Environmental health experts in the United States and Canada are hunting down dust bunnies, after studies have shown that the seemingly innocuous fluff may contain traces of threatening toxins.
According to a 2009 study from the University of Arizona published in Environmental Science & Technology, residents unwittingly track in outdoor contaminants, including lead and arsenic, which can settle into the layers of dust and recirculate in indoor air if disturbed.
The researchers derived a formula to calculate the amount of outdoor soil and airborne particles that intermixes with indoor dust.
Based on their mathematical model, they determined that around 60% of floor dust comes from soil stuck on shoes. And if someone lives near a contaminated site or industrial plant, that dirt could be loaded with toxins.
Gathering more data
"Although we've conducted a small pilot project to collect our own data to validate the model presented in this study, the next step would be to conduct a larger study where we'd collect data from several households," says Assistant Professor Paloma Beamer, an environmental scientist at the University of Arizona. "Ideally, we'd also like to see if participants could collect their own samples."
Obtaining baseline contaminant levels could eventually lead to low-cost measures for healthier household environments, particularly in polluted regions.
While Beamer says that residents in less commercially contaminated areas shouldn't be as worried about toxic dust, health officials in Canada are also sampling indoor dust from urban households across the country for various chemicals and metals.
"In addition to the outdoor sources listed in the University of Arizona study model, we've observed that indoor sources also contribute significantly to metal content of indoor dust," says Gary Holub, a spokesperson for Health Canada, which is conducting the Canadian House Dust Study, a separate, ongoing, four-year project. "But the relative contributions of outdoor and indoor sources are highly variable."
For instance, the first phase of the Canadian study found inconsistent amounts of lead in house dust, even among homes in the same neighbourhood.
Children most at risk
Although the exact dust contaminant threat remains unknown, Holub and Beamer each noted that children are more at risk because of their size and play activity.
"Indoor dust can be swallowed by young children through normal hand-to-mouth activities, and in that way, they can become exposed to any chemicals which are in the dust," says Holub.
The University of Arizona study also stated that the amount of lead particles in floor dust is a key determinant of blood-lead levels in children.
But there are many simple methods parents can take to prevent dust from settling inside, which will improve indoor air quality for all residents.
"You could consider leaving your shoes outside the door, and you can vacuum with a HEPA vacuum, especially ones equipped with a dirt detector," says Beamer. "You can wet dust rather than dry dust, and you should also change your air conditioning filters regularly."