeneity analysis, key cities of environmental protection and non-resource cities are more likely to generate positive employment effects through green technology innovation. Finally, the mediation effect test model confirms that green technology innovation can promote employment by improving air quality and causing industrial structure optimization. [ABSTRACT FROM AUTHOR]

In order to explore the evolution process of regional vegetable circulation efficiency and its influencing factors, this paper uses Super-SBM model considering unexpected output and GML index to calculate the vegetable circulation efficiency of 13 provinces (cities) in Central China and its surrounding areas from 2015 to 2019, then conducts spatial autocorrelation analysis on the vegetable circulation efficiency in this region through Moran index. Finally, SPDM model is constructed to explore the spatial effect of the influencing factors on the vegetable circulation efficiency in this region. The results show that (1) the vegetable circulation efficiency of most provinces (cities) in this region is low. (2) The Global Moran's I of the vegetable circulation efficiency in this region is positive, that is, the vegetable circulation efficiency in this region shows a certain degree of spatial agglomeration effect. (3) The level of scientific and technological innovation and the degree of government support have significant positive direct and indirect effects on the efficiency of vegetable circulation in the region, the quality of workers has significant positive indirect effects, and the level of economic development and industrial structure have significant negative indirect effects. [ABSTRACT FROM AUTHOR]

Since the reform and opening up, China's urbanization level has rapidly increased. However, urban civilization construction lags behind, creating a series of problems, such as environmental pollution, further restricting the healthy and sustainable development of cities. Therefore, China has carried out top-down civilized city construction led by the government. This paper regards the "national civilized city" selection implemented by the Chinese government as a quasi-natural experiment and empirically tests the impact of government-led civilized city construction on urban green innovation and the mechanism of this impact by using the progressive difference-in-differences (DID) model based on panel data of 281 Chinese cities from 2003 to 2018. The results show that civilized city construction contributes to increasing the level of urban green innovation, which is supported by a series of robustness tests conducted through variable substitution and sample adjustment. The quantile regression results show that the higher the level of green innovation, the stronger the green innovation effect of civilized city construction. This finding indicates that the marginal effect of green innovation in civilized city construction is gradually enhanced with the gradual increase in the level of green innovation in cities. The mediating effect analysis shows that civilized city construction can provide financial support for green innovation activities by promoting the expansion of the urban investment scale, which, in turn, increases the level of urban green innovation. In addition, environmental regulation can strengthen the promoting effect of civilized city construction on green innovation. These findings hold important theoretical and practical significance for understanding the green innovation effect of government-led civilized city construction and further leveraging the important role of government in the construction of the urban business environment as a means to promote urban investment clustering, lay the factor foundation for green innovation and strengthen the synergy between environmental regulation policies and civilized city construction policies. [ABSTRACT FROM AUTHOR]

Protecting people from air pollution is an important task for developing countries. Over the past several decades, different types of policies have been enacted in developing countries to improve air quality, with policy impact analysis being conducted as well. As for China, while there is some existing literature on the impact of short-term action on air quality, there is much less research to investigate the roles of long-term air quality control mechanism on air quality change. This paper uses the "2 + 26" city cluster in China as a case study area to particularly analyze the roles played by short-term campaigns that compose the Winter Action Plan and a long-term mechanism referred to as the environmental accountability system in pollution control. Based on econometric and descriptive statistical analyses, it is found that the implementation of the Winter Action Plan has significantly improved the air quality, and the environmental accountability system seems to have exerted an impact, as cities with better air quality appear to establish a more stringent environmental accountability system. The paper provides the following insights for other developing countries: short-term campaigns can quickly reduce pollution and protect human health, while long-term mechanisms are needed to ensure sustainable environmental protection. [ABSTRACT FROM AUTHOR]

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The free flow of factors resulting from regional integration affects not only economic and social activities between cities, but also climate and environmental changes. Under the goal of sustainable development, regional integration as a policy pathway to lower carbon intensity has rarely been clarified. In light of this, using panel data of 279 prefecture-level cities in China from 2006 to 2019, this paper treats city cluster planning as a quasi-natural experiment of regional integration and aims to discuss the impact and mechanism of regional integration on carbon intensity through difference-in-differences (DID) method, mediating effect model and moderating effect model. The following results are reached: (1) The implementation of regional integration policy effectively reduces carbon intensity, and the conclusion still holds after a series of robustness tests. (2) Total factor productivity (TFP) is the mediator of regional integration to reduce carbon intensity, and population density, technological innovation and industrial upgrading are the moderators. (3) The effect of regional integration in reducing carbon intensity varies from city location and city features. The proposed theoretical framework of regional integration affecting carbon intensity, containing mediator and moderators, not only enriches the theoretical research in the field of environment and region, but also provides a new policy path for exploring sustainable development. Therefore, it is necessary to build urban agglomerations integrating the concepts of green, low carbon, intensive and efficient. [ABSTRACT FROM AUTHOR]

Evaluating the effect of low-carbon city pilot (LCCP) policy is of vital importance for urban ecological construction. This study aims to deeply explore the effect of LCCP policy on urban air pollutant PM2.5. Using China's prefecture-level panel data during 2004–2020, this research adopts the difference-in-difference model to evaluate the effect of LCCP policy on urban PM2.5 and considers the heterogeneity of policy effect from the perspective of urban resource endowment and industrial characteristics. Also, this study analyzes mechanism affecting urban PM2.5 by mediation effect model. In addition, this paper explores the spatial spillover effect of the LCCP policy. The results indicate that the LCCP policy has significantly reduced urban PM2.5. The heterogeneity analysis shows that the effect of LCCP policy in declining resource-based cities is the largest, followed by regenerated resource-based cities and non-resource-based cities. The effect of LCCP policy on PM2.5 in non-old industrial-based cities is greater than that in old industrial-based cities. The impact mechanism analysis indicates that the effect of LCCP policy could be achieved through promoting technological innovation, public transportation, and industrial agglomeration. The LCCP policy has reduced the PM2.5 of neighboring pilot cities, but it has insignificant effect on neighboring non-pilot cities. [ABSTRACT FROM AUTHOR]

The traditional view is that local governments are inclined to ease environmental regulations in response to fiscal pressure (FP) and alleviate FP by sacrificing the environment for economic development (ED). This paper takes Chinese Mainland resource-based cities (RBC) as the research sample but draws different conclusions. The research results are as follows: firstly, for RBC, although FP reduces environmental pollution (EP), it is not conducive to ED. Compared with non-resource-based cities (NRBC), the economic negative effect of FP in RBC is more obvious. Secondly, FP is detrimental to ED by reducing EP, and RBC have not sacrificed the environment to promote ED in the context of FP. This paper summarizes that the development path of RBC should be "optimizing government behavior → increasing FP → improving environmental quality → reducing ED level." Thirdly, the impact of FP on cities with slower economic growth and smaller economic gap is greater, and the impact of FP on cities with better environment is more obvious. This paper argues that facing FP, RBC in China will not trade EP for ED; at the same time, we suggest RBC in other countries in the face of the FP, not only thinking of promoting ED at the expense of the EP and ease the FP, but also the development of green ecological requirement, overall consideration of the relationship between EP and ED, and then achieve green and sustainable ED without degrading the environment as far as possible. [ABSTRACT FROM AUTHOR]

Understanding intercity linkage patterns is of great importance to understanding urbanization. With advancements in transportation, communication technology, and the availability of big data, the "death of distance" concept has gained significant attention. This paper analyzes the asymmetric spatial intercity linkage network in China's economically developed YRDR based on big data derived from Spring Festival (SF) migration. The aim is to explore the determinants of these linkages considering multivariate distance factors. The findings indicate a notable pattern of asymmetry in the intercity linkage network of the YRDR between core and non-core cities. The spatial decay effect of geographic distance on intercity asymmetry linkage is observed. Despite technological advancements, geographic distance remains the most influential and decisive factor in determining intercity asymmetric linkages. While other attribute distances also play a positive role, their effects become complex when controlling for geographic distance. Understanding these attribute distances is essential in comprehending the decay effect. This study contributes to the empirical investigation of the "death of distance" debate and provides a practical analytical framework for analyzing the drivers of intercity linkage patterns. It enhances our understanding of intercity spatial linkages within the context of urbanization in China and offers valuable insights for formulating development policies in the YRDR. [ABSTRACT FROM AUTHOR]

This paper aims to detail the relationships between urbanization, industrialization, the innovation ability of cities and local air quality in 284 cities in China using annual data. For the empirical outputs, the panel quantile regression analysis, which considers the heterogeneous nature of the data set, is employed. Initial findings indicate that (i) urbanization and industrialization negatively affect local air quality. (ii) Innovation capability of cities has a direct and improving impact on local air quality. Then, the paper estimates the moderating role of cities' ability to innovate in the polluting effect of urbanization and industrialization on local air quality. Remarkably, empirical evidence indicates that (iii) the innovation ability of cities also moderates the polluting impact of urbanization and industrialization on local air pollution. Based on the findings, the paper confirms the importance of both direct and moderator effects of the innovative environment in cities in tackling air pollution. [ABSTRACT FROM AUTHOR]

Maintaining the supply of multiple ecosystem services of cultivated land is directly concerned to the sustainable development of human society. The ecological compensation of cultivated land is an important measure which has been major strategy to promote ecological protection of cultivated land and ensure food security in China. Although the cultivated land is immovable, when the grain transfer from surplus to poor areas, the cultivated land resources are reallocated and the corresponding ecosystem services are spilt. This paper constructs a model to quantify cultivated land resources flows hidden in the grain, calculates the compensation standard, and quantifies the compensation amount by building the eco-compensation mechanism. The typical integrated region in China, the Yangtze River Delta (YRD) was selected as the study area. The results show that (1) cultivated land resources in the YRD appear the characteristics of outflow in 24 cities and inflow in 17 cities, which means the former is the recipient and the latter is the payer of eco-compensation. (2) Generally, the developed cities have much more outflow of cultivated land resources than the developing cities in the YRD. And the city of Shanghai and Hangzhou, which are the best economic developed cities in the YRD, transfers into most grain and cultivated land. (3) Paddy field and dry farmland have different eco-value, so the compensation is different, respectively. Our study can enrich the perspective of cultivated land eco-compensation and proposes policy implications for improving the eco-compensation mechanism and realizing multifunctional ecological protection of cultivated land in China. [ABSTRACT FROM AUTHOR]

Studying the impact of urbanization on agricultural development in shrinking areas is important for maintaining food security and promoted agricultural development in China. Based on the measurement results of the shrinking cities in the three provinces of Northeast China, this paper selects 15 shrinking cities as the research object, and constructs a multi-dimensional index system to explore the impact of the urbanization level of the shrinking areas on the agricultural development in the region since 2007–2019, analyzes the influencing factors and their differences by using the geographically-weighted regression model and Geodetector, and proposes a targeted regulation strategy. The results show that: 1) overall, there is a negative correlation between the urbanization level and the agricultural development level in the contracted areas of the three northeastern provinces. The urbanization level in these areas has a certain negative impact on the overall level of agricultural development; 2) regarding the time dimension, the impact of urbanization level on the agricultural development level in the contracted areas of the three northeastern provinces gradually increases over time; 3) regarding the spatial pattern, the overall impact of shrinking urbanization levels in the three provinces of Northeast China on the agricultural development shows a significant distribution pattern of high in the east and low in the west; 4) the total population and natural population growth rate at the end of the year were the main factors influencing a certain level of urbanization on agricultural development in the shrinking cities while population density and the urban fixed asset investment rate were the secondary factors; and 5) the main reasons why the level of agricultural development in different cities was affected by the level of urbanization were different. However, they can be categorized into areas of population loss and spatial construction, which can be further divided into area of population loss in the northeast, areas of negative population growth in the west, and areas of urban spatial change in the south. According to the causes of the impact, this paper adopted targeted regulation strategies and formulated relevant policies and solutions that cater to local conditions. [ABSTRACT FROM AUTHOR]

Over the past two decades, China has undergone a rapid urbanization process. As such, determining the current status of the quality of life in Chinese cities and how to improve it has become a common concern for all sectors of Chinese society. This paper employs a combination of city-level macro data and individual-level micro data to construct a quality of life evaluation system that contains 9 dimensions and 35 secondary indicators. The quality of life of 194 cities in China has been further assessed using the Pena distance method (DP2). The study found that there are significant regional differences in the quality of life in Chinese cities, with the quality of life in China's large cities being significantly higher than that in small and medium-sized cities. The analysis of Ivanovic discrimination coefficient shows that social security, culture and education and infrastructure are the most important factors affecting the quality of life in Chinese cities. Spatial mismatch analysis reveals that the quality of life and subjective well-being differ significantly in Chinese cities. In addition, this paper provides policy recommendations to improve the quality of urban life in China and to reduce the imbalance in the quality of life between regions. [ABSTRACT FROM AUTHOR]

With rapid urbanization, the economic agglomeration within cities is associated with severe air pollution. Urban spatial structure adjustment has been recognized as an effective strategy for improving air quality. However, the research on how to mitigate air pollution originating from economic agglomeration through urban spatial structure adjustment is unclear. Therefore, based on panel data for municipal cities in the Yangtze River Delta (YRD) region during 2008–2018, this study empirically tests the transmission mechanisms among economic agglomeration, urban spatial structure, and air pollution. We use the combination of the social network analysis (SNA) and two-stage least squares (2SLS) methods to verify the effect of economic agglomeration on air pollution. Economic agglomeration's indirect effect on air pollution through urban spatial structure is further tested using mediating effect model and cross-section comparisons. When exploiting an exogenous order rank of node city importance for instrument variable (IV), our finding shows that increasing economic agglomeration by 10% increases air pollution by 12%. In addition, in market forces, monocentricity brings about economic agglomeration's pollution effect, while polycentricity leads to agglomeration's environmental benefits improvement. However, a government-led exogenous polycentricity greatly mitigates economic agglomeration's pollution effect, while in cities with monocentricity, agglomeration slightly increases air pollution. Compared with market power, our paper stresses government intervention in promoting urban spatial structure in terms of polycentric development could be more helpful for improving agglomeration's environmental benefits in China's YRD region. [ABSTRACT FROM AUTHOR]

An urban subway network system is a complex public transportation system. To compare rail transit braking digital command control strategies based on neural network, this article analyzes and studies the characteristics of subway vehicle driver controllers and their design methods from three aspects: mechanical, electrical and software-assisted design. The learning rule of the BP neural network is called the mentor system learning rule, which is a kind of error-correcting algorithm. In the learning and training process, the expected output value needs to be given. The weights and thresholds of the BP neural network are optimized by selecting the parameters of the SA algorithm. The search method of SA is heuristic, and it has the following advantages: The selection of the initial solution does not affect the optimal solution. The simplified model extracts the core data processing individual analysis. In this paper, the physical data are extracted from the physical entity operation process for analysis, and the twin model is established to extract the twin data for analysis. This paper uses the characteristics of physical data to test the modeling effect and utilizes the twin data to carry out algorithm experiments on physical data. The ultimate goal is to use twin data to predict the state information of physical entities. The network error in the scheme designed by the article is 6%. The smooth implementation of this research constitutes an important reference for the design of subway train network control systems in other cities in China. Therefore, this research has great application value. [ABSTRACT FROM AUTHOR]

The Clean Heating Policy aims to solve the problems of excessive energy consumption and severe air pollution caused by central heating in northern China. Whether this policy can effectively reduce carbon emissions remains unexplored. Using panel data representing 65 cities in northern China from 2010 to 2019, this paper constructs a dynamic spatial DID model to empirically study the carbon reduction effect of the Clean Heating Policy and its influence channels. The results are summarized as follows. First, the Clean Heating Policy can significantly reduce carbon emissions, and this conclusion holds after multiple robustness tests. The policy has a lag effect, but its spatial spillover effect and long-term effect are not significant. Second, the carbon reduction effect of the Clean Heating Policy is mainly achieved by optimizing the energy structure and improving the thermal efficiency of heat consumer terminals. Third, the carbon reduction effect varies by city and emission field. It is significant only in low-subsidy cities, high-carbon cities, and household fields. Fourth, there is a synergistic reduction relationship between the Clean Heating Policy and the low-carbon city policy. Based on the results of this paper, we propose policy implications, such as promoting policies in multiple ways and improving subsidy efficiency, and provide a reference for other countries. [ABSTRACT FROM AUTHOR]

To achieve the goal of urban carbon dioxide emission reduction, how to increase carbon sequestration has become a top priority. The biological sink is mainly divided into green carbon sink and blue carbon sink. Coastal cities have two kinds of carbon sinks. There, the study of carbon sinks in coastal cities is the primary choice to cope with climate change. Therefore, this study chooses coastal cities with primary industries including agriculture, fishery, and forestry as the study subjects. The LMDI (Log-Mean Divisia Index) method and multiple regression prediction models were used to explore the low-carbon countermeasures which increase urban net carbon sink from the perspective of influencing factors and future potential. The study found that the average output value of employees in the primary industry is the main driving factor, and the change in the purchasing power of unit carbon sinks and the change in the proportion of employees in the primary industry have inhibited the increase in net carbon sinks. Projections based on the primary industry's output and afforestation area as independent variables show an overall upward trend in net carbon sinks, reaching 15.70 million tons of net carbon sinks in 2060, offsetting 10–20% of total carbon emissions in the same year. Based on the calculation results, this paper puts forward some corresponding countermeasures to increase carbon sinks. This paper provides a theoretical reference for the low-carbon development of coastal cities in China, and the strategies can be also expanded to other cities with similar resources around the world. [ABSTRACT FROM AUTHOR]

It will contribute to ameliorating the national carbon trading system and further benefit the realization of China's carbon peaking and carbon neutrality goals through in-depth study and summarize the effectiveness of carbon trading policy implementation in pilot areas. Based on the multi-phase difference-in-differences approach and synthetic control method, this paper utilizes China's provincial panel data from 2006 to 2020 to comprehensively assess the Porter effect (including the economic and green innovation effects) and carbon mitigation effect of carbon trading policy from the overall and local perspectives. Then the robustness test and mechanism analysis are carried out. The findings show that: (1) from the overall effect, the carbon trading policy brings a noticeable carbon mitigation effect and Porter effect, and the intensity of the impact keeps changing over time; (2) there is significant heterogeneity in the local effects of this policy on the eight pilot provinces and cities, with only Chongqing obtaining both the Porter effect and the carbon mitigation effect, while the rest of the regions do not yield the triple dividend of economic, environmental, and green innovation simultaneously; (3) there are much more prominent environment and green innovation effects in the developed regions, while the underdeveloped ones have better economic development and no green innovation effect; (4) the policy can bring environmental and economic dividends through energy structure optimization. However, due to the carbon rebound effect, stimulating green innovation pathways can only boost the economy while carbon emissions increase instead. The research conclusions can provide the decision support and policy direction for policies related to China's carbon market. [ABSTRACT FROM AUTHOR]