Grandma Was Right: Sunshine Helps Kill Germs Indoors

University of Oregon scientists used real dust from inside homes around Portland to test the effects of sunlight, UV light and darkness on bacteria found in the dust.

All kinds of bacteria live with us indoors, and some can make us sick. A new study shows that rooms exposed to light had about half the live bacteria found in rooms that were kept in darkness.

(Image credit: Dave G Kelly/Getty Images)