This same principle applies to atmospheric composition. As seen in Table 1.1, each gas exerts its own partial pressure, and when combined, they make up the total barometric or atmospheric pressure. It is important to consider oxygen in terms of partial pressure versus percentage. The amount of gas that will dissolve into a liquid is dependent upon the partial pressure of the gas as well as the solubility. Henry's law brings with it the understanding of gas transfer between the alveoli and the blood.
Gases move from an area of higher concentration, to that of a lower concentration.
Decompression sickness is a direct result of the principles described in Henry's law in that as the partial pressure of the gas surrounding the body decreases, less gas will be held in the various body fluids. A bottle of carbonated soda is a good example of this principle. With the cap on the bottle, the gas above and within the liquid are in a state of equilibrium. When the cap is removed, gas pressure above the liquid decreases allowing gas within the liquid to be released in an effort to equalize the pressure above the liquid, which causes the formation of bubbles. An example of this law is that carbon dioxide is nineteen times more diffusible than oxygen due to its solubility factor.