Including indoor offgassed emissions in the life cycle inventories of wood products.

Volatile organic compounds (VOCs) that negatively affect human health are emitted from wood products used indoors. However, the existing life cycle inventories of these products only document the emissions occurring during production and disposal phases. Consequently, the life cycle assessment (LCA) of indoor wooden products conducted using these inventories neglect the use-phase impacts from exposure to offgassed VOCs and therefore underestimate the product's total environmental impact. This study demonstrates a methodology to calculate the use phase inventory and the corresponding human health impacts resulting from indoor use of any VOC emitting product. For the five most commonly used types of boards used in indoor wood products, the mass of each VOC emitted into the indoor compartment over their service life was calculated by statistically analyzing data from 50 published chamber testing studies. Uncertainty was assessed using Monte Carlo simulations. The calculated inventory data were used in a case study to calculate and compare the health impacts of five different wooden floorings made of above materials. The results show that the use-phase human-toxicity impacts are an order of magnitude higher than those occurring during the rest of the flooring's life cycle. The factors influencing the offgassing of VOCs from wood products and measures to reduce exposure are discussed.