Breath of Life

During an average lifetime, 13 million cubic feet of air passes through our lungs enough to fill a football stadium. The oxygen within the air provides us with energy, as it reacts with sugar within our cells, but it is a tortuous journey for the oxygen to make. First, the air is moistened in the nose to filter out pollutants. It is passed down to the lungs, through air passages that split over and over again, ending up in 700 million tiny air sacs. Here, oxygen passes into the blood, while the waste product, carbon dioxide moves from the blood into the lungs, to be breathed out.