Center for Industrial Ecology, School of Forestry and Environmental Studies, Yale University , New Haven, Connecticut 06511, United States.
Environ Sci Technol. 2015 Mar 3;49(5):3048-55. doi: 10.1021/es504353s. Epub 2015 Feb 13.
Determinations of in-use material stocks are useful for exploring past patterns and future scenarios of materials use, for estimating end-of-life flows of materials, and thereby for guiding policies on recycling and sustainable management of materials. This is especially true when those determinations are conducted for individual products or product groups such as "automobiles" rather than general (and sometimes nebulous) sectors such as "transportation". We propose four alternatives to the existing top-down and bottom-up methods for estimating in-use material stocks, with the choice depending on the focus of the study and on the available data. We illustrate with aluminum use in automobiles the robustness of and consistencies and differences among these four alternatives and demonstrate that a suitable combination of the four methods permits estimation of the in-use stock of a material contained in all products employing that material, or in-use stocks of different materials contained in a particular product. Therefore, we anticipate the estimation in the future of in-use stocks for many materials in many products or product groups, for many regions, and for longer time periods, by taking advantage of methodologies that fully employ the detailed data sets now becoming available.
使用中材料存量的测定对于探索过去的材料使用模式和未来情景、估算材料的报废流动，从而指导材料的回收和可持续管理政策是非常有用的。当这些测定是针对个别产品或产品组（如“汽车”）而不是一般（有时是模糊的）部门（如“运输”）进行时，情况尤其如此。我们提出了四种替代现有自上而下和自下而上方法的替代品，选择取决于研究的重点和可用数据。我们用汽车中的铝使用情况说明了这四种替代品的稳健性、一致性和差异性，并证明了这四种方法的适当组合可以估计所有使用该材料的产品中该材料的使用中存量，或特定产品中包含的不同材料的使用中存量。因此，我们预计将通过充分利用现在可用的详细数据集的方法，在未来对许多产品或产品组中的许多材料、许多地区和更长时间内的使用中存量进行估计。
