On average, Americans spend over 21 hours per day inside of buildings. The most vulnerable, infants and elderly, spend even more time indoors. For most Americans, exposure to toxic air pollutants is dominated by what we breathe indoors, rather than what we are exposed to outdoors. These health risks dwarf all other environmental exposures the typical person will be subjected to.
For that reason, reasonable changes in building design and operation must be made in order to improve indoor environmental quality. The social cost due to poor health is considerable. The economic cost in terms of worker productivity in the United States alone is estimated to be on the order of tens of billions of dollars annually. In fact, studies have shown that improved indoor air quality can raise worker productivity and even raise the test scores of school children.
A Shift to Indoor Air Quality Research
Despite knowing the importance of indoor air quality, the majority of research and funding today continues to be focused on outdoor air quality issues. There are more laws and regulations of products and processes that effect outdoor air quality than there are for indoor air quality. Research into the impacts of building materials, furniture, chemicals, and other products on human health are still relatively new but gaining serious attention in academic circles.
The Building Energy and Environments Program at the University of Texas in Austin is leading the way in indoor air quality research and is making significant and sometimes unexpected discoveries year in and year out. Led by Dr. Richard Corsi, the program and the University’s Indoor Air Quality Lab are paving the way to understanding what is in the indoor air we breathe and the impacts on our health and wellbeing.
Earlier this summer, we were treated by Dr. Corsi to a tour of the IAQ Lab on the J. J. Pickle Research Campus in Austin, Texas, where faculty and students conduct micro (small test chamber) and macro (full size home) laboratory testing of indoor air. The lab tour and presentation was one of the highlights of the 2017 Austin Sustainable Building Material Forum, a gathering of thought leaders in the manufacture, specification, and installation of building materials. What we learned on this brief tour was nothing short of surprising.
Are We Doing More Harm Than Good?
As the construction industry continues to push for the greenest and most sustainable building materials, indoor air quality has become significantly more important. The industry has successfully reduced or eliminate VOC’s (volatile organic compounds) from indoor materials and finishes in response to the known effects of these pollutants on human health. While the push to rid our building of VOC’s has been positive, there have been some unintended results.
When policies mandate change, we often don’t immediately recognize or realize the impacts. What the researchers at the IAQ Lab have discovered is that manufacturers of the glues and paints used in buildings have significantly reduced VOC’s, but are now using SVOC’s (semi-volatile organic compounds) in order to maintain the material’s effectiveness. While manufactures are able to claim “0% VOC content for their new “sustainable” products, SVOCs may not be any better in the long-run.
Semi-volatile organic compounds are a subgroup of VOC’s that tend to have a higher molecular weight and higher boiling point temperature than VOC’s. SVOC’s are of concern because of their abundance in the indoor environment and their potential for negative health effects on humans. SVOC’s are found in carpets, textiles, furniture, mattresses, paints, aerosols, personal hygiene products, cleaning products, and flame-retardants to name a few. The health effects from exposure to SVOC’s vary depending on the particular SVOC, the length of exposure, and personal sensitivity. SVOC’s have been associated with allergies, asthma, endocrine and thyroid disruption, reproductive toxicity, and fetal and child development delays.
How Heat and Humidity Makes Things Worse
Another interesting research topic being studied at the IAQ Lab is the effects of relative humidity (RH) and temperature on chemicals stored in the surfaces of materials inside buildings. Chemicals we bring indoors with us, cleaning products and household items we use every day, and building materials like carpet glue, paint, and numerous other products are all sources of potentially toxic pollutants. The lab discovered that as indoor humidity increased in a building, the water molecules in the air are adsorbed (adhesion of molecules of gas, liquid, or dissolved solids to a surface) onto the various materials in the building, thereby displacing chemicals already adsorbed to the material and releasing them into the air. They also found that as the temperature in a building rose, there was an increased rate of release of chemicals into the air.
The tour was eye opening and led to many questions for Dr. Corsi and the researchers at the IAQ Lab. As buildings are being bombarded with higher heat and humidity in the summer what is being released into the indoor air we breathe? As the architecture and construction industries continue to push for more sustainable building practices, we need to be more knowledgeable of the drivers of indoor air quality for the buildings we are designing and constructing.
Improving Indoor Air Quality
For starters, designers should be specifying materials with no VOC’s and no SVOC’s. Using fewer adsorptive materials will help reduce the trapping and storage of potentially dangerous chemicals and pollutants that can contribute to long term health effects. A thermally efficient wall system with a high performing air barrier and well-designed HVAC system can also help by keeping the humidity and temperature well-regulated, keeping outdoor pollutants out, and effectively filtering indoor pollutants before they cause problems.
Buildings need to be built better with a specific focus on the indoor air quality for the occupants. The Bautex Wall System™ gives architects a thermally efficient and air tight building envelope option for commercial and residential construction. Bautex Interior Wall Finish (IWF) is a direct-applied abuse-resistant plaster that can be applied to the Bautex Wall System as well as conventionally framed interior walls. The IWF finish provides a 0%VOC and 0%SVOC hardened surface that provides a healthier, stronger, and easier to maintain finish compared to conventional drywall and paint.
For more information about indoor air quality and the Bautex Wall System, visit bautexsystems.com