Many of the potentially harmful chemicals found in our homes linger on walls and other surfaces, suggests a new study out Wednesday. Unfortunately, ventilating rooms with fresh air or cleaning surfaces might not do much to reduce our exposure to these contaminants.
The new study, published in Science Advances, is part of a larger project involving researchers from several universities in the U.S. and Canada, intended to look at how environmental chemicals in the home are affected by everyday activities like cooking. It’s called the House Observations of Microbial and Environmental Chemistry (HOMEChem) study.
The research team wanted to find out what happens to these chemicals after people clean their floors or open a window. To do this, they set up a single-story test home where they could measure in real time the levels of 19 contaminants commonly found in indoor environments. These included isocyanic acid (often produced by cooking or smoking), nitrous acid, and many chemicals sent into the air from building materials and furniture.
Outdoors, many of these contaminants quickly turn into vapour in the air. But indoors, according to senior study author Jonathan Abbatt, a professor of chemistry at the University of Toronto, they often stick to the surfaces of a home, which act as “reservoirs.” These reservoirs then make it much more difficul to get rid of these chemicals.
“Our study showed that many of the molecules we breathe have large reservoirs on indoor surfaces that rapidly replenish the air after closing the windows,” Abbatt told Gizmodo via email. “Others have done similar work, but ours was the first with a wide suite of fast time response instrumentation in a genuine indoor building.”
The team also found evidence that other methods of cleaning, like mopping the floors with a vinegar solution, can actually increase the levels of some contaminants in the air, at least temporarily. Importantly, though, the findings aren’t proof that ventilation doesn’t work at all to lower our exposure to these chemicals.
“I wouldn’t say ventilation is fruitless or harmful. It may just be less effective than we think it may be,” Abbatt said.
The team cites research suggesting that heavy or chronic exposure to these contaminants can be harmful to our health. Isocyanic acid, for instance, may be one of the reasons why cigarette smoke is so dangerous to our heart and circulatory system, while too much indoor nitrous acid might worsen lung function. But the researchers are careful to point out their study wasn’t designed to reveal how dangerous these lingering chemicals could be to people.
“We’re measuring the chemicals and how these chemicals behave and move around in a variety of environments, but we’re not looking at their health effects,” lead author Chen Wang, a postdoctoral researcher at the University of Toronto at Abbatt’s lab, told Gizmodo. “There’s a lot of potential study on that too, but this isn’t our expertise.”
That said, better understanding of how these chemicals behave in our homes will hopefully make it easier to learn how we get exposed to them. If many contaminants are readily found on surfaces and not so much in the air, Chen noted, then we might need to be more worried about skin contact than breathing them in. Regardless, Abbatt said, there are ways to lessen our exposure to common sources of pollution in the home.
“In general, it is probably best to use fewer cleaning and air freshening agents,” he said.