# If our bedrooms were air tight, would we be at risk of suffocating overnight?

**URL:** <https://boards.straightdope.com/t/if-our-bedrooms-were-air-tight-would-we-be-at-risk-of-suffocating-overnight/839815>\
**Category:** Factual Questions\
**Created:** [September 6, 2019, 8:16pm UTC](https://boards.straightdope.com/t/if-our-bedrooms-were-air-tight-would-we-be-at-risk-of-suffocating-overnight/839815 "2019-09-06T20:16:35Z")\
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**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\
**Post date:** [September 9, 2019, 10:40am UTC](https://boards.straightdope.com/t/if-our-bedrooms-were-air-tight-would-we-be-at-risk-of-suffocating-overnight/839815/21 "2019-09-09T10:40:25Z")

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> [@StarvingButStrong](#):
>
> Huh. This strikes me as strange. I mean, I know we exhale CO2, but I thought it was just a matter of disposing of a waste product we have no use for.
> 
> This sounds more like carbon dioxide should be considered a toxic gas, that inhaling it does something bad to you, biologically, not just takes up volume that could be more usefully filled with oxygen.

Absolutely. When [Apollo 13](https://en.wikipedia.org/wiki/Apollo_13#Survival_and_return_journey) had their, um “problem,” they had plenty of oxygen on board to make the return trip, in spite of one of their tanks exploding. However, the expected buildup of CO2 in the lunar module (where they planned to hunker down for the return trip) was a major concern. The LM was supposed to keep two people alive for two days, not three people for four days. The command module had enough chemical “scrubber” canisters for removing CO2, but they were designed for the command module and didn’t fit the system in the lunar module. In the end, they had to fabricate an adapter so they could fit the CM’s square canisters to the LM’s round sockets. They didn’t transfer back to the CM until shortly before reentry.

[A CO2 concentration of 8% in air](https://en.wikipedia.org/wiki/Hypercapnia) appears to be enough to render a person unconscious (possibly dead), even though such a mix would certainly contain enough oxygen to sustain life.

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