Impact of urban agglomeration construction on urban air quality–empirical test based on PSM–DID model

Abstract

Urban agglomerations have become a new trend in the development of urbanization and regionalization in the world today. The construction of urban agglomerations has brought rapid economic development as well as a series of ecological and environmental problems, especially the impact on urban air quality. How to understand and evaluate the impact of urban agglomeration construction on air quality is a key issue that requires attention. City cluster construction is equivalent to a "quasi-natural experiment". This study empirically examines the impact of urban agglomeration construction on air quality in southwest China by constructing a PSM–DID model. It is found that: (1) City cluster construction has significantly improved urban air quality in urban clusters with lagging and forward-looking effects on air quality. (2) In terms of influencing factors, the level of economic development considerably improves the air quality of urban cluster cities, the industrial structure severely deteriorates the air quality of these cities, and meteorological factors highly affect their air quality. Among them, average annual urban rainfall significantly reduces urban air pollutant concentrations in urban clusters, average annual temperature significantly increases urban air pollutant concentrations, and average annual wind speed can reduce urban air pollutant concentrations. (3) Urban agglomerations are spatially heterogeneous in their impact on air quality. In this context, the topographical conditions and the level of development of urban agglomerations have a non-negligible influence on pollutant concentrations. (4) The distribution pattern of air quality pollutant concentrations in each urban agglomeration is unstable, and there are large differences in these concentrations between different urban agglomerations.

The Opening of High-Speed Rail and Economic Growth: The Moderating Role of Government Efficiency and Innovation Environment

“…Second, HSR opening can reshape the spatial structure of cities, improve resource allocation efficiency, create investment opportunities within the city, increase venture capital, and reduce innovation costs [21]. Finally, HSR opening can accelerate the speed of information flow, enhance the accessibility of knowledge, and promote the transfer and diffusion of knowledge and technology between regions, providing crucial support for the conduct of innovation activities [25,26]. Moreover, HSR opening can drive the innovation development of high-tech industries (such as science and technology, finance, and information) in cities along the rail line and the surrounding areas, providing necessary support and guarantees for optimizing the urban innovation environment [27].…”

“…Innovation entities can effectively cultivate and demonstrate innovation vitality, driving the enhancement of regional innovation capability and economic growth, only within a certain innovation environment [41]. Existing research has mainly focused on the direct impact of high-speed rail opening on the innovation environment, suggesting that high-speed rail opening can optimize resource allocation along its route, improve the layout of industrial structures, accelerate the flow of innovation elements within the region [8], and meet the demand for high value-added innovation relying on face-to-face communication [42], thus exerting a favorable influence on the creation of an innovative environment [26].…”

Influential Nodes Identification in the Air Pollution Spatial Correlation Weighted Networks and Collaborative Governance: Taking China’s Three Urban Agglomerations as Examples

“…With the rapid development of urban agglomerations, China's economic aggregate has grown rapidly. However, it has also brought a series of ecological and environmental problems [12]. Currently, the level of air pollution in the Beijing-Tianjin-Hebei, the Pearl River Delta, the Yangtze River Delta and other urban agglomerations with relatively high levels of economic development is significantly higher than the national level [13].…”