Digital technologies represented by big data, artificial intelligence, and cloud computing are developing rapidly and integrating deeply with the real economy, and becoming a new trend and a new wave of global economic development (Ma and Zhu, 2022). As pioneers in promoting knowledge transfer, enterprise creation and economic development, cities are changing their trajectory with the "digital" revolution, and smart cities are becoming a new development model (Camboim et al., 2019). This smart transformation of cities will have significant socio-economic and livelihood impacts, which have recently been further accelerated by advances in digital technologies such as artificial intelligence and big data (Camero and Alba, 2019; Appio et al., 2019).
The concept of smart cities has evolved dynamically. Initially, cities were technology-oriented, and academic research and government practice focused on the development of information technology (Röller and Waverman, 2001). With the gradual development of smart cities, more attention has been paid to the soft power of cities, and the focus gradually shift to humanities, education and environment (Berry and Glaeser, 2005). Currently, the concept of sustainable development and green economy have been integrated into urban development, and the connotation of smart cities gradually evolved to green smart cities (Gazzola et al., 2019). In the past decade, smart city pilot policy (SCP) has been implemented around the world to build smart cities, promote the development of information, communication and media industries, enhance the management and connectivity of urban areas, and increase the social capital of cities (Nakano and Washizu, 2021). Under the support of SCP, by strengthening the infrastructure construction and application of digital technologies, smart cities can accelerate the dissemination and sharing of knowledge among various sectors and promote technological innovation, thereby improving urban productivity and economy.
It is true that smart city construction has a positive effect on economic development (Song et al., 2022). However, the nexus between smart city construction and environmental pollution is not clear. Some scholars believe that smart city construction has increased environmental pollution, but others do not. Chu et al. (2021) found that smart city construction can improve urban technology and resource allocation efficiency, and reduce environmental pollution. Xu and Yang (2022) noted that the implementation of smart city policies can strengthen the level of information technology, improve green total factor productivity, promote technological innovation and thus to reduce environmental pollution. Gao and Yuan (2021) and Guo et al. (2022) suggested that smart city construction will speed the dissemination of green technologies and improve energy efficiency, promote green economic transformation, and improve environmental quality. Monfaredzadeh and Berardi (2015) noted that the construction of smart cities may also lead to energy rebound effects that increase urban environmental pollution while promoting economic growth. Therefore, the relationship between smart city construction and environmental pollution needs to be further explored. Additionally, though previous scholars explored the environmental impact of smart city construction, they tend to think in terms of technological innovation and enterprise resource allocation, while ignoring city residents (Shu et al., 2023; Chu et al., 2021). In fact, the public is closely related to environmental protection, and their active participation plays an important role in reducing environmental pollution (Wang et al., 2023). The lifestyle of the social public will undoubtedly change as a result of smart city construction. Thus, it is necessary to include the social public in the research framework of smart city construction and the environmental pollution.
In order to narrow the research gap and provide new empirical evidence on smart city research, this research takes SCP in China as a quasi-natural experiment to systematically explore the relationship between smart city construction and environmental pollution. First, as the world's largest developing country, China is facing enormous population and urbanization pressure, and smart cities have emerged as a new development model to solve the "urban disease". Second, China's economic development has entered a critical stage of transformation from high-speed growth to high-quality growth. The pursuit of economic growth must be accompanied by a good ecological environment, and the introduction of the double carbon target will be a major test for China's economic development. Unleashing the vitality of digital technology innovation through smart city construction is important for promoting regional economic growth and achieving a qualitative transformation in economic development (Wu et al., 2023). Consequently, SCP in China is a very good research object.
This research aims to answer the following questions. Can SCP reduce pollutant emissions and improve environmental quality? If so, what are the mechanisms by which SCP reduces pollution? Does the impact of SCP on environmental pollution vary according to the city's geographical location, administrative rank, human capital, and information infrastructure? Will surrounding cities be affected after the implementation of SCP? In this research, we will use SCP implemented in 2012, 2013, and 2014, respectively, as quasi-natural experiments and use a multi-temporal DID approach to empirically test the impact of SCP on environmental pollution and associated research questions.
Compared with existing literature, the possible marginal contributions of this research are as follows. First, some scholars have focused on the effects of smart city construction on carbon emissions, and argued that SCP can promote green and low-carbon urban development (Cheng et al., 2022). In this research, the entropy value method is used to construct a comprehensive index of environmental pollution to explore the effects of SCP on multiple dimensions of the environmental pollution. Second, extant studies tend to analyze the mechanism of SCP's impact on the environmental pollution from the enterprise and urban meso levels, while ignoring the role of urban residents. In this research, we incorporate public environmental concern into the research framework, providing a new perspective on the specific ways in which SCP affects the urban environment. Finally, extant research ignores the impact of SCP on the surrounding urban environment. That is, it ignores to explore the spatial spillover effects of SCP, which may lead to a less in-depth understanding of the policy effect. This research further investigates the spatial spillover effects of SCP, which providing new insights into the effect of SCP.
The remainder of the paper is organized as follows. We review the literature and introduce policy background in Section 2. Section 3 describes the data and research model. Section 4 reports the regression results, and a series of robustness tests. Section 5 presents the results of mechanism tests, heterogeneity analysis, and spatial spillover effects. The final section provides a discussion of the findings and points out limitations.