And they breathe in the particles that have settled on their parents' clothes. This certainly puts snuggling up close to your children in a new light.
So what can be done?
Intrusive as it might sound, many experts are arguing for laws that would ban smoking in homes, just as laws have banned the use of lead paint indoors. Such laws can have an effect in protecting children.
But the effect is going to be largest when more and more people become aware of the hidden danger of third-hand smoke.
I have always told parents who smoke that tobacco smoke clings to their clothing and home furnishings -- and have usually received a blank stare back, like, "Are you from Mars, Dr. Spangler?"
Maybe now the stare will be one of recognition of the harm to which they are exposing their children.
At least, that's my hope.
We can thank these researchers for introducing this topic into the public discourse and for giving us a new name to think about -- third-hand smoke dust that is smokeless but not harmless.
Dr. John Spangler is director of tobacco intervention programs and a professor of family medicine at Wake Forest University School of Medicine in North Carolina.