It’s hard to get too worked up about dust. Yes, it’s a nuisance, but it’s hardly one that causes us much anxiety — and our language itself suggests as much. We call those clumps of the stuff under the bed dust bunnies after all, not, say, dust vermin.
But there’s a higher ick factor to dust than you might think. And there’s a science to how it gets around — a science that David Layton and Paloma Beamer, professors of environmental policy at the University of Arizona, are exploring.
Layton and Beamer, whose latest study has been accepted for fall publication in the journal Environmental Science & Technology, knew a lot about their subject even before they set to work. Historically, everyone from chemists to homemakers has tried to figure out just what dust is made of, and the Arizona researchers drew their preliminary data mostly from two studies of household dust conducted in the Netherlands and the U.S. The American survey in particular was a big one, covering six Midwestern states. Layton and Beamer also included a localized study in Sacramento, Calif., that focused particularly on lead contamination. What all those surveys showed was decidedly unappetizing.
The specific dust mix in any household differs according to climate, age of the house and the number of people who live in it — not to mention the occupants’ cooking, cleaning and smoking habits. But nearly everywhere, dust consists of some combination of shed bits of human skin, animal fur, decomposing insects, food debris, lint and organic fibers from clothes, bedding and other fabrics, tracked-in soil, soot, particulate matter from smoking and cooking, and, disturbingly, lead, arsenic and even DDT.
“There are more [components],” Beamer says. “Dust is a hodgepodge of all sorts of things. It would probably be impossible to make a list of all the possible items.”
But dust’s ingredient label is not the whole story, since all of those flecks and bits behave differently and present different levels of health risk. To investigate those factors more closely, Layton and Beamer developed a computer algorithm that looked at the size, source and toxicity of dust particles as well as how easily they enter the house, if they ever exit and, if so, by what route. That information, by extension, can provide at least a rough sense of the dust load in your own home.
