Our lungs fuel the body with oxygen, the body's life-sustaining gas. They breathe in air, then extract the oxygen and pass it into the bloodstream, it's then rushed off to the tissues and organs that require oxygen to function. Oxygen drives the process of respiration, which provides our cells with energy. The waste gas carbon dioxide is produced as a byproduct and disposed of when we exhale. The Lungs breathe in between 2,100 and 2,400 gallons (8,000 and 9,000 liters) of air each day!