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.
The two temperatures are different you are correct. Air temperatures are measured at about 4.5 feet and ground temperatures are taken at the ground. Typically when you plant the ground needs to be thawed out and you need to take the temperature either at the soil or slightly into it.