Urban Environmental Sustainability Metrics: A Provisional Set

Designing or transforming urban areas into 'sustainable cities' is becoming an increasingly common vision. It is, however, an unrealizable vision without agreement on how to determine whether a sustainable city vision has been fulfilled. In this paper we define a provisional set of urban environmental sustainability metrics, chosen to cover the spectrum of issues related to urban areas, and to be drawn from data that are customarily available. We devise a display technique to communicate efficiently the results of a metrics evaluation to a variety of stakeholders. The approach is illustrated by applying the metrics set to Vancouver, Canada, an urban area that has expended considerable effort toward achieving its own environmental vision.     

The contemporary copper cycle of Asia

A regional stock and flow model for an industrial metal was developed based on the substance-flow framework. Using this model, the contemporary copper cycle of the Asian region was constructed by aggregating country-level production and import and export data for different stages of the copper cycle. The reliability and availability of data were assessed both qualitatively and quantitatively. Asia as a region is a net importer of copper. There is a significant build-up of copper in use at a rate of nearly 3TgCu/year. The per capita generation of copper waste (0.4kgCu/(capita-year)) and the rate of secondary recovery of copper are low compared with Europe and North America. Japan's rates of use, waste generation, and recycling of copper are all much larger than the continental average. A tremendous potential exists in the region to utilize the copper content of the in-use reservoir, and subsequently to enhance copper recycling rates in the future. A set of metrics for the copper cycle is suggested in order to address sustainability issues related to resource policy and the environmental management of copper.     

Anthropogenic metal cycles in China

The flows and stocks of seven important industrial metals were characterized for mainland China for several years in the dynamically changing decade of 1994–2004. One-year snapshot cycles are provided for chromium, nickel, and silver. For copper, zinc, lead, and iron, multiple-year cycles have been completed; they demonstrate that the flows of these metals into use in China doubled between 2000 and 2004. Although the Chinese per capita flows from production to disposal are mostly shown to be below the global average rate, they are increasing or are expected to increase dramatically. The metal resource efficiency is evaluated for several indicators of material flow analysis; these metrics for China are also below the global average values. The research quantitatively illustrates that China’s metal cycles may pose significant resource and environmental challenges in terms of their magnitudes and potential for growth.     

The contemporary Asian silver cycle: 1-year stocks and flows

The stocks and flows of silver throughout the Asian economy for 1997 have been quantified, with major flows examined over their entire life cycle, including mining, production, fabrication, and manufacture, product use, and waste management. By compiling the findings of 11 country-level material flow analyses, a regional analysis was created. The reliability and availability of the data varied, with the most confidence given to the earlier life stages and the most uncertainty existing later. Overall, Asia is a net importer of silver, requiring nearly 7000 Mg of silver in 1997. Approximately 2200 Mg Ag are mined, and production waste totals about 640 Mg Ag. The flow of silver into use equals 9900 Mg Ag, with a considerable build-up of 7100 Mg Ag entering in-use stock. Silver waste sent directly to the environment, in addition to landfilled waste, totals 1600 Mg Ag. Much variation exists when examining country-level silver flows on a per capita basis. India and Thailand’s fondness for silver jewelry greatly increases their silver flows into use and in-use stock. Japan’s high overall consumption reflects its high GDP per capita. Regionally, a significant potential exists to tap the silver contained in the in-use stocks and to enhance the recycling rates.     

Metal capital sustaining a North American city: Iron and copper in New Haven, CT

A detailed inventory shows that an average resident of the City of New Haven depends on a per capita capital stock of 9200 kg/c of iron and 144 kg/c of copper in the city infrastructure, buildings, transportation systems, and equipment. Of the iron stock 28% is in items such as rail cars and ships in ocean trade not permanently within the city, and 22% is devoted to receiving and delivering oil fuel to the city and its surrounding communities. Copper is principally used in the distribution of electric power and in water piping within buildings. The city's 9200 kg/c of iron stock-in-use is less than the 13,000 kg/c national average due to New Haven's lack of heavy industry and relatively small number of large buildings. The 144 kg/c of copper stock-in-use is only 58% of the overall value for the United States, but is comparable to that in cities such as Stockholm, Sweden. Attainment of a level of iron and copper services with contemporary technology in less developed countries to the level enjoyed in New Haven would require consumption of the presently identified world copper resources.     

Losses to the environment from the multilevel cycle of anthropogenic lead

As a component of a multi-level study of the anthropogenic lead cycle for year 2000 (52 countries, 8 regions, and the planet), we have estimated the lead flows in seven emission streams: tailings, slag, fabrication and manufacturing, dissipation from use, hibernation, landfilling, and dispersion following product discard. For every 1 kg of lead put into end use, 0.5 kg is lost to the environment, largely due to landfilling and dissipation from use. From the standpoint of the receiving media, 1/3 of the losses are to uncontained solids on land and 48% of the losses are to containment facilities on land. On a country basis, the largest losses occur in the United States and China, which between them are responsible for about 32% of total global lead losses. On a per capita basis, the highest lead losses occurred in the United Kingdom, Belgium-Luxembourg, and Ireland.     

Aluminum in-use stocks in China: a bottom-up study

Characterization of the in-use stocks of a resource provides a perspective on the relationship between the amount of materials providing services and the state of development of a country or region. In this regard, we have performed what we believe to be the first aluminum in-use stock study for a developing country: China in 2000 and 2005. We found the in-use stocks to be 29 Tg Al (2000) and 49 Tg Al (2005), or 23 kg Al/capita (2000) and 37 kg Al/ capita (2005). These are lower limits because data were not available for all aluminum-containing products. The 2005 per-capita figure is roughly half that of the global average in-use aluminum stock, and about one-tenth that of highly developed countries such as Japan and the United States.     

Corrosive Effects of Mixtures of Pollutants

The corrosion films that form on metals and alloys during field exposure are generally chemical mixtures. It is clear that the formation of such films requires the presence of mixtures of atmospheric corrosive gases, or of a combination of corrosive gases and atmospheric aerosol particles. Thus, laboratory experiments designed to reproduce field effects must involve mixtures of corrosive constituents. In this paper we review the mixed corrodent experiments of ourselves and others, describe the synergistic effects of mixtures of pollutants on a variety of metals, and present the necessary ingredients for experiments designed to simulate the interactive effects of atmospheric corrosive constituents.