I have a person (average adult male, ~180lbs/80kg) locked in a completely sealed room.
The room is 10 by 10 by 10 feet (one thousand cubic feet, 28.3 cubic meters) and at the time of sealing, was filled with typical fresh air.
Assuming he stays calm... How long would the air last?
How would size/age of people affect that rate? I don't need precision, but just rough numbers like "A ten year old would only use 0.6 times as much air" or whatever.