There are a wide variety of sustainability indicators currently in use, whose #PRIMA-1MET randurls[1|1|,|CHEM1|]# geographical targets vary from global/international scale to national and local/city level. The representative indicators for the national and global levels include, but are

not limited to, the United Nations Commission on Sustainable Development (UNCSD) indicators, the environmental sustainability index (ESI), and the human development index (HDI). The UNCSD Indicators for sustainable development is a set of 58 indicators with flexible adaptation at the national level. The indicator framework uses four dimensions (society, environment, economy, and institutions) and each dimension is further divided into themes, sub-themes, and indicators. For instance, one theme of the environmental dimension is the atmosphere, which is divided into three sub-themes: climate change, ozone layer depletion, and air quality. Each sub-theme has one or more indicators; in the case of climate change,

for example, the indicator IWR 1 is greenhouse gas emissions (UNCSD 2001). The ESI, developed at Columbia and Yale universities, is designed to utilize the following five components: environmental systems, environmental stresses, human vulnerability, social and institutional capability, and global stewardship. Each component has a group of so-called indicators (21 in total) and each indicator has a set of variables, for a total of 76 variables (Esty et al. 2005). The ESI is the equally weighted average of the 21 indicators and five components. Etofibrate For example, air quality is one of the indicators of the ‘environmental systems’ component. This indicator has four variables: NOx concentration, SOx concentration, particulate concentration, and indoor air quality. The ESI published its environmental sustainability rankings at the country level in 2001 and 2005. The HDI considers three basic dimensions for human development: health, measured in terms of life expectancy at birth; education,

measured in terms of adult literacy and primary, secondary, and tertiary enrolment; and, finally, standard of living, measured in terms of GDP per capita (UNDP 2006). As a basic indicator, the HDI ranks countries in terms of human development. Another important feature is that the HDI has been calculated on the yearly basis since 1975. It should be stressed that indicators, such as ESI and HDI, are categorized as indicative assessment methods, aiming to analyze the relative status of sustainability or specific components of sustainability among targeted areas in the form of integrated scores, as opposed to the definitive type of assessment that attempts to argue the absolute status of sustainability, per se. At the local level, it is worth mentioning the Sustainable Seattle initiative (1998). Community members consisting of local citizens selected 40 comprehensive indicators under five large categories of environment, population and resources, economy, youth and education, and health and community.