# An oxygen rich world **URL:** \ **Category:** Factual Questions\ **Created:** [February 22, 2009, 10:01pm UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980 "2009-02-22T22:01:46Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [February 23, 2009, 4:41am UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/21 "2009-02-23T04:41:43Z")
You might feel a bit light-headed, but you should be able to function. Besides, [it’s not the air you need to worry about](http://en.wikipedia.org/wiki/Titanoboa). ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [February 23, 2009, 4:55am UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/22 "2009-02-23T04:55:14Z")
> [@Washoe](#): > > A biology professor of mine once said that evolution no longer occurs on this planet because there’s “too much oxygen.” He said that evolution ended about 40,000 years ago. What was he talking about? He was an idiot, as **Q.E.D.** says. What the hell can oxygen have to do with some individuals being more capable of producing viable offspring than others due to genetic variation, and that variation making those offspring more capable of producing viable offspring in turn? ---
**Author:** ![puppygod](https://avatars.discourse-cdn.com/v4/letter/p/ce7236/32.png) [@puppygod](https://boards.straightdope.com/u/puppygod)\ **Post date:** [February 23, 2009, 10:26am UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/23 "2009-02-23T10:26:41Z")
> [@clairobscur](#): > > Poster have mentioned high concentrations of oxygen during the carboniferous. Will this be a problem when I’ll use my time travel machine to hunt dinosaurs (I’ll pay attention not to kill any butterfly, I promise)? Or is our body able to handle an oxygen rich atmosphere? > ETA : Just remembered that some people are given oxygen to breathe. Still, I leave my question, in case there would nevertheless be an issue with breathing all the time oxygen-rich air when you’re otherwise in good condition. Oxygen toxicity shouldn’t occur unless more than 50% (at 1 atm). I’m not sure what oxygen levels were historically present (hence may request for good cites), but it seems to be no more than 35% during carboniferous, and even less during dinosaurs times. So, no problem. Now, 78% is above dangerous level. Prolonged breathing of such air may damage your lungs. WAG: I’m not an expert, but from **Qadgop** cite and my understanding of biochemistry, 78% O2 is much to high for life - as we know it - to thrive. And if you try to analyze where all that oxygen is from, you hit a paradox. My understanding is that most atmospheric oxygen is biogenic - and without lifeforms it tends to be bound with other elements. So there have to be life that releases huge amounts of oxygen - but on the other hand, such huge amounts of oxygen are not suitable for most known lifeforms and tends to be absorbed, either by biochemical processes or by oxidation and violent burning. So for such atmosphere to exist there have to be a whole planetary ecosystem of lifeforms operating under different biochemistry than present lifeforms. So, bottom line of my WAG - if the air were 78% oxygen world would be very, very different. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [February 23, 2009, 9:10pm UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/24 "2009-02-23T21:10:23Z")
> [@ultrafilter](#): > > You might feel a bit light-headed, but you should be able to function. Besides, [it’s not the air you need to worry about](http://en.wikipedia.org/wiki/Titanoboa). 1 meter wide and 12 meters long? That extremely impressive. I’m surprised these super-snakes are never depicted in movies or documentaries. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [February 23, 2009, 9:11pm UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/25 "2009-02-23T21:11:46Z")
> [@puppygod](#): > > Oxygen toxicity shouldn’t occur unless more than 50% (at 1 atm). […] > > Now, 78% is above dangerous level. Prolonged breathing of such air may damage your lungs. Does someone knows why such high level of oxygen are toxic/damaging? And how damaging? Do we speak about a quick death or about months/years of health deterioration? ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [February 23, 2009, 9:58pm UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/26 "2009-02-23T21:58:44Z")
> [@clairobscur](#): > > 1 meter wide and 12 meters long? That extremely impressive. I’m surprised these super-snakes are never depicted in movies or documentaries. The discovery was just announced this year. Expect to see it on a screen near you sometime soon. ---
**Author:** ![puppygod](https://avatars.discourse-cdn.com/v4/letter/p/ce7236/32.png) [@puppygod](https://boards.straightdope.com/u/puppygod)\ **Post date:** [February 23, 2009, 10:08pm UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/27 "2009-02-23T22:08:24Z")
> [@clairobscur](#): > > 1 meter wide and 12 meters long? That extremely impressive. I’m surprised these super-snakes are never depicted in movies or documentaries. I’m sure they will. It’s very recent discovery - they were discovered like, two years ago, and not described until this year. [QUOTE=clairobscur] Does someone knows why such high level of oxygen are toxic/damaging? And how damaging? Do we speak about a quick death or about months/years of health deterioration? [/QUOTE] Probably more than you wanted to know about oxygen toxicity [is on wiki](http://en.wikipedia.org/wiki/Oxygen_toxicity). What is crucial, is partial pressure of oxygen. Since our atmosphere is about 100 kPa, then concentration of more than 50% of oxygen makes it partial pressure of above 50 kPa. This is enough to cause lung failure under prolonged exposition - that means days. It is not (or even 78 kPa is not) enough to cause death or any instant toxic response, as observed in hyperbaric conditions - you need at least some 160 kPa of O2. But 78 kPa O2 will mess up with a lot of biochemical processes on cellular level, so I think (again, I am not biochemist, mere amateur) that it would eventually cause serious health problems. Also, your lungs lose capacity within days. I tried browse for articles, but all of them seems to concentrate on hyperbaric oxygen toxicity in diving environment, rather than effects of prolonged exposures (above 12 hours) to elevated levels of oxygen. So, no cite yet. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [February 24, 2009, 1:45am UTC](https://boards.straightdope.com/t/an-oxygen-rich-world/486980/28 "2009-02-24T01:45:22Z")
If we had current levels of vegetation, fires would be endemic. The slightest ember would spontaneously burst into flames. Incidentally, I read somewhere recently that fires could not burn if the oxygen level fell below about 15%. At 30% oxygen we could expect to see humongous insects, since their size is limited by oxygen diffusion. Of course, our bodies could not take that level, but we would have evolved bodies that could. [Previous page](https://boards.straightdope.com/t/an-oxygen-rich-world/486980.md?page=1)