Inhaled and exhaled air

Inhaled air contains:

  • more oxygen used to create energy
  • less carbon dioxide than…

Exhaled air which contains:

  • more carbon dioxide produced as a waste product of energy production
  • less oxygen as it has been used in respiration

Gas exchange takes place by diffusion in the alveoli within the lungs. As a result the composition of inhaled and exhaled air is different.

Percentage of gas present in inhaled and exhaled air:
Gas% in inhaled air% in exhaled air
Oxygen2116
Carbon dioxide0.044
Nitrogen7979
NB These figures are approximate.
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