Inhaled air is by volume 78% nitrogen, 20.95% oxygen and small amounts of other gases including argon, carbon dioxide, neon, helium, and hydrogen. The gas exhaled is 4% to 5% by volume of carbon dioxide, about a 100 fold increase over the inhaled amount.,
The primary component of an exhaled breath has to be CO₂. The partial pressure of CO₂ at the tissue level is more than in blood therefore the CO₂ diffuses from tissue to blood at the tissue level.22-Sept-2021
The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out (called expiration, or exhalation). This exchange of oxygen and carbon dioxide is called respiration.