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Why Is Nitrox Used When Scuba Diving?

Last updated March 14, 2022| Diving

What Is Nitrox?

In terms of recreational diving, rich gas nitrox (EAN) is any mixture of nitrogen/oxygen with a concentration of more than 21 percent oxygen in normal air – 32 percent oxygen is more common. And tanks often filled with EAN Nitrox has marked on the tank strip.

The mixture percentage has written somewhere near the tank valve. This high oxygen content and nitrogen ratio are relatively low, allowing divers to lengthen the decay limits, shorten surface time intervals. And obtain an additional protective buffer for decomposition sickness under certain diving conditions.

How Does Nitrox Work?

When you dive, nitrogen dissolves in your bloodstream from the air you breathe due to water pressure. As the pressure increases, the nitrogen dissolves. Once a certain nitrogen concentration builds up, you should slowly come to the surface to avoid mandatory decomposition stops or DCS. For example, based on U.S. naval diving tables, a diver in the air at about 100 feet should reach his or her dissociation limit and arrive 25 minutes later.

diving with nitrox

The maximum time for a 60-foot diver is one hour. When you replace some nitrogen with extra Oxygen, there is less nitrogen, which means that it does not dissolve quickly, and there is no further decomposition limit. This concept is called equivalent air depth (EAD). For example, 36 percent of 105-foot-tall divers will release nitrogen into their blood and tissues. Therefore, the diver’s average dissociation limit ranges from 20 minutes to 40 minutes, twice as long as the downtime.

What Are The Benefits Of Diving Nitrox?

There is a misunderstanding that you can dive deeper, but in reality, it is the opposite, but you can dive longer. Another misunderstanding is that if you take a diving vacation using nitrox, it will make you tired after a lot of diving. Although there is no actual data to prove this, it is repeating by many divers.

You have time and depth when diving. It is because when you dive, your body absorbs the air you breathe, and when you are under pressure, it absorbs more of you than the surface. So, it becomes a problem as you go up and the pressure drops, and if it is too fast, it allows those gases to bubble out.

As you know, the body uses Oxygen for a variety of reasons. However, it lacks nitrogen and is, therefore, more likely to form bubbles. The idea behind rich air is that if you reduce the amount of nitrogen, the risk of bubbles is reducing. More energy and less nitrogen mean that your body does not have to work hard to get rid of excess. The chemical reacts when there is pressure, which is not a problem because the body does not use nitrogen, and the number of nitrogen molecules decreases.

On the other hand, as Oxygen is using and more pressure is applying, this rapid reaction can become a problem, and each breath receives more Oxygen. If this is not properly limited, it can have serious consequences when submerged.

What Are The Dangers Facts Of Diving With Nitrox?

While useful and essential for life, Oxygen can be dangerous at high concentrations, leading to severe oxygen poisoning and having very bad side effects, from visual distortions to distractions that can lead to drowning. Any percentage of Oxygen can be toxic at high enough pressures. But to dive into the air, you have to go deeper than 220 feet to experience severe oxygen poisoning.


Significantly, the danger of nitrox is that it brings that ability into the depths of recreational diving. Divers using nitrox have two factors to consider when considering oxygen poisoning: the amount of exposure or oxygen pressure in the lungs, and the second is the length of exposure. So, when combining these two factors are called the oxygen limit.

The pressure limit component of the oxygen limit is calculating at half pressure, which can find by multiplying the percentage of Oxygen gas in your tank by the atmospheric pressure at your designed depth. Technical divers will often dive to an oxygen partial pressure of not less than 1.6 PPO2 for relatively short periods, usually no more than 45 minutes. After each exposure to this level, they must remove some amount of Oxygen before diving again.


Humans clearly cannot breathe underwater. Primarily, it is why you should have a scuba tank with you during your dive. These tanks usually contain filtered air, trimix, or nitrox. Divers generally use nitrox air in their tanks if they want to spend more time underwater.

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