Humans can really breath Mars air?

[cjameshuff]

Of course, this is will not be enough. The CO will have to be removed too. While scrubbing CO₂ is well understood and usually involves the use of either Lithium Hydroxide (as per Apollo) or Sodium Hydroxide, scrubbing CO is not so easy, and it has to be got down to a very low level. Even as little as 35 ppm will cause dizziness and headaches after six hours of continual exposure. Its going to have to come down to 5 - 10 ppm at least.

Seems like it ought to be pretty straightforward. Catalytic oxidizers and CO detectors are both in rather widespread use.

[cjameshuff]

I suppose it might also be possible to extract the O₂ from atmospheric CO₂, but that is a very stable molecule and I'm not sure it would be as easy as getting it from certain minerals. Ilmenite (iron titanate, FeTiO₃) seems to be a favorite in proposals to make O₂ on the moon.

The moon has a distinct shortage of a CO2 atmosphere. It's a lot easier to to get O2 from CO2 than from most minerals. I don't know why you would attempt the latter on Mars.

[ka9q]

The moon has a distinct shortage of a CO2 atmosphere. It's a lot easier to to get O2 from CO2 than from most minerals. I don't know why you would attempt the latter on Mars.

I don't know much about CO₂ cracking techniques but I have read about lunar O₂ production as I agree with those working on it that it's absolutely essential to any kind of affordable return to the moon. Quite a few experimental chemical reactors have been built, and nearly all of them use ilmenite as the raw material. Apparently it requires much lower temperatures than other minerals, nearly all of which contain oxygen in some form.

One major benefit of cracking ilmenite rather than CO₂ on Mars is that it produces metallic iron as a byproduct, and that could be very useful for construction. You also get TiO₂, though I don't know if that's especially useful in lunar construction (I suppose it is if you like to paint your walls).

[ka9q]

Seems like it ought to be pretty straightforward. Catalytic oxidizers and CO detectors are both in rather widespread use.

Right. Maybe you could start with a catalytic converter to destroy the NO and O₃. Then add O₂ and pass over another catalyst to oxidize the CO and H₂CO (and any CH₄ if it actually exists). Finally remove the CO₂ and you're left with a mixture of O₂, the inert gases in the Martian atmosphere, and a little additional H₂O vapor. Store that for use whenever additional diluent is needed.

Since the diluent is usually reused indefinitely, the only reason to store a lot of it is to maintain normal habitat pressure during a leak emergency. Otherwise you'd have to maintain it with pure O₂, which would either create a serious fire hazard (if total pressure is maintained) or a serious risk of the bends (if only the O₂ partial pressure is maintained).

[Glom]

But what's the partial pressures? That's more relevant to the human.

Not really, because the Martian atmosphere is so thin (< 1% of earth's surface level pressure), and toxic CO₂ is so much of it, that whatever useful gases there are (Ar, N₂) will have to be compressed a lot to form part of a human-breathable atmosphere. So percentages are what's important.

I think I misunderstood the question.