Discussion in 'Science & Society' started by Photizo, Nov 29, 2009.
Right - but the partial pressure of oxygen (which is what humans care about) is changing.
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and with any reduction in oxygen pressure due to over consumption leads to what? At sea level?
And must convert it to carbon dioxide. If we burn so much carbon that we get up to 5% CO2 by volume, thus reducing O2 levels by approximately the same amount by volume, then we will suffocate ourselves and kill off most of our biome. At that point we will stop using oxygen because most of us will be dead. Thus it is self-regulating.
Nope. Again, you run into other limits far before you deplete atmospheric oxygen.
And what? That's how it works. That's why you get out of breath more rapidly in Denver, and why you need supplemental oxygen above about 15,000 feet.
see edited post ...sorry
put human sensitivity in context a little:
Have you ever felt the difference of leaving a crowded auditorium and stepping into an empty foyer. (re: breathing - oxygen levels)
Or leaving a big city and hitting the empty road.
Our "comfort zone" is heavily dependent on oxygen levels
That's not oxygen; that's CO2. What most people consider "not enough oxygen" is actually too much CO2. We don't have much in the way of oxygen receptors but we are very sensitive to CO2 levels.
Nope, not even close. If you can be comfortable outside in Boulder, Colorado then any discomfort you feel in a sea level auditorium/car/city has nothing to do with O2.
think of the above in terms of reduction rather than increase and you get what i m on about regarding human sensitivity.
Again, not supportable by science. No matter what people "fancy" about their "breast."
yes CO2 is also a an issue no doubt about it, but when combined with O2 depletion CO2 issues obviously gain all the attention.
Or not combined with O2 depletion.
Have you ever had to use supplemental oxygen?
so why do medical staff install oxygen at earliest chance when dealing with most medical emergencies.
"Your in a crowded auditorium with poor ventilation."
Every one is converting ambient oxygen into CO2. Obviously O2 goes down and CO2 goes up..
How is this not ambient O2 depletion?
or ask yourself the question:
Is altitude sickness driven by ambient CO2 levels or ambient O2 levels?
It is - and it is converted to CO2. When CO2 is even slightly elevated (say, goes from 400ppm to 1000ppm, as can occur in a crowded space) then you start feeling it. That means that CO2 is up 600ppm and O2 is down 600ppm. 600ppm reduction in oxygen means you go from 21% oxygen to 20.4% oxygen. That's the same as going up about 1000 feet in the air.
Let's compare it to Boulder, Colorado. At sea level outside the auditorium you are at 159 mmhg O2. If all those people breathe all that oxygen (at which point the CO2 levels are going to make you drowsy and even sick if you are there for long enough) then you are down to 154 mmhg O2. If you are standing outside on a sunny day in Boulder, CO breathing that clean mountain air, you are going to be at 131 mmhg O2.
Where do you think you will feel better? In that stuffy auditorium or outside breathing the mountain air in Boulder?
breathing oxygen rather than CO2 that's where...
at least we can agree that oxygen/Co2 ratios are a hot potato for human physical comfort/life.
and it is not just CO2 but both
There is another issue regarding Oxygen that I am going to guess at.
In humans Oxygen has a "cooling" effect. It acts as a natural refrigerant. When oxygen levels are diminished body "core" temperature (not just standard body temperature) is increased. In heightened CO2 conditions core temperature would increase. (due to inherent increase in stress)
Like running a fever that shows no standard body temperature increase. A state of feeling unwell with out fever.
So you agree that standing outside in Boulder would be more comfortable than being in that stuffy auditorium - even though you are getting a lot less oxygen. Cool.
Again, have you ever needed/used supplemental oxygen?
well of course I would be breathing O2 and not CO2. Which is better than breathing CO2 filled auditorium.
Even base camp at Everest would be better...
Ever suffered severe blood acidosis? (Hypercapnia)
Due to oxygen deprivation?
Again, I agree. But you just gave an example where getting much less oxygen than you get at sea level would make you feel better than getting more oxygen in a stuffy auditorium. Thus your claim that very small reductions in oxygen make large changes in human comfort isn't really supportable, since in that case the opposite is true.
No, I haven't. Have you ever needed/used supplemental oxygen?
just step out of a crowded auditorium and you get a dose of supplimental oxygen.
Have I ever left a room due to a lack of oxygen... many times.
But to answer your question directly... yes of course, 5 incidences of inexplicable spontaneous pneumothorax (collapsed lungs) ending with resection of the left would make me an "armchair" expert I guess. Please Register or Log in to view the hidden image!
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