Which gas is primarily increased in Nitrox blends compared to air?

In Nitrox blends, oxygen is the gas that is primarily increased compared to air. Standard atmospheric air contains approximately 21% oxygen and 79% nitrogen, while Nitrox is a mixture that typically has a higher percentage of oxygen, such as 32% or 36%.

This increase in oxygen content is significant for divers because it allows for enhanced breathing gas during diving, leading to reduced nitrogen absorption and lower risk of nitrogen narcosis and decompression sickness. The higher oxygen concentration in Nitrox also enables divers to extend their bottom times at certain depths compared to using regular air, where nitrogen is the limiting factor.

Understanding the composition of Nitrox is crucial for divers, as it directly impacts their dive planning and safety measures. The additional oxygen can provide benefits at depths where nitrogen's solubility is a concern, allowing for greater flexibility in dive duration and safety practices.