How does planning Nitrox dives differ from planning air dives?

When planning Nitrox dives, managing your exposure to oxygen is a critical factor. Unlike air, which consists of approximately 78% nitrogen and 21% oxygen, Nitrox can have varying proportions of oxygen, typically higher than 21% (e.g., 32% or 36%). This change in oxygen content significantly affects the allowable depth and time of the dive due to the risk of oxygen toxicity.

As the percentage of oxygen increases, the maximum operational depth (MOD) for a dive decreases. Therefore, divers need to calculate the MOD based on the specific blend of Nitrox they are using to avoid exceeding safe oxygen exposure limits during their dive. Additionally, understanding the no-decompression limits (NDLs) becomes more important when using Nitrox, as the dive profile can often result in shorter bottom times due to increased oxygen exposure.

While managing nitrogen exposure is still relevant, especially in relation to decompression modeling and overall dive planning, the primary concern with Nitrox is how the increased levels of oxygen can impact your safety when diving.