Urban ecosystem health assessment based on emergy and set pair analysis—A comparative study of typical Chinese cities

Regarding various energy and materials flowing in the urban ecosystem and the merit of emergy as an embodied energetic equivalent for integrated ecological economic evaluation, an evaluation framework of emergy-based urban ecosystem health indicators (UEHI_em) was established in view of five aspects including vigor, structure, resilience, ecosystem service function maintenance and environmental impact to depict the urban ecosystem health states. Further, set pair analysis (SPA) was employed to assess the urban ecosystem health level based on the UEHI_em, by which the approximate degree of real index set to the optimal one was defined and evaluated to describe the relative health state of the concerned urban ecosystems. Choosing twenty typical Chinese cities in 2005 as cases, we evaluated and compared their urban ecosystem health levels based on UEHI_em and SPA. The results showed that health levels of Xiamen, Qingdao, Shenzhen and Shanghai are pretty well, while those of Wuhan, Harbin, Yinchuan, Beijing and Urumchi are relatively weak. Moreover, the relative health levels were analyzed by SPA to discern the influences of the mentioned five aspects on the UEHI_em. It is concluded that emergy synthesis combined with SPA can serve as an effective relative-measure to compare different ecosystem health levels of urban ecosystems.     

Ecological network and emergy analysis of urban metabolic systems: Model development,and a case study of four Chinese cities

Analysis of the structure and function of urban metabolic systems is an important goal of urban research. We used network pathways and network utility analysis to analyze the basic network structure of the urban metabolic system and the complex ecological relationships within the system, providing a new way to perform such research. Using four Chinese cities as examples, we developed an ecological network model of the urban metabolic system. By using network pathway analysis, we studied the changing relationships between metabolic length and the number of metabolic pathways, and between metabolic length and reachability. Based on the distribution of the number of metabolic pathways, we describe the basic structure and intercompartment relationships of the system. By using the sign distribution in the network utility matrix, we determined the ecological relationships and degree of mutualism between the compartments of the system. The basic components of the system consisted of the internal environment, the external environment, and the agricultural, industrial, and domestic sectors. With increasing metabolic length, the ecological relationships among the components of the system became more diverse, and the numbers of metabolic paths and their reachability improved. Although the basic network structure of the four cities was identical, the mutualism index differed. Beijing's mutualism index was superior to that of Shanghai, and much higher than those of Tianjin and Chongqing. By analyzing the structure and function of the urban metabolic system, we provide suggestions for optimizing the structure and adjusting the relationships, and propose methods for the application of ecological network analysis in future urban system research.     

Landscape fires as social disasters: An overview of ‘the bushfire problem’

The ‘landscape’, ‘bushfire’ or ‘forest-fire’ problem is exemplified by the destruction of homes and human lives by landscape fires raging out of control. The ‘problem’ involves a series of landscapes (e.g. wildland and suburb), a series of systems (e.g. biophysical system and environmental-effects system), and a series of time phases (e.g. planning phase). It is a multi-stakeholder, multi-variable, multi-scale problem. Land uses, like ‘farmland’, imply a set of specific assets and, therefore, particular perceptions of losses. In all land-use designations, at any one point, fire-proneness may be seen as a function of exposure to ignition sources (embers, burning brands or flame radiation and flame contact) and the ease of ignition. The landscape-fire problem has multiple partial ‘solutions’, not just one overall solution, and these involve social governance, land management (public and private), suppression capacity and personal preparedness. The problem needs to be addressed at multiple temporal and spatial scales in an integrated fashion for the outcome to be of maximal benefit. There will always be a residual risk of severe fire occurrence. Minimisation of residual risk requires effective land management, recurrent funding and the perpetual vigilance of all parties.     

A case study of urban heat islands in the Carolinas

Urbanization tends to aggravate the negative effects of climate. The objective of this research is to aid in the understanding of the spatial variation of urban heat islands within selected cities in North and South Carolina. This understanding will help guide efforts to cool cities in order to increase human comfort, conserve energy and resources, and reduce air pollution in both of these states.     

Environmental equity in a sunbelt city: the spatial distribution of toxic hazards in Phoenix,Arizona

Abstract

This paper examines the spatial distributions of industrial facilities emitting toxic substances in the Phoenix, Arizona metropolitan region. The analysis relies on geographic information system mapping of hazardous facilities listed in the Environmental Protection Agency's Toxic Release Inventory (TRI) to assess the spatial distribution of polluting industries in relation to the demographic composition of host neighborhoods. The research addresses four questions: (1) Are there differences between the socioeconomic characteristics of neighborhoods with and without polluting industrial facilities? (2) Is there a relationship between the volume of toxic chemicals released from industrial facilities and the socioeconomic characteristics of host neighborhoods? (3) Is there a relationship between the toxicity of the chemicals released from industrial facilities and the socioeconomic characteristics of those living in proximity? (4) Do alternative methods for determining the distribution of potentially affected populations produce different observed patterns of environmental inequities? The study concludes that there is a clear pattern of environmental inequity in Phoenix based on the location and volume of emissions of TRI facilities. Analysis of the toxicity of emissions found a more equal distribution of risk, reflecting the suburbanization of high-technology industries into predominantly white middle-class communities.     

城市地下交通联系隧道火灾人员安全疏散研究

城市地下交通联系隧道是一种新型城市地下公共交通系统,交通流量大、火灾危险性高、人员安全疏散相对困难,目前国内外尚无此类专业防火设计规范。以四川大源商业核心区地下交通联系隧道为研究对象,提出隧道主出入口、下沉庭院、防烟楼梯间及分车道、防火隔间相结合的人员安全疏散方式,出口共计61处;在此基础上运用Building Exodus数值模拟并予以对比分析,最终定量确定了火灾情况下人员安全疏散路径,进而为国内外相关工程的人员疏散设计及运营提供理论依据,并为UTLT相关防火规范的制定提供理论基础及建设性意见。     

城市垃圾生态工程处理及在我国的应用前景

首先概括了城市垃圾生态工程处理的基本方法与技术,然后通过对我同垃圾现状剖析,分析了垃圾生态工程处理在我国的应用前景。      

我国城市区域环境噪声污染分析

对我国城市区域环境噪声污染的程度、范围、分布、及构成进行了论述,并分析了其原因。结果表明,我国近期内城市区域环境噪声污染状况不会得到根本改善,目前除了应加强环境噪声的控制、管理和增加技术与经济投入外,也应修改我国现有的《城市区域环境噪声标准》。     

城市轨道交通噪声评价方法及其限值的研究

根据城市轨道交通噪声时、空分布特点及污染规律,对轨道交通噪声评价量作了分析研究,提出了列车通过时的最大声级作为城市轨道交通噪声的评价量,并根据噪声时问分布特性曲线提出了与之相对应的等效声级简易计算方法.通过对上海轨道交通3号线沿线居民区的主、客观调查,得到主观烦恼度阈值和干扰睡眠阈值,提出了适用于我国城市轨道交通的环境噪声限值(建议).     

Regional water flows – Assessing opportunities for sustainable management

Sustainable water management may strongly benefit from an integrated approach. Additionally, an integrated urban water management policy considering the various urban water flows and the possible interactions between the water sector and the remaining urban activities can benefit if based on an urban metabolism based analysis. This article assesses water flows of Lisbon Metropolitan Area considering the conventional water supply system and wastewater treatment system flows and also the hydrological cycle flows, and proposes a global set of indicators to perform a benchmarking analysis of the 18 municipalities of the region. Results highlighted the heterogeneous nature of the Metropolitan area in terms of water management – either in terms of management entities (predominantly public or municipalized), water consumption (varying from 227.4 l/hab.day in Palmela to 402.7 l/hab.day in Seixal), wastewater treatment (10 out of 18 municipalities already undergo secondary or tertiary wastewater treatments), runoff indices (depending on the municipality's level of urbanization), among other. Through the output volumes it was also assessed the potential of the municipalities to reuse wastewater for potable or non-potable urban uses, as well as the potential to harvest and harness rainwater. The main constraints to an integrated water management were identified and some potential solutions were measured and proposed even though they need further assessment, particularly in a cost-benefit perspective.