The body binds free-floating carbon generated during energy metabolism through the bicarbonate system for exhalation as carbon dioxide.

“The only way that you're going to go through this process is if your body says do we have an oxygen molecule available that we can bind this to immediately? Yes we do. That carbon attaches to that oxygen molecule. You can't just put CO2 in the blood because of what we just talked about. So you're going to bind it through this bicarbonate process. It's going to go through your blood. It's going to go into the lungs. It's going to go back into its carbon dioxide molecule. It's going to trans, go through the alveoli into the lungs and you're going to exhale.”