Which statement about Nitrogen loading is true?

Which statement about Nitrogen loading is true?

• A. Nitrox reduces nitrogen partial pressure but is not sufficient for deep dives.
• B. Nitrox reduces all gases completely.
• C. Nitrox increases nitrogen partial pressure.
• D. Nitrox is not used in any diving scenario.

Answer: (A)

Nitrogen loading depends on how much inert nitrogen your tissues absorb under pressure, which is driven by the partial pressure of nitrogen in the breathing gas. Nitrox has a higher fraction of oxygen and a lower fraction of nitrogen than normal air, so at a given depth the partial pressure of nitrogen is lower and less nitrogen dissolves into tissues. That reduces nitrogen loading and can lessen decompression needs for many recreational dives. But this gas mix does not remove nitrogen completely, and the higher oxygen content raises the partial pressure of oxygen. At deeper depths, the increased oxygen partial pressure can reach toxic levels, so Nitrox cannot be used for very deep dives where PPO2 limits would be exceeded. That’s why Nitrox is useful for shallower recreational dives but not sufficient on its own for deep dives. The other statements aren’t accurate: Nitrox does not reduce all gases completely or increase nitrogen partial pressure, and Nitrox is indeed used in diving scenarios to manage nitrogen loading.

Nitrogen loading depends on how much inert nitrogen your tissues absorb under pressure, which is driven by the partial pressure of nitrogen in the breathing gas. Nitrox has a higher fraction of oxygen and a lower fraction of nitrogen than normal air, so at a given depth the partial pressure of nitrogen is lower and less nitrogen dissolves into tissues. That reduces nitrogen loading and can lessen decompression needs for many recreational dives.

But this gas mix does not remove nitrogen completely, and the higher oxygen content raises the partial pressure of oxygen. At deeper depths, the increased oxygen partial pressure can reach toxic levels, so Nitrox cannot be used for very deep dives where PPO2 limits would be exceeded. That’s why Nitrox is useful for shallower recreational dives but not sufficient on its own for deep dives.

The other statements aren’t accurate: Nitrox does not reduce all gases completely or increase nitrogen partial pressure, and Nitrox is indeed used in diving scenarios to manage nitrogen loading.