Nitrox and the acronym EANx solely refer to mixtures with oxygen concentrations (FO2) higher than?

Nitrox, commonly referred to in diving as EANx (Enriched Air Nitrox), specifically pertains to gas mixtures that contain a higher concentration of oxygen than the standard 21% found in normal air. This distinction is important for divers, as higher oxygen concentrations can help reduce nitrogen absorption, thereby mitigating the risk of decompression sickness and extending bottom time at certain depths when properly managed.

When referring to mixtures with an oxygen concentration (FO2) above 21%, this means that any Nitrox blend increasing the oxygen content above the ambient level in air qualifies as Nitrox. For example, typical mixtures used in diving might include 32% or 36% oxygen. Understanding this definition allows divers to safely utilize enriched air blends while taking necessary precautions to accommodate the effects of elevated oxygen levels at various depths. Thus, the correct threshold indicating when a mixture is classified as Nitrox (EANx) begins at an oxygen concentration greater than 21%.