What factor primarily affects the Maximum Operating Depth for Nitrox mixtures?

The Maximum Operating Depth (MOD) for Nitrox mixtures is primarily influenced by the oxygen content of the mixture. Nitrox is a blend of nitrogen and oxygen, and the proportion of oxygen in the gas mixture dictates how deep a diver can safely descend.

As a diver descends, the pressure increases, which consequently increases the partial pressure of oxygen in the breathing gas. Each Nitrox mixture has a specific threshold known as the maximum allowable partial pressure of oxygen, typically around 1.4 ATA for recreational diving. If a diver descends deeper than the MOD for their specific Nitrox mixture, the partial pressure of oxygen can exceed safe limits, posing serious risks such as oxygen toxicity, which can lead to central nervous system effects or even convulsions.

Understanding this relationship between oxygen content and depth is crucial for dive planning and safety, as it guides divers in selecting appropriate blends based on their intended depth and the associated risks. While factors such as total dive time, water temperature, and a diver’s experience level can affect a dive in various ways, they do not have the same direct impact on the calculation of MOD as the oxygen content does.