About 20-25 per cent of carbon dioxide is carried as

About 20-25 per cent of CO₂ is carried by haemoglobin as carbamino-haemoglobin This binding is related to the partial pressure of CO₂. pO₂ is a major factor which could affect this binding. When pCO₂ is high and pO₂ is low as in the tissues, more binding of carbon dioxide occurs whereas, when the pCO₂ is low and pO₂ is high as in the alveoli, dissociation of CO₂ from carbamino-haemoglobin takes place.