The average adult at rest inhales and exhales something like 7 or 8 liters (about one-fourth of a cubic foot) of air per minute. That totals something like 11,000 liters of air (388 cubic feet) in a day. 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 air is consumed in each breath and converted to carbon dioxide. Therefore, a human being uses about 550 liters of pure oxygen (19 cubic feet) per day. A person who is exercising obviously uses a lot more oxygen than that. You could determine how much air is moving through your lungs by exhaling into a plastic bag of known volume at each breath and seeing how long it takes to fill the bag. http://72.14.209.
On average, people take about 24,000 breaths per day, for a total of 3,000 gallons. But, that is meaningless in the context of an individual. Even if we assume that the rate at which people take their breaths to be constant for all people, there would still be variations due to the difference in size of a persons’ lungs. However, we know that the rate at which people breathe is not constant throughout the day. It varies depending on what we are doing. All this is intended to say, that an average of how much air people in general breathe per day is not an indicator of how much air an individual would breathe in the same time period. If you need to know about a specific individual, you may want to follow the guidelines laid out in this experiment. http://chemistry.bd.psu.