Water vapor is a colorless, odorless and transparent gas, and the white smoke you see is the same as the water liquefied when it is cold, giving the water vapor a color, and the whole is basically still gaseous, so it floats upward. The humidifier sprays liquid water.
Because the air coming out of the humidifier contains a lot of water vapor, which is denser than the surrounding (relatively dry) air, it sinks.
It may be that the low temperature in the room causes the fog particles to be difficult to vaporize into the air, and the humidification amount can be reduced to reduce the formation of large humidification particles. Wooden floors are prone to mold after moisture, and the water vapor on the floor should be wiped clean with a dry rag in time to prevent the board from being wet.