Environmental Engineering Reference
In-Depth Information
criteria, for example, would make experts conduct
190 independent pairwise comparisons, whereas
considering clusters of 5 criteria would still involve
10 comparisons at the cluster level in addition to
6 comparisons in each cluster, leading to a total of
40 comparisons. Consequently, we decided not to
apply the whole procedure of the AHP but rather,
to suggest using pairwise comparisons only on
small amounts of qualitative criteria. The proposed
methodology involves a set of various procedures
that end-users may choose between, based on their
individual priorities and their project's scope.
These range from using a performance matrix,
arbitrary weights and pairwise comparisons to
applying more sophisticated procedures using
utility and cost functions, inspired by MAUT.
See the aforementioned sources for more on the
application of these procedures.
At the airport system level, we define the fol-
lowing life-cycle stages: planning, design, material
sourcing, construction, operation, maintenance,
demolition and recycling. While significant efforts
are made in the aviation industry to minimize the
environmental impacts of airport operations—for
example, current efforts to use biofuels and renew-
able sources of energy—the method proposed here
specifically addresses decisions made during the
planning and design phases of system develop-
ment. These are indeed likely to have the most
significant impacts in the long term. A true as-
sessment of an airport master plan's sustainability
should rely on a “cradle-to-grave” approach and
here we provide perspectives on the applicabil-
ity of LCA to airports and more specifically its
inclusion in this method.
This evaluation method accounts for the im-
pact of products throughout their life-cycle by
including material durability as a parameter for
sustainability evaluation. While this addition is
relatively straightforward, the authors' philosophy
is to develop an awareness of the LCA theory in en-
vironmental evaluation endeavors. As procedures
evolve and more data on materials and products
become available, comprehensive LCA studies
on specific components of an airport master plan
will become possible. At this stage, there is no
real value in conducting a full LCA of an airport
project. Indeed, the advantage of understanding
the environmental impact of the development is
clearly outweighed by the cost of gathering impact
data for all the components, down to the finishes
and fitting out of each building. When such data
becomes more widely available, holistic LCAs
would increase the reliability of the evaluation
and ranking in general as well as the adequacy of
selected indicators. Further studies should always,
however, endeavor to keep the evaluation process
as simple as possible to ensure transparency and
understanding by all stakeholders.
Life-Cycle Analysis
Life-cycle analysis is a fundamental theory in envi-
ronmental evaluations. This paradigm recognizes
that a product has environmental impacts through-
out its entire life-cycle. Within the construction
industry, LCA is a method for the systematic
environmental assessment of a project from raw
material extraction through construction and use to
end-of-life management. This method has gained
prominence over the last decade, notably in its
application to commercial buildings (Guggemos,
2004; Junnila, 2003) as well as its inclusion in the
U.S. EPA TRACI framework (Bare et al., 2002).
The LEED green building rating system has faced
criticism over its emphasis on apparent environ-
mental benefit without an equal concern for the
durability of the products employed to achieve this
benefit. Humbert et al. (Humbert, Abeck, Bali, &
Horvath, 2007) performed a critical evaluation of
the LEED system using LCA and the U.S. Green
Building Council (USBGC) recently announced
the inclusion of LCA in future versions of LEED
(USGBC, 2007).
