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Humans spend about 90 percent of our lives inside, so it鈥檚 time we analyzed what we鈥檙e breathing while we鈥檙e there.
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鈥淭here has been a huge gap between the research done indoors and out,鈥� said Marina Vance, a professor in the mechanical engineering department. 鈥淲hen you think of the news and studies on air quality, people are always studying the outdoors.鈥�
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Vance spent June leading the largest collaborative study to date on indoor air quality at a research house at the University of Texas, Austin research campus. She called it HOMEChem.
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鈥淢ost of the studies done on indoor air quality have been on occupational safety and comfort, measuring for individual compounds known to be detrimental to human health,鈥� she said. 鈥淢eanwhile, outdoor studies look at the air鈥檚 chemistry and interactions. We wanted to learn from that and bring a more holistic approach to studying indoor air quality.鈥�
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The Sloan Foundation funded the study as part of an initiative to understand the chemical processes happening in indoor environments. Working with Delphine Farmer, a professor of chemistry at Colorado State University, Vance developed a collaboration that would incorporate Farmer鈥檚 goal of data-sharing on the topic and Vance鈥檚 goal of community- building. The collaboration ended up with 20 faculty members from 13 universities.
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鈥淚n order to not focus on individual compounds, we had to measure many things at once,鈥� Vance said.
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While some studies are done with offline samples, like a cup of water taken from a river that gives a snapshot of the river at that specific point in time, the HOMEChem study was online, with measurements taken in real-time without pause. The researchers outfitted the house, a pre- manufactured 1,200-square-foot home with three bedrooms and two bathrooms, with varying instrumentation. With some windows converted to sampling ports and holes drilled in the walls for cables and tubing, the team led sampling lines to the house from four trailers full of instruments.听
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Vance and her team performed activities representative of those people do in their homes, like cooking, cleaning and occupying. The latter included the use of personal care products, many of which they found put out unhealthy compounds.
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鈥淭here are so many preconceived notions of what a clean home is,鈥� Vance said. 鈥淚 love that quote, 鈥楾hat smells fresh.鈥� You put an air freshener in the wall that smells like flowers, and you鈥檙e putting air pollution in your house. The same is true for scented candles and perfumes.鈥�
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Of the three kinds of cleaners they used, the chlorine-based was the most problematic.
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鈥淐hlorine is very reactive,鈥� Vance said. 鈥淭he chemical compounds it released created new compounds, including chloramines which can cause respiratory irritation.鈥�
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For cooking, the team mimicked typical days and also atypical ones. The team had Thanksgiving, in June, in Texas, twice.
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鈥淚 went to see a man about a turkey,鈥� Vance said about the dinners. 鈥淚t鈥檚 surprisingly difficult to find a whole raw turkey in June.鈥�
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Four volunteers cooked a Thanksgiving dinner before twelve guests arrived and ate the meal with the windows and doors closed, as on Thanksgiving it is often cold and the emissions are withheld.听
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鈥淲e had a very delicious, complete Thanksgiving meal,鈥� Vance said. 鈥淎nd we had very unhealthy levels of air pollution inside the house, the highest we measured during the study.鈥�
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Did it scare those present?
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鈥淚t did,鈥� Vance said. 鈥淏ut we were expecting it. And we鈥檙e all scientists, so we were actually happy. It鈥檚 crazy the things we鈥檒l do in the name of science.鈥�
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The emissions came mostly from roasting the turkey and vegetables in the oven.听
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鈥淚t鈥檚 really the temperature,鈥� Vance said. 鈥淚t didn鈥檛 matter so much what we cooked as how hot we cooked it. The key recommendation is: Use your range hood every time you cook. If you have a gas stove, use it even if you鈥檙e just boiling water.鈥�
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The scariest part of the study, in Vance鈥檚 opinion, was the observation of semivolatile organic compounds, or SVOCs. These sit on surfaces until disturbed and then they take to the air, latching onto dust and finding their way into our lungs. One example of an SVOC is the plasticizer on vinyl flooring.听
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鈥淩esearch is finally getting to the point of analyzing SVOCs in real time, which are very important to human health,鈥� Vance said. 鈥淒ust particles can act as a Trojan horse because they can travel deep into your lungs and release those SVOCs there.鈥�
Vance emphasized that HOMEChem is at the start of indoor air chemistry field studies, with many more necessary to discover how to optimize our health within our homes. 鈥淭his has been the most comprehensive indoor air chemistry study in a home environment,鈥� she said. 鈥淏ut we cannot answer every question, no way. We鈥檙e just discovering new ones.鈥�