If it is quite warm and wet in the room, then when you open the vents in winter fog clubs are formed, which descend in the room, and go up on the street. Please explain the phenomenon.
White clouds of mist, when opening the window, are tiny droplets of water. In a warm room a large amount of steam accumulates. When opening the window, the air in the room cools, the steam begins to turn into tiny water droplets, forming fog. The temperature of the steam is lower than the air in the room, that is why the steam descends, but higher than the air in the street that is why on the street it rises.