At deeper depths, what factor significantly changes when using Nitrox compared to traditional air?

Using enriched air nitrox at greater depths significantly affects the partial pressure of oxygen, making this the correct answer. Unlike regular air, which is composed of approximately 21% oxygen and 79% nitrogen, nitrox blends typically have higher oxygen concentrations. As a diver descends, the surrounding pressure increases, and this increased pressure affects the partial pressure of gases.

For nitrox divers, the higher proportion of oxygen means that as they go deeper, the partial pressure of oxygen rises more rapidly than it would with air. This can have physiological implications, such as an increased risk of oxygen toxicity if the partial pressure of oxygen exceeds certain thresholds.

Understanding this change is crucial for divers, as it influences the planning of depth and duration of dives when using nitrox, as well as the need for careful monitoring of oxygen exposure during the dive. Managing the risks associated with increased partial pressures of oxygen helps ensure the safety of dives conducted with enriched air nitrox.