Integrating Occupational Health into Life Cycle Assessment Open Access
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Life cycle assessment (LCA) is a systems-based method used to determine potential impacts to human health and the environment associated with a product throughout its life cycle. Conclusions from LCA studies can be applied to support decisions regarding product design or public policy, therefore, all relevant inputs (e.g., raw materials, energy) and outputs (e.g., emissions, waste) to the product system should be evaluated to estimate impacts. However, work-related impacts to human health are not considered in LCA. Integrating occupational health into LCA will provide opportunities to prevent shifting of impacts between the work environment and the environment external to the workplace. Three separate efforts are made in this dissertation research. First, we introduce the work environment disability-adjusted life year (WE-DALY), one portion of a characterization factor used to express the magnitude of impacts to human health from the work environment. The concept of the WE-DALY and the methodology for its calculation is grounded in the World Health Organization's disability-adjusted life year (DALY). Like the DALY, the WE-DALY equation considers the years of life lost due to premature mortality and the years of life lived with disability to estimate the total number of years of healthy life lost in a population. The WE-DALY equation considers the number of fatal and nonfatal injuries and illnesses that occur in the industries relevant to the product system evaluated in the LCA study, the age of the worker at the time of the fatal or nonfatal injury or illness, the severity of the injury or illness, and the duration of time lived with these outcomes. Second, we present a methodological approach for integrating occupational health aspects in LCA including steps to develop work environment characterization factors (WE-CF) and ways to structure life cycle inventory data to successfully employ the WE-CFs. The WE-CF is an index based on the ratio of WE-DALY to the physical quantity of goods produced in an industry; it is used to express the magnitude of impacts to human health attributable to workplace hazards. Third, the WE-CF is demonstrated in a work environment characterization model built within an existing LCA model. Specifically, the new characterization model is applied to update LCAs of landfill and waste-to-energy (WTE) municipal solid waste (MSW) management methods. In this application, human health impacts from environmental emissions and human health impacts from work environment hazards are assessed concurrently: WE-CF are used for work environment assessment and existing characterization factors are used for the environmental assessment. To gauge success of the work environment characterization model, we the usefulness of the impact assessment results to: 1) make comparisons of human health impacts between product systems; 2) make comparisons between human health impacts from work environment aspects and human health impacts from environmental aspects; and 3) identify work-related processes contributing to human health impacts and the portion of these impacts attributable to the processes.