Page 85 - Materials Chemistry, Second Edition

4

Life Cycle Impact Assessment

1
Manuele Margni and Mary Ann Curran 2
1
CIRAIG, Montreal, Canada
2
US Environmental Protection Agency,
Cincinnati, OH, USA*

Abstract
The overarching purpose of life cycle impact assessment (LCIA) is to pro-
vide additional information to assess life cycle inventory (LCI) results and help
users better understand the environmental significance of natural resource use
and environmental releases. An important distinction exists between LCIA and
other types of impact analysis, such as traditional risk assessment: LCIA does
not directly assess the impact of chemical releases. This chapter presents a brief
history of the development of the state-of-the-art LCIA approach, and describes
the diversity that is found in the various LCIA models that are currently used,
along with the accompanying criticism that comes from having several choices of
methodologies. The chapter concludes with a discussion on the direction of future
LCIA development. Most significantly, further development is needed in model-
ing important resource-related impact categories, such as water use and land use,
addressing issues such as ecosystem services, and incorporating spatial and tempo-
ral differentiation.

Keywords: Life cycle assessment, life cycle impact assessment, indicator, midpoint,
endpoint, area of protection

4.1 Introduction

A well done life cycle inventory consists of a large quantity of data about natu-
ral resource use and releases to the environment. However, at this point in the
assessment, these data are difficult to interpret. It is impossible to decide what
the environmental impacts of a system are by considering only the mass that
is extracted or released. Obviously, one pound (or kilogram) of one type of air
emission or waterborne pollutant can have a vastly different impact on human

* The views expressed in this chapter are those of the authors and do not necessarily reflect the views or
policies of the US Environmental Protection Agency.

Mary Ann Curran (ed.) Life Cycle Assessment Handbook: A Guide for Environmentally
Sustainable Products, (67-104) © 2012 Scrivener Publishing LLC
67