Abstract
ABSTRACT Introduction: In-use product and material stocks are the amount of concerned manufactured products and materials in active use, and are essential components of urban ecosystem. Methods: This study estimates the dynamic in-use stocks of steel-containing products and steel in the city of Xiamen, China, during 1980–2015 by applying a bottom-up accounting approach. We incorporate 55 categories of steel-containing products that are classified into five end-use sectors (i.e., buildings, infrastructure, transportation equipment, machinery, and domestic appliances). Outcomes and Discussion: In-use stocks of 51% of the studied products kept increasing during 1980–2015, especially after 2000. Steel stocks have grown up to 4.9 ± 1.4 tons per capita (t/cap) in 2015, from 0.5 ± 0.2 t/cap in 1980. Buildings are the largest reservoirs, although its share decreased from 89% in 1980 to 68% in 2015. The dynamic spatial distribution indicates that steel stocks gradually expanded from urban core to suburban areas. Conclusion: Theresults help to explore how a city’s urbanization is sustained by the in-use stocks growth. In-use steel stocks, of which the growth is highly correlated to and probably driven by the population growth, GDP increase, and urban built-up area expansion, may serve as a supplementary indicator for urbanization.
Highlights
In-use product and material stocks are the amount of concerned manufactured products and materials in active use, and are essential components of urban ecosystem
We analyze the correlations between per capita in-use steel stocks (Sp) with three socio-economic variables and the results show that population density (PD) (R2 = 0.98, p < 0.001), per-capita gross domestic product (PGDP) (R2 = 0.94, p< 0.001), and urban built-up area (UBUA) (R2 = 0.92, p < 0.001) are all well correlated with Sp (Figure 5)
The results show that 51% of the steel-containing products demonstrate continuously increasing pattern in recent years
Summary
In-use product and material stocks are the amount of concerned manufactured products and materials in active use, and are essential components of urban ecosystem. Speaking,inuse stocks are the amount of tangible manufactured products (e.g., buildings and passenger cars) that are in active use or the amount of materials (e.g., steel or aluminum) contained in in-use stocks of products (Kapur and Graedel 2006). It should be noted that it is products, instead of materials, that directly provide the functions and services demanded by human society It is the human needs for the functions and services provided by product stocks that drive the dynamic process of accumulation and discard of products (Gerst and Graedel 2008; Chen and Graedel 2015). In-use stocks of products, especially from per-capita or per-household perspective, can serve as measurements of living standard in a city (Chen and Graedel 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
