How is carbon dioxide primarily transported in the bloodstream?

Carbon dioxide is primarily transported in the bloodstream in a dissolved form. While a small fraction directly dissolves in the plasma, the majority is carried in the blood as bicarbonate ions (HCO3−). This process involves the conversion of carbon dioxide and water into carbonic acid (H2CO3) through an enzyme called carbonic anhydrase. Carbonic acid then dissociates into bicarbonate ions and protons. The bicarbonate ions are transported in the plasma, and protons bind to hemoglobin. This efficient mechanism allows the blood to carry carbon dioxide from tissues to the lungs, where it can be expelled during respiration.