Most of the Dust in Your Living Room May Have Started Outside

We tend to think of dust as something a house makes by itself: skin, lint, fibers from the couch. Some of it is. But a much-cited 2009 study suggests the bigger share arrives from outside.

Researchers David Layton and Paloma Beamer built a computer model to follow soil and airborne particles as they move from the yard and the street into a home. Published in the journal Environmental Science & Technology, the model estimated that more than 60 percent of house dust starts outdoors. It gets in two ways: floating in on air through windows, doors and gaps, and riding in on the soles of shoes.

Two important caveats. This was a model, not a nationwide count of real dust bunnies, and it was applied to homes in the Midwest. Your house, climate and habits will change the mix. Still, it’s a useful reminder that the outdoors doesn’t stay outdoors.

That matters for more than housekeeping. The EPA points out that lead in soil can be tracked into homes on shoes and clothes and end up in household dust. The EPA’s advice is refreshingly simple: put doormats both outside and inside every entryway, take shoes off at the door, and wipe pets’ fur and paws after they’ve been out.

In other words, the most effective dust tool in your living room might be sitting by the front door.