ubic foot) of air per minute. That totals something like 11,000 liters of air (388 cubic feet) in a day. Imagine a 7'-0" x 7'-0' x 7'-0" cube = 343 cu ft. • The air that is inhaled is about 20-percent oxygen, and the air that is exhaled is about 15-percent oxygen, so about 5-percent of the volume of a