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Urban air pollution is a prominent problem related to the urban development in China, especially in the densely populated urban agglomerations. Therefore, scientific examination of regional variation of air quality and its dominant factors is of great importance to regional environmental management. In contrast to traditional air pollution researches which only concentrate on a single year or a single pollutant, this paper analyses spatiotemporal patterns and determinants of air quality in disparate regions based on the air quality index (AQI) of the Yangtze River Delta region (YRD) of China from 2014 to 2016. Results show that the annual average value of the AQI in the YRD region decreases from 2014 to 2016 and exhibit a basic characteristic of 'higher in winter, lower in summer and slightly high in spring and autumn'. The attainment rate of the AQI shows an apparently spatial stratified heterogeneity, Hefei metropolitan area and Nanjing metropolitan area keeping the worst air quality. The frequency of air pollution occurring in large regions was gradually decreasing during the study period. Drawing from entropy method analysis, industrialization and urbanization represented by per capita GDP and total energy consumption were the most important factors. Furthermore, population agglomeration is a factor that cannot be ignored especially in some mega-cities. Limited to data collection, more research is needed to gain insight into the spatiotemporal pattern and influence mechanism in the future. [ABSTRACT FROM AUTHOR]

Concerns regarding urbanization impacts on floods gradually moved from end-of-pipe solutions, based on open channel hydraulics improvement, to imperviousness ratio limiting and then to land use control and to integrated planning at local and large scale levels. The Niushou River basin is one of the fastest urbanizing areas in Nanjing City, East China, however, the high urban land percentage has leaded to series of flooding events. The paper aims to reveal the impact of imperviousness ratio, patterns and drainage system on flooding areas based on the unit of catchment and Storm Water Management Model (SWMM). The following conclusions were reached. 1) The ratio or spatial characteristics of the impervious surface affected the runoff volumes and associated floods areas. Despite the well-established drainage system, the high imperviousness ratio, particularly clustered pattern in locations such as hydrological sensitive zones aggravated the flooding tension across the basin. 2) The poor drainage hydraulic efficiency in local areas, and the lack of integral processes of infiltration, yield, storage and discharge in local catchment and larger basin are also significant factors. 3) The Niushou River basin development should improve the drainage transformations from a single local, short-term drainage process into integral, elastic processes of infiltration, yield, storage, and discharge. [ABSTRACT FROM AUTHOR]

China is in a transitional period between urban renewal and industrial change. In this period, the focus has been on the suburbanization of enterprises and land transformation in old industrial areas, particularly areas with chemical industries. A life cycle theoretical framework was established to develop chemical industrial zones in the context of urban expansion and land function conversion. The long-term historical processes and mechanisms that transformed a typical old chemical industry area along the Yangtze River, Yanziji Area of Nanjing City were unveiled and comparatively analyzed. The study found that the entire life cycle of the case study area was formed through the combined action of different influencing factors. Traditional industrial location factors played important roles during the rise and continuity of the chemical industry zone, while unconventional environmental regulations and government policies drove its decline and transformation. In the transformation of the old chemical zone, the renewal and redevelopment of industrial land into higher-value residential land is a key link determining the feasibility of government fund compensation and the circulation of capital. These findings demonstrate that regional control and environmental regulation play crucial roles in determining the location of polluting industries and the renewal of urban industrial areas. This research enhances the understanding of the development history and reconstruction of chemical industry clusters and plots within megacities at a finer geographic scale. [ABSTRACT FROM AUTHOR]