Products used during construction and operation of a building can contribute to Indoor Air Quality (IAQ) problems that affect occupants' well-being. However, IAQ is conventionally not addressed in the life cycle assessments (LCAs) of buildings and building related products even though IAQ leads to one of the areas of protection under LCA - human health impacts. In this study, we proposed an overall framework for integrating IAQ into LCA using the standard steps of LCA. The framework focused on IAQ and LCA modeling from two categories of building related products: i) passive products that realize their function through initial installation and have long-term decayed emissions, and ii) active equipment that realize their function and cause emissions through daily operation. Dynamic and static life cycle inventory modeling approaches were proposed for passive products and active equipment, respectively. An indoor intake fraction equation and USEtox model effect factors were incorporated into the life cycle impact assessment. Three hypothetical examples were presented to illustrate the calculation procedure of the framework. We concluded that it was feasible to integrate IAQ into building related LCA studies. Development of IAQ related impact assessment methodologies can improve upon the limitations of this study. Further studies need to be carried out to compare the health impacts from IAQ related sources to other life cycle stages of building related products.
