Which factor is crucial for planning a Nitrox dive?

The planned maximum depth and exposure time are fundamental aspects of planning a Nitrox dive because they directly influence the dive's safety and efficiency. Nitrox, a mixture of nitrogen and oxygen, allows divers to extend bottom times and reduce nitrogen absorption, but these benefits depend on the depth and duration of the dive.

Planning involves understanding how the specific percentages of oxygen in the Nitrox mix relate to the diver's exposure to pressure at depth. Higher concentrations of oxygen at greater depths can lead to oxygen toxicity, which is a serious risk. Therefore, knowing the maximum planned depth helps divers select the appropriate Nitrox mixture to maintain safe oxygen levels throughout the dive. Additionally, calculating exposure time is essential to avoid exceeding no-decompression limits and potential decompression sickness.

The other factors, while potentially relevant in dive planning, do not impact the critical calculations necessary for safely using Nitrox. For instance, a diver's weight affects buoyancy and gas consumption but does not influence the dive’s gas mix or depth planning. The availability of dive buddies is important for safety but does not determine gas management. Lastly, anticipating marine life adds interest to the dive experience but does not impact the dive planning process related to Nitrox utilization. Thus, effective dive planning hinges primarily on understanding