When we breathe we inhale and exhale air. Exhaled air is warmer and cleaner than inhaled air.We inhale 78% Nitrogen and exhale 78% nitrogen. The percentage of Nitrogen does not change because the body does not use nitrogen.The percentage of Oxygen in exhaled air is less than in inhaled air because the body uses Oxygen for respiration. The percentage of carbon dioxide increases when exhaling as it is a product of respiration. Water Vapour The amount of water vapour in inhaled air depends on where you are but you exhale more water vapour because this is produced in respiration.
Hope it helps!!!