Nitrox refers to any gas mixture composed of nitrogen and oxygen

Nitrogen percentage

Oxygen Percentage

Percentage inert gases




Nitrox refers to any gas mixture composed of nitrogen and oxygen; this includes normal air ('AIR') which is approximately 78% nitrogen and 21% oxygen, with around 1% inert gases. In Scuba diving, Nitrox is normally differentiated and handled differently from air. The most common use of Nitrox mixtures containing higher than normal levels of oxygen is in Scuba, where the reduced percentage of nitrogen is advantageous in reducing nitrogen uptake in the body's tissues and so extending the possible dive time, and/or reducing the risk of decompression sickness.

Nitrox is known by many names: Nitrox, Oxygen Enriched Air, EANx and EAN.
EANx (or EAN) is an abbreviation for enriched air nitrox. In 'EANx', the 'x' indicates the percentage of oxygen in the mix and is replaced by a number when the percentage is known; for example a 40% EANx mix is called EAN40. The two most popular blends are EAN32 and EAN36 (also named Nitrox I and Nitrox II)

1. Safely extend bottom time Nitrox is mainly used in Scuba diving to reduce the proportion of nitrogen in the breathing gas mixture. Reducing the proportion of nitrogen by increasing the proportion of oxygen reduces the risk of decompression sickness, allowing extended dive times without increasing the need for decompression stops. For example, a diver using Nitrox 36 may stay up to 50 minutes at 25 meters, while a diver using air may only stay a maximum 29 minutes at this depth.
2.Shorter Surface Intervals: A diver using nitrox absorbs less nitrogen for a given depth and dive time than a diver using air. This means that the nitrox diver has less nitrogen to off-gas during a surface interval, which can shorten the required surface interval to do another dive.
3. Longer Repetitive Dive Times Nitrox becomes especially useful for divers who engage in more than one dive per a day. A diver using nitrox will have a longer allowable bottom time on a repetitive dive than a diver using air because the diver using nitrox has absorbed less nitrogen. For example, after a dive to 20 meters for 32 minutes, a diver using Nitrox 32 can stay at 18 meters for a maximum of 58 minutes if he immediately reenters the water. However, a diver preforming the same series of dives on air may only stay at 18 meters for 20 minutes on his second dive

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