Guoqin Zhang

Urbanisation and human health in China: spatial features and a systemic perspective

Background, aims and scopeCurrent studies have paid little attention to the dynamism in urban spatial expansion and its possible environmental and health effects or to the health effects of rapid urban environmental change at different points along the urbanisation gradient. This study adopts a public health ecology approach to systematically understand the relationship between urbanisation, urban environmental change and human health in China.MethodRemote sensing image analysis, based on night light data at five different time periods in recent decades, was used to determine changes to the overall urban area. Through a review of the evidence on the relationships between environmental health, urbanisation and health, we advance a pathway framework for explaining urban human health ecology. The Spearman rank correlation coefficient was used to measure the correlation between disease prevalence and urbanisation level, adding a further dimension to a systemic understanding of urban health.Results and conclusionsUrban areas have been increasing spatially, but unevenly, in recent decades, with medium and small cities also expanding rapidly in the past decade. Urbanisation and urban expansion result in changes to land use/coverage change, the urban environment and the residents’ lifestyle, which result in human health problems. Regions with the highest urbanisation level were more inclined to have a high prevalence of chronic disease in recent decades. An ecological public health approach provides insights into the multiple types of data which need to be routinely collected if human disease is not to become a barrier to social and economic development.

Urbanization and health in China, thinking at the national, local and individual levels

BackgroundChina has the biggest population in the world, and has been experiencing the largest migration in history, and its rapid urbanization has profound and lasting impacts on local and national public health. Under these conditions, a systems understanding on the correlation among urbanization, environmental change and public health and to devise solutions at national, local and individual levels are in urgent need.MethodsIn this paper, we provide a comprehensive review of recent studies which have examined the relationship between urbanization, urban environmental changes and human health in China. Based on the review, coupled with a systems understanding, we summarize the challenges and opportunities for promoting the health and wellbeing of the whole nation at national, local, and individual levels.ResultsUrbanization and urban expansion result in urban environmental changes, as well as residents’ lifestyle change, which can lead independently and synergistically to human health problems. China has undergone an epidemiological transition, shifting from infectious to chronic diseases in a much shorter time frame than many other countries. Environmental risk factors, particularly air and water pollution, are a major contributing source of morbidity and mortality in China. Furthermore, aging population, food support system, and disparity of public service between the migrant worker and local residents are important contributions to China’s urban health.ConclusionsAt the national level, the central government could improve current environmental policies, food safety laws, and make adjustments to the health care system and to demographic policy. At the local level, local government could incorporate healthy life considerations in urban planning procedures, make improvements to the local food supply, and enforce environmental monitoring and management. At the individual level, urban residents can be exposed to education regarding health behaviour choices while being encouraged to take responsibility for their health and to participate in environmental monitoring and management.

Carbon footprint analysis of the Bus Rapid Transit (BRT) system: a case study of Xiamen City

The transport sector is responsible for a large and growing share of global emissions that affect climate change. Bus Rapid Transit (BRT) systems have been identified as an efficient public transport option, but their total emissions across the entire operation chain have not been quantified. This paper proposed a carbon footprint model of the BRT system based on a life cycle assessment (LCA) approach, with three components: infrastructures, fuels and vehicles. A case study of Xiamen City was carried out to offer a broader perspective on the greenhouse gas (GHG) impact. Results showed that the total carbon footprint of Xiamens BRT system was 55,927 tCO2e per year. The main emission phases, infrastructure operations, vehicle fuel consumption and infrastructure material production, respectively, accounted for 31%, 30% and 23%. The direct emission from fuel consumption was 13,059 tCO2e per year, accounting for 23% of the total carbon footprint. Considering only direct emissions, the BRT system could achieve reductions of approximately 25,255 tCO2e per year compared to the no-build option. The carbon footprint model proved effective in identifying and measuring GHG emissions of each activity of the BRT life cycle.

Understanding the relationship among urbanisation, climate change and human health: a case study in Xiamen

The objective of this study was to explore the correlation among urbanisation, climate change and human health. Temporal variation of the prevalence of communicable diseases and the meteorological parameters were analysed, and relations among communicable diseases, meteorological parameters and socio-economic statistical data are discussed based on correlation analysis and stepwise regression. The results showed that both socio-economic development and regional climate change have effects on the prevalence of communicable diseases. Prevalence of blood-borne diseases and sexually transmitted diseases in Xiamen significantly increased during the 1990s. On the other hand, the prevalence of respiratory infectious diseases and gastrointestinal infectious diseases showed a decreasing trend with economic development. Climate has changed in the past 50 years, and particularly so in the last 30 years. The prevalence of gastrointestinal infectious diseases is linked to variation of annual average temperature and relative humidity. Annual average temperature, maximum temperature, minimum temperature and precipitation could be important determinants of the prevalence of insect-borne diseases.

Eco-efficiency of urban material metabolism: a case study in Xiamen, China

In this research, the data envelopment analysis (DEA) model of measuring the eco-efficiency of urban material metabolism has been constructed based on the urban material input and output indicators. According to the data of Xiamen from 1985 to 2007, an empirical study was conducted to measure the eco-efficiency of urban material metabolism using DEA program. The results showed a general downtrend of Xiamens eco-efficiency of material metabolism from 1985 to 2007, in which there were 15 efficient years and eight inefficient years. The eco-efficiency and urbanization rate of Xiamen was remarkably negatively correlated. Moreover, the results revealed at 4 years (1995, 2001, 2002 and 2003) there had been undesirable output slack (environmental pollution), and at 2 years (1991 and 1999) there had been desirable output slack (GDP), and at 8 years there had been input slack (water, land, food and energy), especially for water and energy. Finally, some suggestions on promoting the eco-efficiency of urban material metabolism were put forward.

Resource consumption and city size: a case study of Xiamen and implications for sustainable urbanisation

Nowadays, urbanisation has become an inevitable worldwide trend, especially in China, which is experiencing rapid urbanisation. Understanding the relationship between city size and resource consumption is necessary to achieve a transition to sustainable development. This paper took a typical rapidly urbanising city, Xiamen, as a case study to analyse relationships between resource consumption and city size in the course of rapid urbanisation. The best-fit curve estimation models were chosen for analysis. The average, derivative and elasticity functions were then solved and plotted. The results revealed different modes for resource use with city-scale growth. An availability, accessibility and scale framework was proposed for analysis, and the implications for sustainable urbanisation are discussed.

Quantifying and managing food-sourced nutrient metabolism in Chinese cities.

Food supply and consumption are critical for sustaining urban system functions, and are key determinants of the quantity and pathways of nutrient flow in cities. Nutrient elements from urban food consumption are becoming major pollutant sources in urban environments. Therefore, understanding flow magnitude and pathways, the role of a growing population, and changing dietary structure and technology in future nutrient metabolism are essential to understand cities as ecosystems and urban environmental management. Taking the city of Xiamen, a rapid urbanizing area of Southeast China as a case study, we simulated urban metabolism of three major food-sourced nutrient elements (carbon, nitrogen, and phosphorus or CNP) over 1991-2010 and environmental emissions. Impacts of future population growth, dietary habit change, and waste treatment improvement on various environments were forecast by scenario analysis. A sensitivity analysis was conducted to test how different waste treatment technologies affect environmental emissions from food-sourced nutrients. Our results show that the food-sourced CNP had various metabolic fluxes through urban systems, with carbon mostly emitted into the air and nitrogen and phosphorus mostly discharged into landfills and water. Population growth and dietary structure change will accelerate increases of nutrient emissions to the environment, whereas enhancing current waste treatment technology can just alter emissions to different environments. Based on the results, we discuss how food-sourced nutrient metabolism can be better managed, to enhance connectivity between cities and their hinterlands and maintain environmental emissions within the carrying capacity of the cities.

Characterizing Urban Household Waste Generation and Metabolism Considering Community Stratification in a Rapid Urbanizing Area of China.

The relationship between social stratification and municipal solid waste generation remains uncertain under current rapid urbanization. Based on a multi-object spatial sampling technique, we selected 191 households in a rapidly urbanizing area of Xiamen, China. The selected communities were classified into three types: work-unit, transitional, and commercial communities in the context of housing policy reform in China. Field survey data were used to characterize household waste generation patterns considering community stratification. Our results revealed a disparity in waste generation profiles among different households. The three community types differed with respect to family income, living area, religious affiliation, and homeowner occupation. Income, family structure, and lifestyle caused significant differences in waste generation among work-unit, transitional, and commercial communities, respectively. Urban waste generation patterns are expected to evolve due to accelerating urbanization and associated community transition. A multi-scale integrated analysis of societal and ecosystem metabolism approach was applied to waste metabolism linking it to particular socioeconomic conditions that influence material flows and their evolution. Waste metabolism, both pace and density, was highest for family structure driven patterns, followed by lifestyle and income driven. The results will guide community-specific management policies in rapidly urbanizing areas.

Analysis of lung cancer gender differences and age structure in the high prevalence areas of Xiamen

The incidence rate and mortality of lung cancer continuously rise, and lung cancer is one of the leading causes of cancer death deaths. Detecting the high prevalence areas of lung cancer can effectively provide clue for detecting its influential factors. Taking the incidence rate of lung cancer in Xiamen as an example, this paper adopted Morans I and Getiss G statistics to detect global correlation characteristics and hot spot areas of the incidence rate of lung cancer based on street (town) scale and district scale. And the incidence rate of lung cancer in different gender and ages were analysed in hot spot areas. The result shows that spatial correlation characteristics of the incidence rate of lung cancer based on district scale are not obvious, and spatial correlation characteristics of the incidence rate of lung cancer based on street (town) scale are obvious, and the hot spot areas of the incidence rate of lung cancer are detected. Another result shows that the incidence rate of lung cancer in different gender and ages is different in different hot spot areas. The conclusion is that it is very important to select a proper spatial scale for the research of the incidence rate of lung cancer. And the main age groups of lung cancer are 50∼59 years old, 60∼69 years old and 70∼79 years old, and lung cancer incidence of men is higher than women.

Analysis of socio-economic driving forces on built-up area expansion in Xiamen

Based on grey relational analysis and stepwise regression, this study analysed the socio-economic driving forces of Xiamen since the reform and opening of China. The research aimed to explore the deep dynamic mechanism of urban space expansion of Xiamen and provide scientific support for its sustainable development. The results indicate resource consumption factors and population factors have had a significant driving effect on the expansion of built-up area, and have contributed more than the economic development factors. It was revealed that the main urban socio-economic driving forces have gradually changed during the middle and late stage of urbanisation, and the city has also shifted from an original construction and developing city type into a more spatially stable, developed city type.