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Weir's new novel Artemis: A Novel just arrived on my kindle.

Chapter 1: A rich guy lights a cigar, with an apparently ordinary lighter, in a 100% O2 atmosphere and

he enjoys it.

Why

doesn't he and everyone in the room instantly burn to a crisp?

The atmosphere pressure is only 20% of Earth's, that can't be the reason, can it?

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    At 20% atmospheric pressure, the partial pressure of O2 would be equal to here on Earth (where it makes up 21% of the atmosphere). How that affects things burning... perhaps you'd best ask over at Chemistry Stack Exchange. Obviously anything that uses other atmospheric gases as catalyst would be affected, but that shouldn't come into play in your scenario. On the other hand, the expansion of flame products ought to be quite different in a low pressure atmosphere.
    – Ben Voigt
    Commented Nov 15, 2017 at 3:03
  • The problem with Apollo 1 was twofold: it was 100% pure oxygen and also it was pressurized above one atmosphere to prevent any outside air from leaking in. The high pressure was an important factor in the fact that the fire burned hot enough to weld metals together. And even then it wasn’t instant, it was just fast and since the hatch opened inward it was impossible to open against the interior pressure in time to rescue the crew. You might take this line of questioning over to the physics Stack.
    – Todd Wilcox
    Commented Nov 16, 2017 at 0:44

2 Answers 2

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Fire is the result of an oxidation reaction. It requires heat, fuel, and an oxidizer (usually oxygen). So oxygen itself does not burn.

If a fire would otherwise be oxygen-limited, then yes, the atmosphere content will matter quite a bit. But if the fire is fuel-limited, you can add all the oxidizer you want, and it won't affect the spread of the fire much. I think the cigar should burn normally.

The lighter might behave differently, since it's actually mixing fuel and air in a particular ratio. But the difference might not be much, since there's no leftover fuel in a normal atmosphere anyway.

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    Please don't answer questions that are clearly off-topic. It only encourages people to ask them
    – Valorum
    Commented Nov 15, 2017 at 9:01
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Yes, you are absolutely correct. They would all be burnt to a crisp (source).

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    The Apollo astronauts on the moon missions used 100% Oxygen atmosphere and didn't suffer oxygen poisoning. popsci.com/…
    – Tim
    Commented Nov 15, 2017 at 2:34
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    But the Apollo 1 astronauts were killed when a spark from a wire set every thing even remotely combustible ablaze.
    – Emsley Wyatt
    Commented Nov 15, 2017 at 2:39
  • I thought the oxygen poisoning was a cool bonus but am not 100% sure on how that changes with pressure so I have removed that part and just left the base answer. Any research or links to how toxicity is effected by pressure would still be helpful to the answer
    – Jesse
    Commented Nov 15, 2017 at 2:55
  • From what I've read, oxygen poisoning occurs only if the air pressure is much higher than natural 1 atmosphere (hence it is a serious concern for divers)
    – Yasskier
    Commented Nov 15, 2017 at 2:56
  • 3
    Please don't answer questions that are clearly off-topic. It only encourages people to ask them
    – Valorum
    Commented Nov 15, 2017 at 9:01

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