This means that the number of molecules in the total volume of a gas is proportional to the number of molecules in each gas composition. Thus, while increasing the total gas pressure as a diver enters the water, the partial pressure of each of them also participate increases, and the consequences that could cause divers body also increases. For example, the air is a mixture of gases that approximately 80% of the nitrogen and 20% oxygen, although small amounts of other gases including. Dalton's law, partial pressure of nitrogen and oxygen to the air will equal the total air pressure, and simultaneously increase. A case in which the effects determined by Dalton's law should be seriously considered by divers in nitrogen. When increasing the partial pressure of nitrogen would lead to greater concentration of dissolved nitrogen in the blood of divers, and this can lead to suffer nitrogen narcosis. This, among many other situations that may arise from the facts mentioned by Dalton's law should be avoided by proper planning of the activities of scuba diver intends to practice. The effects could cause a gas to a diver are based on the pressure of the gas in your body. This explains why Dalton's law is so important for divers and why they need to understand and prevent the consequences, he says. Partial pressure related problems can affect the human body in different ways, such as nitrogen narcosis or cause damage to the ear, among others, so divers should pay attention to these dangers and precautions.