Humans breathe in and exhale an average of 7 or 8 liters of air per minute.
That 7 or 8 liters of air translates to around 11,000 liters of per day that the average human breathes in per day which is quite a bit of air.
Without that air we would not live so air is a wonderful thing and we breathe in a lot of air without even realizing it or thinking about it.
The air that us humans inhale is around 20 percent oxygen and the air we exhale is around 15 percent oxygen.
We never really think about breathing in the air but it's something we do thousands of times per day and never really think about it but it's very important to our lives besides water and food.