[neilep (OP)]

Dear Oxygenologists,

see this desert ?

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Arid, dry, cold at night, hot in the day !



see this rainforest ?

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Humid, temeperate, no extremes



see this sea ?

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Wet, wet, wet.........





At Sea level.......does the oxygen differ dramatically between the three ?...or is the oxygen of the world pretty evenly distributed ?..and what about the city ?

ewe'see....I don't know !!.....do ewe ?

[Karen W.]

I understand that higher altitudes have thinner oxygen levels. My best guess would be that the oxygen would be in higher concentrations over that most beautiful Rain forest you have shown us! All those beautiful trees  producing such lovely oxygen for us to breath. knowing there are plants etc most everywhere, I still think it is better there. cities with all the smog and such make me think the country is better for oxygen rich air. Maybe someone can tell  us if this is right?

*I have just added to this because I missed the part where you said at sea level ... so scratch my answer.. LOL at sea level I still think forests and such may be more oxygen rich environments.. but probably not enough to make a difference..* (added after the original!)

[Carol-A]

The atmosphere is constantly moving, so I doubt there is huge difference anywhere at sea level.... it all gets mixed up!

[another_someone]

The atmosphere is constantly moving, so I doubt there is huge difference anywhere at sea level.... it all gets mixed up!

Not a huge difference, but if we can meddle with the levels of other gasses over cities (e.g. levels of ozone and NO_x), then it follows that local levels of O₂ must also change, but since so much of the air is already O₂, so making a significant change to such a large volume of gas would take the input or removal of an enormous amount of gas.

One question must be with regard to the processes that convert CO₂ to O₂, and where are they going one.  Nonetheless, since the amount of O₂ in the atmosphere is about 200,000ppm, and the amount of residual CO₂ in the atmosphere is only about 300ppm, so even if all of it was converted to O₂ at one location on the Earth, that is would still only raise the amount of local O₂ by about 0.3%.  Equally, if processes (whether anthropogenic, or biological) were to double the amount of CO₂ and remove the equivalent amount of O₂, it would still only make about 0.3% difference to the amount of O₂ in the atmosphere.  None of this is particularly significant.

Obviously, when one is talking about catastrophic events (e.g. volcanic eruptions), this will have a significant in the amount of air, and thus the amount of oxygen, in the local vicinity.  I am not sure how much influence other displacement events, such as rainfall or fog, might effect air levels; but since none of these actually cause suffocation, it cannot be more than a few percent.

[JimBob]

If you consider gaseous O₂ then it is relatively the same all over the world. If total oxygen, then there is more sequestered in rocks than there is in the atmosphere. Think of all the rust that is on an abandoned farm. Then consider how much of the earth has red sand, red muds, etc. (iron oxide). On top of that, oxygen is bound in crystal structures for a LOT of mineral.

So the amount of oxygen in the earth is more than that in the atmosphere.

[another_someone]

If you consider gaseous O₂ then it is relatively the same all over the world. If total oxygen, then there is more sequestered in rocks than there is in the atmosphere. Think of all the rust that is on an abandoned farm. Then consider how much of the earth has red sand, red muds, etc. (iron oxide). On top of that, oxygen is bound in crystal structures for a LOT of mineral.

So the amount of oxygen in the earth is more than that in the atmosphere.

And don't forget the amount of oxygen bound up in water.