Every time a toilet is flushed, tiny airborne droplets can spread beyond the bowl and land on nearby surfaces — a phenomenon known as a toilet plume. The question of whether to close the lid before flushing has a practical answer, but the full picture of bathroom hygiene is more nuanced than a single habit.
What happens when you flush with the lid up
The movement of water during flushing generates very small droplets that become airborne. These particles, collectively referred to as a toilet plume, can travel beyond the rim of the bowl and settle on surrounding surfaces.

