What does the term EAN32 signify in Nitrox diving?

EAN32 refers to a specific Nitrox mixture that contains 32% oxygen. In Nitrox diving, the naming convention for these gas mixtures typically follows the format "EANx," where "x" represents the percentage of oxygen in the blend. This notation is crucial because it helps divers understand the oxygen content of the gas they will be using during their dives.

Oxygen percentages are important in Nitrox diving because they influence the maximum operating depth and the risk of oxygen toxicity. A mixture like EAN32 would be chosen for dives where increased oxygen levels can help mitigate nitrogen narcosis and reduce surface interval times while still managing exposure to elevated oxygen partial pressures.

The other options describe mixtures or concepts that do not align with the standard naming for Nitrox gases. For instance, a mixture with helium would not fit the EAN nomenclature as it's specific to oxygen and nitrogen combinations. Moreover, air blends for deep diving do not conform to the Nitrox naming system, which focuses on oxygen-rich mixtures. A mixture containing no nitrogen would not typically be classified as Nitrox, as it fundamentally relies on a nitrogen and oxygen composition. Thus, understanding Nitrox mixtures and their formulas is vital for safe diving practices.