Is the volume of air breathed in the lungs equal to the volume breathed out the lungs?

Question

Is the volume of air breathed in the lungs equal to the volume breathed out the lungs?

Answer 1

No.  You exhale a slightly larger volume than you inhaled.

The "extra" comes from water vapor -- which you drank in liquid form, or was produced by metabolizing food.

Answer 2

On average, yes. Average meaning you measure all your breaths and all your exhalation over a long period of time etc...

Independently, no. Each breath and exhalation do not correspond in volume.

Answer 3

Actually there is a very slight difference in the volumes depending upon the diets of the subjects (are sugars or fats being metabolized) and the levels of activity.  The difference is relatively small even in an eight hour period.

Answer 4

Yes, if you measure it over a period of time of  5 minutes.