 Many common building materials emit hazardous pollutants over their lifespan, contributing to poor indoor air quality. Due to low air cycling rates in public buildings, it takes some time for these pollutants to be diluted by fresh air. New materials generally emit these contaminants to a greater extent than older materials, as the rate of off-gassing slows over the lifespan of the material (1).
Examples of pollutants emitted from building materials include asbestos and volatile organic compounds (VOCs) such as formaldehyde. While asbestos is known to cause cancer, and its carcinogenicity was suspected early in 20th century, it was commonly used in buildings as a fire-resistant insulation up until the 1980s. While its use is restricted in new buildings, it is still present in many old buildings. VOCs are a large group of chemicals that vaporize readily from a solid or liquid at room temperature. The presence of VOCs in indoor air is associated with a wide-range of physical symptoms, including eye, nose and throat irritation, headache, nausea, and damage to the liver, kidney and central nervous system (2). VOCs are emitted from buildings materials like paints, plywood, glues, wood preservatives and textiles. The VOC formaldehyde - a known carcinogen - is abundant in wood composite products (3).
In today's market there are many building products available which emit much lower levels of these pollutants, although few materials - other than glass and stainless steel - are completely emission free. A number of certification boards exist which will certify eco-friendly products based on multiple criteria, including pollutant off-gassing. The primary certification board in Canada is the EcoLogo Program, launched by the Government of Canada in 1988. Under this certification board, all approved building materials and fixtures must meet strict emissions limits for VOCs and must be free of chlorofluorocarbons.
Sources:
1 Light House Sustainable Building Centre, 2007. BC Green Building Code Background Research: Materials Emissions and Indoor Air Quality.
2 U.S. Environmental Protection Agency, 2009. An Introduction to Indoor Air Quality: Volatile Organic Compounds (webpage).
3 International Agency for Research on Cancer, 2006. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 88: Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol.
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