Life cycle assessment of wood-based boards produced in Japan and impact of formaldehyde emissions during the use stage

This study aims to conduct a comprehensive life cycle assessment (LCA) of wood-based boards to support environmentally conscious design. The goal is achieved by the following objectives: to produce generic LCA data for production of wood-based boards (cradle-to-gate) and to evaluate the human health impacts through life cycle including the use stage (cradle-to-grave), based on the latest regulations for formaldehyde emissions in Japan.

Production data of particleboard (PB), hard fiberboard (HB), medium-density fiberboard (MDF), and insulation fiberboard (IB) were obtained from major manufacturers of wood-based boards in Japan. We evaluated the impact categories of climate change, abiotic resource depletion, human toxicity (cancer and non-cancer effects), and ecotoxicity (cradle-to-grate assessment). For the human health impacts by formaldehyde emissions from PB and MDF in the use stage (40 years), we calculated the impacts through the life cycle (cradle-to-grave assessment), at all grades of formaldehyde emission rates set by the formaldehyde regulation.

Cradle-to-gate assessment indicated that adhesives constituted 28–55% of the impacts in all categories for PB and MDF, whereas 74–98% of the impacts resulted from utilities supply for HB and IB. In particular, heat supply from wood boilers accounted for more than 92% of human health (non-cancer) and 71% of ecotoxicity impacts in HB. Cradle-to-grave assessment of PB and MDF, which satisfy strict regulations on formaldehyde emissions (<0.005 mg/m²/h), demonstrated that impacts on human health (total of cancer and non-cancer effects) were decreased by more than 90% compared with a conventional product (0.15 mg/m²/h). The production stage impacts of the products meeting the string regulations were more than half of the total owing to the lower formaldehyde emissions in the use stage.

Generic LCA data for wood-based board production (cradle-to-gate) in Japan are calculated. Significant impacts are adhesives for PB and MDF and utility supply for HB and IB. The cradle-to-grave assessment of PB and MDF revealed that shifting to low-formaldehyde emission products has markedly reduced impacts on human health. We recommend preferentially improving the environmental performance of the production process of wood-based boards in countries with strict regulations on formaldehyde emissions.