Healthier Indoor Air: Reducing harmful emissions from building materials and consumer products

All images courtesy National Research Council of Canada

By Hans Schleibinger, PhD, and Doyun Won, PhD
What could be more fundamental than the air we breathe? As it is invisible and a part of everyday life, people can sometimes take the quality of air for granted. Indoor air in Canadian buildings may contain hundreds of volatile organic compounds (VOCs)—a diverse group of chemicals emitted as a gas at room temperature that often reach higher concentrations than outdoors.

The known or suspected health effects of VOCs vary from one chemical to another, with adverse effects potentially including eye, nose, and throat irritation and respiratory symptoms. At higher concentrations, another potential long-term effect for certain VOCs may be cancer. Considering Canadians spend approximately 90 per cent of their time indoors, indoor air quality (IAQ) may significantly affect human health and well-being, according to the World Health Organization (WHO). (For more, check out 2010’s WHO Guidelines for Indoor Air Quality: Selected Pollutants, available at www.euro.who.int/__data/assets/pdf_file/0009/128169/e94535.pdf.)

To control the level of exposure in buildings to VOCs like formaldehyde, which was declared toxic under the 1999 Canadian Environmental Protection Act (CEPA) (more information is available through Health Canada’s 2006 publication, Residential Indoor Air Quality Guideline: Formaldehyde) and has been identified as a known human carcinogen by the U.S. National Toxicology Program (NTP) (this information was derived from National Toxicological Program’s 2016 Report on Carcinogens, Fourteenth Edition: Formaldehyde, from Research Triangle Park, NC, U.S. Department of Health and Human Services, and Public Health Service, available at ntp.niehs.nih.gov/go/roc14), there are two approaches: selecting low-emitting materials such as low-VOC paints, and diluting the concentration by increasing fresh air ventilation.

For a long time, source control has been recognized worldwide as a more effective and energy-efficient strategy for improving IAQ. (Read P.M. Bluyssen, E. De Oliviera Fernandes, L. Groes, G. Clausen, P.O. Fanger, O. Valbjørn, C.A. Bernhard, and C.A. Roulet’s 1996 report, “European Indoor Air Quality Audit Project in 56 Office Buildings,” in Indoor Air for more.) Since off-gassing from building materials and consumer products is considered the main contributor of most VOCs, labelling construction materials and products as ‘low-VOC-emitting’ is a very promising approach to this issue. A U.S. publication on indoor air quality requirements for green building certifications showed selecting low-emitting materials was already recommended in the majority of cases. (In this 2015 publication, Building and Environment, W. Wei, O. Ramalho, and C. Mandin discuss the topic of “Indoor Air Quality Requirements in Green Building Certifications.”) Material labels on VOC emissions will enable builders, retrofitters, facility managers, and homeowners to actively select low-emitting products and materials.

Figure 1: Range of formaldehyde emission factor for three categories of materials from four-day, small-scale chamber tests at the National Research Council of Canada (NRC).

Development of a Canadian emissions standard for building materials
There are currently a number of international labelling schemes to limit VOC emissions from building materials.  (For more on these labelling schemes, consult V.M. Brown, D.R. Crump, and P.T.C. Harrison’s 2013 article, “Assessing and Controlling Risks from the Emission of Organic Chemicals from Construction Products into Indoor Environments,” in Environmental Sciences: Processes and Impacts.) In Canada, the first health-based emissions standard was released in 2016 through the Canadian Standards Association (CSA) with financial support from Health Canada (HC). CSA O160-16, Formaldehyde Emissions Standard for Composite Wood Products, sets limits for the allowable levels of formaldehyde emissions from composite wood panels. The need for this standard was supported by observations that the eight-hour average indoor guideline for formaldehyde (50 mg/m3 [40 ppb]) was frequently exceeded in Canadian homes. (The observations are discussed in greater detail in P. Lajoie, D. Aubin, V. Gingras, P. Daigneault, F. Ducharme, D. Gauvin, D. Fugler, J.M. Leclerc, D. Won, M. Courteau, S. Gingras, M.È. Héroux, W. Yang, and H. Schleibinger’s “The IVAIRE Project – A Randomized Controlled Study of the Impact of Ventilation on Indoor Air Quality and the Respiratory Symptoms of Asthmatic Children in Single-family Homes” in a 2015 edition of Indoor Air.)

In collaboration with Health Canada’s Water and Air Quality Bureau, the National Research Council of Canada (NRC) did extensive work to identify the most relevant sources of formaldehyde indoors. For instance, the evaluation of 82 building materials for volatile organic compound emissions showed composite wood products are often the main sources of formaldehyde. This can be observed in Figure 1, which shows the amount in mg of formaldehyde emitted per surface area (m2) per time (h) for subsets of tested materials, including 15 composite wood materials, 11 paints, and 12 insulations.

CSA O160 was developed through a committee formed with representatives from Canadian stakeholders Health Canada, the Canada Housing Builders Association (CHBA), FPInnovations, the Composite Panel Association (CPA), the Canadian Wood Council (CWC), the Canadian Lung Association, numerous wood product manufacturers, NRC, and APA−the Engineered Wood Association. The standard is intended to harmonize with the existing, mandatory California Air Resources Board (CARB) Airborne Toxic Control Measure (ACTM) 93120, which will take effect as the U.S. Environmental Protection Agency’s (EPA’s) regulation on formaldehyde emission for composite wood products in 2018. (This information comes from the U.S. Environmental Protection Agency [EPA]. For more, visit www.epa.gov/formaldehyde/formaldehyde-emission-standards-composite-wood-products.)

The scope of CSA O160 and the U.S. standard is limited to hardwood plywood (HWPW), particleboard (PB), medium-density fibreboard (MDF), and thin MDF. Figure 2 lists maximum allowable chamber concentrations of formaldehyde for these material categories. (For more, consult Canadian Standards Association [CAN/CSA] O160-16, Formaldehyde Emissions Standard for Composite Wood Products.) How these chamber concentrations are typically measured will be described later in this article.

While CSA O160 is a voluntary standard, it is expected to serve as the basis for Canadian manufacturers to certify their low-emitting products. Since the development of CSA O160, a Notice of Intent (NOI) to develop a regulation targeting formaldehyde was published in Canada Gazette, Part I, on March 18, 2017. The NOI states that Health Canada and Environment and Climate Change Canada are initiating the development of proposed regulations to be made under CEPA seeking to reduce emissions of formaldehyde in composite wood products by regulating the manufacturing, use, processing, sale, offer for sale, and importation of these products into Canada.

Figure 2: The table above shows the limits for chamber-based formaldehyde concentration in air per Canadian Standards Association (CSA) O160, Formaldehyde Emissions Standard for Composite Wood Products.
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