Life cycle management is quickly becoming a well-known and
often used approach for environmental management. Thanks to
Life Cycle Assessment, we are able to evaluate the environmental
impacts caused by a product or a process. A life cycle approach
involves a cradle-to-grave assessment, where the product is
followed from its primal production stage involving its raw
materials, to its end use.
The LCA methodology consists of four major steps. The first one
is the definition of the goal and scope of the analysis. This includes
the definition of a reference unit: all the inputs and outputs are
related to this reference. This is called the functional unit, which
provides a clear, full and definitive description of the product or
service being investigated, enabling subsequent results to be
interpreted correctly. The second step is the inventory analysis,
also called life cycle inventory (LCI), which is based primarily on
systems analysis treating the process chain as a sequence of subsystems
that exchange inputs and outputs. Hence, in LCI, the
product system is defined, which includes setting the system
boundaries, designing the flow diagrams with unit processes,
collecting the data for each of these processes and which emissions
will occur.
The next step is the impact assessment one. This includes the
impacts in terms of emissions and raw material depletions.
The last step is to compare with other processes offering a
similar utility and have a critical view of these previous steps. This
is referred to as the interpretation step [6–10].
In order to compare environmental impacts we need to select
impact categories.
In this paper, authors decided to use a damage approach with
the Impact 2002+ method introduced by Jolliet et al. [11]. This
method proposes a feasible implementation linking all types of life
cycle inventory results via 14 midpoint categories to four damage
categories:
- Climate change: this category corresponds to the global warming
potentials. Midpoints characterization factors for global warming
have been taken from the IPCC list [12]. The latest global
warming potentials have been used with a 500 years time
horizon. Climate change is largely dominated by CO2 emissions
and is expressed in ‘‘kgequiv. CO2’’.
- Resources: it corresponds to the extraction of minerals and fossils
fuels. It is expressed in ‘‘MJ primary non-renewable energy’’.
- Ecosystem quality: it corresponds to the aquatic and terrestrial
ecotoxicity, terrestrial acidification and nitrification, and the land
occupation. It is expressed in ‘‘PDF.m2.yr’’ (Potentially Disappeared
Fraction of species per m2 per year).
- Human health: it regroups human toxicity, respiratory effects,
ionising radiation, ozone layer depletion and photochemical
oxidation. It is expressed in ‘‘DALYs’’ (Disability Adjusted Life
Years).