We are not the owner of this video, no intentions to infringe any copyrights.
We are not the owner of the video, no intention to infringe any copyrights.
Why can’t we breathe on pure oxygen underwater?
Yes. We can breathe pure oxygen (100%) underwater, but it’s only up to 6m in depth. After 6m, the oxygen become toxic to our human body. Remember the theory on Partial Pressure? (I try to be as layman as possible)
Atmosphere is made of 78.09% of Nitrogen, 20.95% of Oxygen, 0.93% of Argon, 0.039% Carbon Dioxide plus other traces of gases. Hence, we rounded it off to 79% of Nitrogen & 21% of Oxygen. Our body only utilities 5% of the 21% of Oxygen we inhale, the rest will be exhaled to the atmosphere again.
Partial Pressure of Oxygen on Sea Level = 0.21 bar. (which means 1 bar of atmosphere air, 0.21 bar is Oxygen, the rest – 0.79 bar is Nitrogen)
However when Oxygen is breathed under pressure, it will become toxic at Partial Pressure of Oxygen = 1.6 bar.
Sign and Symptoms of Oxygen Toxicity
Convulsion; Blurred Vision; Ringing in the ears; Nausea; Twitching; Irritability; Dizziness.
If you breathe 100% Oxygen, at 6m depth the Atmospheric Pressure is 1.6 bar, hence the Partial Pressure of Oxygen is also 1.6 bar.
However if you breathe on normal compressed air, to reach the Partial Pressure of Oxygen = 1.6 bar, you have dived to the depth of around 66m. Unfortunately, Recreational Diving is limited to 40m, don’t be foolish to dive to 66m.
Enriched Air or Nitrox
Any compressed air which Oxygen is more than 21%, it’s known as Enriched Air, this required you to take the PADI Enriched Air Diver Course or Nitrox Course by other agencies. The most common Enriched Air used are 32% or 36%.
Planning dive using Enriched Air is very important. You have to calculate the maximum depth and emergency depth depending your Partial Pressure of Oxygen.
Enriched Air Course is not a Technical Dive Course, it is still Recreational Dive Course, using different dive profile or rather dive table.