4. Overall impact assessment

4.1 General rules

Having studied the contribution of inventory flows to the various environmental impacts, the problem is as follows: let's take two systems i and i′, for which we want to compare the environmental performance of i and i′ with regard to the two indicators I and J, knowing that I is favorable to i and J is favorable to i′. The question is how to distinguish between these two systems. This kind of problem is inevitable when making decisions, but can quickly become complex when indicators and systems are multiplied.

The aim of the global impact assessment stage is therefore to explain the results of the impact analysis in a sufficiently synthetic form, while losing as little information as possible. The aim is to translate the LCA results into...