Here's why you should close the toilet lid before flushing

Researchers Aaron True (left) and Crimaldi stand in the lab where they studied the aerosols emanating from a flushed toilet. — Photos: University of Colorado Boulder/TNS

Engineers at the University of Colorado Boulder in the United States have confirmed what the germphobic among us have long suspected: The flush of a commercial toilet releases a Vesuvius-like cloud of tiny droplets and aerosol particles that reaches more than five feet (1.5m) above the seat.

Though invisible to the naked eye, when illuminated by green lasers, the plume appears like a burst of microscopic confetti thrown at the world’s grossest party – one composed of tiny drops of water and whatever else might be in the bowl.