Which gas is primarily responsible for the risks of decompression sickness?

The primary gas responsible for the risks of decompression sickness is nitrogen. When divers descend underwater, the pressure increases, allowing the body to absorb more nitrogen from the breathing gas. During ascent, if the pressure decreases too quickly, dissolved nitrogen in the body can form bubbles. These bubbles can cause a range of symptoms associated with decompression sickness, from joint pain to potentially life-threatening conditions that affect the nervous system and other bodily functions.

The process is related to Henry's Law, which states that the amount of gas dissolved in a liquid is proportional to the pressure of the gas above the liquid. When divers ascend, the reduction in pressure means that nitrogen comes out of solution rapidly, leading to the formation of bubbles in the tissues and bloodstream.

Understanding the behavior of nitrogen in the body is crucial for divers, as managing ascent rates and making safety stops can significantly reduce the risk of decompression sickness. Other gases, such as oxygen, helium, and carbon dioxide, do have essential roles in diving but do not pose the same significant risk for decompression sickness as nitrogen does.