Enter the micro-chamber
To overcome the challenges of measuring SVOCs, micro-chambers (Figure 6) are often used as the more appropriate test environment, as opposed to small- or full-scale chambers. These micro-chambers are well-suited for measuring SVOCs because of their relatively high SVOC concentration levels, as a result of relatively large specimen surface area compared to the micro-chamber surface area. Emissions can also be accelerated with high chamber flow rates, making the chamber concentrations level off quickly. Testing speed benefits further from high operating temperatures and, since all the ‘exhaust air’ from the chamber goes through the sampling tube, this method leads to high analytical sensitivity—all while ensuring shorter testing times and lower costs.
In 2012, NRC developed a fast screening method using micro-scale chambers to determine phthalate emissions from building materials. (More on this method can be found in D. Won, E. Lustztyk, G. Nong, and H. Schleibinger’s 2012 Client Report: Materials Emissions Testing for Phthalates.) A total of 101 household materials, including 75 building materials and 26 consumer products, were tested using the method to identify the sources of 23 phthalates. Of these 23 sources, 19 have been prioritized for risk assessment in the second phase of the Chemicals Management Plan (CMP) by Health Canada. DEHP was one of the most frequently detected phthalates in these materials. The highest emission factors, though, were associated with diisononyl phthalate (DINP) in household products such as vinyl flooring, wallcoverings, and wires. The results also showed DEHP, which is on the List of Toxic Substances under CEPA, is in the process of being substituted by DINP in certain product categories. The results demonstrate the usefulness of the micro-scale chamber method for identifying the main sources of health-relevant phthalates, which are otherwise not easily detected or measured reliably with small- and full-scale chambers.
Conclusion
With the development of new building technologies and the movement toward the conception of greener buildings including all aspects from design through to the construction phase, it is important to have testing methods, facilities, and experts that can evolve with the times. There is a growing global demand for materials and products with low VOC emissions. For instance, Leadership in Energy and Environmental Design (LEED) certification takes into account air quality and has provisions for formaldehyde and various VOCs.
Canada is certainly no exception to this trend, as a recent release of the voluntary standard CSA O160 and an NOI by Health Canada to develop a regulation to reduce emissions of formaldehyde from composite wood products seem to be pushing the industry more actively in the low-VOC direction. While the health-based requirements for low-emitting materials in Canada are mainly focused on formaldehyde, more indoor chemicals in the VOC and SVOC categories may be expected to be the subject of Canadian labelling systems as more information on their toxicity to humans becomes available, and their exposure limits are more commonly considered.
NRC continues to put its resources and efforts toward developing test methods and solutions to support stakeholders with identifying and minimizing harmful chemicals at their sources, and to benefit manufacturers in developing low-emission products, as well as aiding building authorities in establishing feasible and meaningful criteria for material emissions guidelines and standards. There is always more work to be done, and NRC will continue working with partners in ensuring we are ready for tomorrow’s buildings. (The authors wish to acknowledge contributions in the areas of the health relevance of volatile organic compounds [VOC]) and semi-volatile organic compounds [SVOCs], as well as guidelines and regulations, from members of Health Canada’s Water and Air Quality Bureau and its Healthy Environments and Consumer Safety Branch—specifically, Patrick Goegan, Michelle Deveau, Katherine Guindon-Kezis, Lynn Bernd-Weiss, and Lara Kouri.)
Hans Schleibinger, PhD, is an environmental engineer who worked in the areas of air and water pollution control, prevention of mould growth, hospital hygiene, toxicology, and environmental analysis in Germany. He has headed the Ventilation and Indoor Air Quality Group of the National Research Council (NRC) since 2005, evaluating products and technological solutions and creating evidence-based knowledge for Canadian stakeholders. Schleibinger was one of the founders of the Canadian Committee on Indoor Air Quality and Buildings (CCIAQB). He can be reached at hans.schleibinger@nrc-cnrc.gc.ca.
Doyun Won, PhD, is a senior research officer at NRC, working on indoor air quality (IAQ) and ventilation. She has 19 years of experience in testing building materials and consumer products for chemical emissions, predicting their impacts on IAQ, and developing IAQ mitigation strategies. A member of the technical committee for Canadian Standards Association (CSA) O160-16, she currently serves as an associate editor for Indoor and Built Environment journal. She can be reached via e-mail at doyun.won@nrc-cnrc.gc.ca.
The authors would like to acknowledge the important contributions by Wenping Yang, Gang Nong and Stephanie So in NRC’s laboratories.
