They can last for a few hours up to weeks at a time. Also within this time frame after quitting, convulsions or seizures can occur, which is the point at which alcohol withdrawal can become dangerous if not medically treated. The symptoms may progress to delirium tremens (DT's) after three to five days without alcohol.
I would like to add that in US most of Instrument Ait pressure is 20-25 psi in the system and Plant (Service) Air pressure is 80-120 psi (about 7 atm). Both system require dryers, filters and some other equipment to do air conditioning.
But, the water that makes the air humid isn't liquid. It's water vapor, which is a gas that is lighter than nitrogen or oxygen. (Related: Understanding water in the atmosphere). Compared to the differences made by temperature and air pressure, humidity has a small effect on the air's density. But, humid air is lighter than dry air at the same temperature and pressure.