The effects of urbanization on PM2.5 concentrations in China's Yangtze River Economic Belt: New evidence from spatial econometric analysis

China's accelerating urbanization has intensified the contradiction between city development and atmospheric environment. Fine particulate matter (PM2.5), as the primary form of air pollution, seriously threatens human health, and negatively impacts atmospheric visibility and the climate. As its study area, this paper takes China's Yangtze River Economic Belt (YREB), which comprises three crucial urban agglomerations and has suffered frequent severe haze episodes in recent years. To achieve the coordinated development of urbanization and air quality in YREB, it is of practical significance to research the effect of urbanization on PM2.5 concentrations. Using a prefecture-level panel dataset of YREB over the period 2003-2014, this paper adopts spatial econometric techniques to investigate the spatial dependence pattern of PM2.5 concentrations and analyze the effects of population urbanization, land urbanization, and economic urbanization on PM2.5 concentrations in YREB both empirically and theoretically. Results indicate that PM2.5 concentrations in YREB exhibit obvious global positive spatial autocorrelation, and, from the local perspective, high-high clustering regions expand from the lower reaches of YREB to the middle reaches. There is no significant U-shaped, N-shaped, inverted U-shaped, or inverted N-shaped relationship between economic urbanization and PM2.5 concentrations in YREB, but an incremental linear linkage exists. Population urbanization exerts a significant and positive effect on PM2.5 concentrations in YREB, while land urbanization shows a negative but insignificant influence. By contrast, population urbanization is a more important influencing factor on PM2.5 concentrations in YREB than is land urbanization. In addition, the empirical evidence denotes that the population scale and secondary industry have promoting effects on PM2.5 concentrations, whereas foreign direct investment has an inhibitory impact, and technology level shows no significant influence. (C) 2019 Elsevier Ltd. All rights reserved.