If air is made up of 78% Nitrogen, our blood uses Oxygen and we exhale Carbon dioxide, what happens to nitrogen?

Question

If air is made up of 78% Nitrogen, our blood uses Oxygen and we exhale Carbon dioxide, what happens to nitrogen?

In: Biology

Answer 1

We don’t *just* exhale carbon dioxide. Basically, we inhale air, and we exhale air. What changes is the proportions of the gases in that air. The air we inhale has about 20% oxygen and less than 0.1% CO2. The air we exhale has about 16% oxygen and 4% CO2. The rest was, and is, nitrogen.