What is the relationship between PPO2 and depth for Nitrox diving?

The relationship between partial pressure of oxygen (PPO2) and depth is critical for understanding safety in Nitrox diving. As a diver descends, the pressure increases due to the weight of the water above. Since PPO2 is the result of multiplying the percentage of oxygen in the breathing gas by the ambient pressure, it follows that as depth increases, the ambient pressure increases, which in turn raises the PPO2.

When diving with Nitrox, which contains a higher percentage of oxygen than air, the risk of oxygen toxicity also becomes significant as PPO2 increases. Diving deeper with Nitrox can lead to dangerous levels of PPO2, which can have neurotoxic effects at certain depths. Thus, understanding this relationship is essential for divers to manage their exposure to oxygen and to plan their dives within safe limits.

Maintaining awareness of how PPO2 changes with depth helps divers avoid potential oxygen toxicity and maximizes their safety while using enriched air mixtures.