The flecks of dust visible in your sunlit window may not just inflame your allergies, they could also be hazardous to your health, according to a new study.
A survey of 26 peer-reviewed studies spanning households in 14 states revealed the presence of potentially toxic chemicals in 90% of dust samples, including phthalates used in plastics, environmental phenols like PBA, flame retardants, fragrances, and stain resistant compounds like those found on some carpets. Researchers found high levels of the compounds, but caution that they don’t know if those levels are high enough to cause harm.
About two-thirds of dust is composed of particles that come in from the outdoors—on our shoes, for example, or through an open door—while the other third comes from sources inside our homes—mostly things like carpet fibers but also skin flakes and pet dander.
The majority of chemicals reported in the 26 studies pose a hazard to human health. But we don’t know yet if the chemicals are present in dust in concentrations that would cause problems. Here’s Beth Skwarecki, reporting for Scientific American:
An important limitation of the study is that it only looked at the types and amounts of chemicals present in dust—not the health of people who spent time in places where the dust was collected. For many of the chemicals, we don’t yet know what amount should be considered hazardous for long-term exposure, [senior author Ami] Zota says. And we don’t know whether some of the chemicals might be more harmful in combination than they are individually.
Of the long list of compounds the study covered, the top two in terms of concentration—di-2-ethylhexyl phthalate and butyl benzyl phthalate—are both plasticizers. Plasticizers are used widely in plastics (no surprise) to increase their flexibility and durability. Zota and her colleagues estimate that those two compounds along with two other phthalates and a fire retardant are the most likely to be ingested by people. In sufficient concentrations, these chemicals can act as carcinogens, endocrine disruptors, or reproductive toxins.
Children, in particular, may be more exposed to these chemicals because they often play on the floor and frequently put their hands in their mouths. “Characterizing exposures from indoor dust may have important implications for children’s health,” the authors wrote.