Geographically Differentiated Life-cycle Impact Assessment of Human Health
- Author(s): Humbert, Sebastien
- Advisor(s): Horvath, Arpad
- et al.
In this dissertation, I explore how life-cycle assessment (LCA) results can potentially be influenced by the location of emissions, also called regionalization. The current practice in life-cycle assessment increasingly stresses the importance of being "geographically differentiated" or "regionalized." Regionalization can be important for cases that have extended supply chains distributed across different regions or for processes situated in locations with environmental conditions and population densities far from "average". A spatially resolved model for North America, called IMPACT North America, is developed here. Geographically differentiated intake fractions and characterization factors are evaluated for the North American continent for human toxicity. Special attention is given to the modeling of intake fractions and characterization factors for particulate matter. These factors can be used to adapt damage-oriented impact assessment methods. Parameters influencing intake fractions and characterization factors are identified, such as population densities and agricultural production. The importance of modeling an "urban box" and a "remote area" is also shown. The case of fly ash concrete is studied through the lens of regionalization, and critical parameters influencing the environmental trade-offs between fly ash concrete and Portland cement concrete are identified.
Through the development of the new model, along with the different applications, various questions related to spatial life-cycle assessment can be studied, and several conclusions can be drawn about what is important to consider when performing regionalization in life-cycle assessment.
I show that particulate matter dominates damage to human health and therefore the importance of devoting more detailed attention to the character of particulate matter when modeling the fate, exposure and effect of pollutants. I also demonstrate that when addressing the issue of regionalization in inventory and impact assessment, priority should be placed on the development of the archetype-based (i.e., situation-dependent) regionalization; spatialization (geography-based regionalization) should only be used secondarily and in occasional cases when results from key processes need to be expanded.