In Nitrox diving, what does the term 'oxygen exposure' refer to?

The term 'oxygen exposure' in Nitrox diving specifically refers to the total duration and partial pressure of oxygen that a diver experiences during a dive. This concept is critical in understanding the potential physiological effects of elevated oxygen levels when breathing enriched air mixtures, such as Nitrox.

When a diver uses Nitrox, the mixture typically contains a higher percentage of oxygen compared to regular air. The total oxygen exposure is calculated based on both the time spent at certain depths (where the partial pressure of oxygen is increased due to the surrounding water pressure) and the concentration of oxygen in the gas mixture. Exceeding safe limits of oxygen exposure can lead to oxygen toxicity, which can have severe and potentially life-threatening consequences.

Understanding this relationship helps divers plan their dives more safely, manage their bottom times effectively, and avoid the risks associated with oxygen toxicity.