What happens to nitrogen at low pressures during a dive?

During a dive, changes in pressure affect the behavior of gases, including nitrogen. At low pressures, particularly when ascending from a dive, nitrogen that had been dissolved in the body's tissues under higher pressure can come out of solution and form bubbles. This phenomenon is primarily a result of Henry's Law, which states that the amount of a gas dissolved in a liquid is proportional to the pressure of the gas above the liquid. When the pressure decreases, the solubility of the gas decreases, leading to the formation of bubbles in the tissues and bloodstream, which can be dangerous and may cause decompression sickness (often referred to as “the bends”).

Recognizing the behavior of nitrogen at varying pressures is crucial for divers to avoid potential health risks associated with rapid ascents and to understand the need for controlled, gradual ascents to allow nitrogen to safely leave the body without forming harmful bubbles.