Study: 'Green' Products Can Still Create IAQ Problems
In a recently completed study funded by GREENGUARD Environmental Institute (GEI), there was preliminary evidence that "green" low-emitting products may still cause increased chemicals in indoor environments.
The study, conducted by Chi Phuong Hoang, a doctoral candidate at the University of Texas at Austin's Civil, Architectural and Environmental Engineering program, revealed that even "green" wall, flooring, ceiling and cabinetry materials can cause "secondary" emission of chemicals when exposed to naturally occurring ozone in the indoor air.
Many green materials are bio-based and, as a consequence, may react even with low levels of ozone that naturally occur in the air, the researcher stated. After examining 10 such bio-based materials, Chi found that while the materials did not themselves emit volatile organic compounds (VOCs) into the indoor air, they reacted with ozone to create "secondary" emissions of VOCs. The three products that were found to emit the most secondary emissions were green ceiling tiles, natural cork wallpaper and wheat board.
Secondary emissions of VOCs may still harm human health. Other examples of secondary emissions is when porous materials, such as upholstery, carpeting and ceiling tiles, absorb primary emissions from high emitting building products and materials, and re-emit them into the indoor air. This is often referred to as the "VOC sink effect." To help avoid this problem, its good practice to apply wet products (paints, adhesives, coatings) before installing porous materials.
"The research confirms the importance of analyzing the impact that building products and materials may have on indoor air," said Carl Smith, GEI's CEO. "The interactions of the chemicals produced by products requires additional research into their reactions and impacts on human health and the environment."
Indirectly, the study reveals limitations of current measures of "green" products. Indoor air is a complex mix of chemicals, allergens and particles that react in ways that could potentially harm human health. While measuring the primary chemical emissions from products begins to address some of these issues, it still does not adequately predict all of the chemicals that might be present in indoor environments.