The winning survey on HowStuffWorks today was “What if I breathed 100% oxygen?” I was just wondering. . .what if we really did?
Well, assuming our systems could take 100% oxygen, we’d eradicate smoking 
.
Seriously, I don’t think it would matter 'cause the whole world would have burnt up before we evolved.
Jules Verne wrote a story about this over a hundred years ago. I can’t recall the title, offhand. But I suspect that his speculation isn’t quite correct.
I seem to remember reading about a 19th century experiment where a mouse was placed in a container provided with pure oxygen. He ran himself ragged and died. This may have been conducted by Joseph Priestly (discover of oxygen, if memory serves).
I think too much oxygen is a bad thing. Commander Edward Ellsberg was for years one of the top navy salvage and diving experts. In fact he is the guy who invented the underwater cutting torch.
In his book about the raising of the US submarine (I think it was the S4) that sank in Long Island Sound in the late 1920’s he described the physical problems the divers had, (not the bends) such as loss of weight and extreme fatigue because of working for an extended time in high pressure air.
Oxygen is toxic in high concentration and so active that it rapidly oxidizes (in other words burns up) body tissue. An excess, according to the Britannica upsets the O[sub]2[/sub] to CO[sub]2[/sub] ratio leading to hyperventilation, numbness, dizziness and other physical problems.
Y’know, love is like oxygen – you get too much, you get too high; not enough and you’re gonna die.
But don’t hospital patients get 100% oxygen, especially if they’re in respiratory distress? Or is it mixed with air in some percentage?
My WAG is that ifyou continued breathing straight oxygen, you’d have more free radicals, which can damage body tissues.
You are right easy e, sometimes people do require delivery of 100% oxygen. However, prolonged exposure to such high concentrations of oxygen is a bad thing and can lead to a number of serious problems including severe lung injury.
Sometimes you don’t have a choice - the patient will die without 100% oxygen. Generally, though, you try to use the lowest possible concentration of oxygen in order to prevent such problems from arising.
Here is an old paper that gives a sense of the problem.
I think it’s Doctor Ox’s Experiment, which has also been made into an opera.
From the physiological point of view pure oxigen at three pounds per sq inch is the same as your regular atmosphere (Arthur C. Clarke in The Promise of Space). The Mercury program used this approach (and a string of errors led to the fire where three austronauts died).
Absolutely correct, sailor. According to Michael Collins in Carrying the Fire (his documentary about the U.S. space program), this continued to be the case through the end of the Apollo program. After the Apollo I disaster, they used enhanced safety precautions, naturally … Oxygen makes up about 20% of the atmosphere at sea level. While an environment of 100% oxygen at one atmosphere pressure is extremely dangerous, an environment of 100% oxygen at 0.2 atmospheres pressure (the same partial pressure as in ordinary air at 1 atmostphere) is perfectly healthy. Go figure.
As already mentioned, pure oxygen is toxic whenever it’s breathed either over a long period of time, or else at a higher than atmospheric (1 Bar) pressure. The former gives rise to chronic oxygen toxicity (the symptoms of which have been mentioned above); the latter precipitates acute oxygen toxicity (ACT) - characterised by ‘fits’, similar in appearance to those suffered by epileptics.
The exact pressure (strictly speaking, partial pressure of oxygen - ppO2 - in any given breathing mix) at which acute oxygen toxicity is triggered varies for different individuals, times, etc, but it is a general rule in recreational diving that to avoid it, you should keep your ppO2 to below 1.3 Bar.
There’s good reasons for divers to use ‘oxygen-rich’ mixtures, but the risks of ACT are such that this kind of diving requires special training.