Even before Florence Nightingale advised that hospitals be designed to let daylight in, people observed that sunshine helps keep you healthy. But there was not much research to explain why that’s the case, especially inside buildings.

Researchers at the University of Oregon set up a study of dusty, dollhouse-size rooms to compare what happens in rooms exposed to daylight through regular glass, rooms exposed to only ultraviolet light and those kept dark. They used a mix of dust collected from actual homes in the Portland area and let the miniature rooms sit outdoors while keeping the insides at a normal room temperature.

After 90 days (because that’s how long dust can hang around, even if you vacuumed), they sampled the dust and…[Read More]