Indoor environmental quality in a dynamic life cycle assessment framework for whole buildings: Focus on human health chemical impacts

A framework was developed for integrating indoor environmental quality (IEQ) into life cycle assessment (LCA). The framework includes three main impact types: 1) chemical-specific impacts directly comparable to conventional life cycle impact assessment (LCIA) human health categories, 2) non-chemical health impacts, and 3) productivity/performance impacts. The first part of the framework related to contaminant specific impacts was explored using a green university building as a case study, while the remaining categories will be the subject of future work. Results showed that including IEQ aspects in whole-building LCA revealed LCIA internal impacts in some categories comparable to external impacts. For human health respiratory effects, building-specific indoor impacts from the case study were 12% of global external impacts in conventional LCA. Building-specific indoor cancer toxicity impacts were greater than external impacts by an order of magnitude, and building-specific indoor noncancer toxicity impacts were lower than external impacts by an order of magnitude. Although internal impacts were greater than external impacts in one category - cancer toxicity, the source of the contamination in the other two categories - respiratory effects and noncancer toxicity - was related to intake of outdoor air. The findings of this study underscore the importance of filtration or other treatment of mechanically supplied outdoor or recirculated indoor air, as well as control of pollution from indoor sources such as building materials or cleaning products. These findings may support the use of green building rating systems which include acknowledgment of the aforementioned IEQ-related features.