It's forced air circulation. Fresh air is pumped in from the hallway usually, and small vents located near the ceilings allow the pressurized air to escape along with humidity.
I don't know the reason for it over a normal vent, but it does allow moisture to be pulled from a room without relying on the occupant to switch something on.
309
u/[deleted] 20d ago edited 15d ago
[deleted]