Awesome @rosy_b thanks for the gouge! ・・・ Airbus Disco 🌐💃🏻
We get asked about this a lot! The mysterious fog coming from the air conditioner is just that, condensation. It happens often due to humid temperatures outside the airplane with cooler air in the cabin.
The air close to the outlets for the air conditioning is very cold and cools the cabin air it's meeting quickly down to that air's dew point. That cooled air warms back up as it continues into the cabin and this is why you see the vapor disappear: the air has warmed back above the dew point.