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. (See the top 10 scientific discoveries of 2009.)

Layton and Beamer, whose latest study has been accepted for autumn 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. From Time.com.