Life cycle assessments (LCAs) are carried out to assess the environmental impact of products in each of these stages:
extracting and processing raw materials
manufacturing and packaging
use and operation during its lifetime
disposal at the end of its useful life, including transport and distribution at each stage.
Use of water, resources, energy sources and production of some wastes can be fairly easily quantified. Allocating numerical values to pollutant effects is less straightforward and requires value judgements, so LCA is not a purely objective process
Selective or abbreviated LCAs can be devised to evaluate a product but these can be misused to reach pre-determined conclusions, eg in support of claims for advertising purposes.
