A characterization model with spatial and temporal resolution for life cycle impact assessment of photochemical precursors in the United States

Abstract

iv Photochemical pollution is formed due to the chemical reactions of atmospheric NO x , volatile organic compounds, CO, and CH 4 in the presence of sunlight. It is a complex, non-linear process influenced by several parameters which change spatially and temporally. Ozone, which is the most common photochemical, damages human health, ecosystems, and man-made materials. It also contributes to climate change. Traditional life cycle impact assessment methodologies have used aggregated impact factors for a country or even for a continent, neglecting these variations.This research assesses the geographical and temporal variability in the characterization factors for emissions of NO x and VOC over the continental US by developing monthly statelevel factors. A photochemical air quality modeling system (CAMx-MM5-SMOKE) is used to simulate the process of formation, transformation, transport, and removal of photochemical pollutants. Characterization factors are calculated at three levels along the cause-effect chain, namely, fate level, human and ecosystem exposure level, and human effect level.The results indicate that a spatial variability of one order of magnitude and a temporal variability of two orders of magnitude exist in both the fate level and human exposure and effect level characterization factors for NO x . The highest temporal variation in the characterization factors for NO x is seen in the Northeastern US. The summer time characterization factors for NO x are higher than the winter time factors. However, for anthropogenic VOC, the summer time describes LCA as "an objective process to evaluate the environmental burdens associated with a product, process, or activity by identifying and quantifying energy and material usage and environmental releases, to assess the impact of those energy and material uses and releases to the environment, and to evaluate and implement opportunities to effect environmental improvements. The assessment includes the entire life cycle of the product, process, or activity, encompassing extracting and processing raw materials; manufacturing, transportation, and distribution; use/re-use/maintenance; recycling; and final disposal." [Fava et al 1991] A LCA is divided into four phases as shown in Figure 1-1. The goal of an LCA identifies the intended application, the motivation, and its intended audience. The scope delineates the product systems or processes to be studied, the system boundaries, the environmental stressors considered, the data requirements, and all assumptions and limitations of the study. The Life Cycle Inventory (LCI) is the process of compilation of the material and energy inputs, and emissions to air, water, and land associated with the life cycle of the system. Life Cycle Impact Assessment (LCIA) assesses the environmental effects of the inputs and outputs of the system. In the Interpretation phase the results of the LCI and LCIA are combined, the goal and scope are reviewed, and the results of the LCA are evaluated to identify opportunities of system improveme...

Temporal differentiation of background systems in LCA: relevance of adding temporal information in LCI databases

“…First, the moment of the day or the season when the emissions occur is critical to certain impact categories. Seasonal variations are important in some contexts when assessing photochemical smog (Shah and Ries 2009), aquatic eutrophication (Hauschild et al 2002), water availability (UNEP 2011) or human toxicity (Manneh et al 2012), while diurnal variations are associated with ozone formation (Hauschild et al 2002) and the human health impact of noise (Cucurachi et al 2012). Annual variations in the background concentrations of environmental pollutants are also significant when considering the acidification impact category (Potting et al 1998).…”

A perspective on LCA application in site remediation services: Critical review of challenges

“…There is currently a trend towards making regional impact assessment models on acidification, eutrophication (aquatic and terrestrial), and photochemical oxidation, more site-dependent, providing pollutant characterization factors for other regions than Western European countries or the United States, or even for regions within these countries (e.g., [53][54][55][56][57][58][59]). …”

Implementing a Dynamic Life Cycle Assessment Methodology with a Case Study on Domestic Hot Water Production

“…). The production of photo‐oxidants from volatile organic compound (Graedel ; Shah and Ries ) and the effect of noise on human health (Cucurachi et al. ) also vary in time because they depend, respectively, on sunshine and resting periods.…”