What does 'nitrox' refer to in diving?

Nitrox refers specifically to a breathing gas mixture that contains a higher percentage of oxygen than the standard atmospheric air, which is composed of approximately 21% oxygen and 79% nitrogen. In diving, nitrox mixtures typically contain oxygen levels ranging from 22% to 40%. The primary benefit of using nitrox is that it reduces the amount of nitrogen a diver absorbs during a dive, allowing for longer bottom times at certain depths and shorter surface intervals during repetitive dives. This can help in minimizing the risk of decompression sickness, as nitrogen is the gas that can accumulate in a diver's body due to increased pressure underwater.

Understanding nitrox and its advantages is crucial for divers who want to extend their dive times or plan multi-dive days. Knowledge of nitrox also prepares divers to understand additional considerations, such as the effects of elevated oxygen pressures on the body, particularly at greater depths where oxygen toxicity may become a concern.