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

Factual Questions
1

I know our building methods are no where near being airtight, in fact, I think I read somewhere the air in a room generally turns over multiple times an hour.

But what if didn’t? What if absolutely no air leaked through closed windows or doors, or through cracks or the electric ducts and so forth? If, when you retired to your bedroom at night, closing your door sealed the room off completely?

How much oxygen does a human actually use? How does that compare with how much oxygen there is in a normal sized bedroom filled with normal Earth atmosphere? Would we be fine, or wake up gasping for air in the morning, or <gasp> not wake up at all?

2

Nitpick: As I understand it, it’s not the lack of Oxygen that would kill you, but the build up of Carbon Dioxide.

(I don’t know the answer to the question, but I bet NASA does.)

3

From articles such as this one, Carbon dioxide generation rates for building occupants, in Indoor Air. 2017 Sep; 27(5): 868–879, a general rate of CO2 generation per adult human in 0.005 L/s, at a typical ventilation rate of 7.5 L/s. CO2 has a variety of toxic concentrations, from 100,000 PPM, or 10%, immediately dangerous to life, to 30 minutes at 50,000 PPM resulting in intoxication, to a 8 hour total weighted average of 5,000 PPM. All from this reference, NIOSH’s page on CO2. The PPM are listed as weight of CO2 per cubic meter. (listed as mg/m^3) at the reference.

The 8 hour TWA is 9,000 mg/m^3

How big is your bedroom and how long are you sleeping shut in?

Creditdonkey seems to think 309 sq feet is a typical master bedroom. 8 foot ceilings used to be the norm, but 9 feet ceilings in many rooms are in vogue. Call it 2700 cubic feet, or 76,455 L or so. (76.455 m^3) Let’s make it 8 hours, or 28,800 seconds. You said we, so let’s have two people in the room.

0.00528,8002 = 288 L of CO2 exhaled.

CO2’s density at STP is ~2.0 kg/m^3. 2 kg * 10^6 mg per kg * 288 L * (1 m^3/1000 L) = 576,000 mg.

Now spread that CO2 over the 76.455 m^3 of the room. I get 7,533 mg/m^3. Less than the 8hr TWA, but getting uncomfortably close. You’d probably notice it.

Obviously this is a gross simplification. I wonder how much the humidity would rise in this environment?

4

There is some evidence that local build up of carbon dioxide in well sealed bedrooms has negative effects. I don’t know of any good scientific studies, but here are three articles from Scott Alexander, who become interested and also asked his internet followers to conduct a non-scientific experiment regarding it. The results are, at least, interesting. I leave it to our doctors and scientists here to comment on the results. Scott is both a medical doctor and psychiatrist.

Thin Air explores apparent links between altitude-related (and possibly O2) obesity levels.

Open Door Policy discusses localized effects of well sealed rooms and CO2 buildup on mental health and well-being.

Nighttime ventilation survey is a followup of the survey results from his followers, who were instructed to try various ventilation methods and report back.

None of this is deep science and math, and I found them all quite readable. Hope it sheds some light, or at least shows other paths to investigate.

Edit: Ninja’d by Gray Ghost with real science. I defer to his math on this, but still find the SSC articles interesting.

5

I’d be interested if the BMI and altitude stuff also was true at places like Scott Station at the South Pole. I’ve read that the altitude (9300 feet) has effects like wounds not healing readily, listlessness, and other physiological and psychological effects. Though I doubt that’s due to CO2 buildup so much as mild hypoxia.

Edit: Oooh, here’s a large pool of people to look at: modern nuclear submariners. Don’t they run the atmosphere in a modern nuke at slightly hypoxic levels? I’m sure they keep the CO2 in check, but I’d bet it’s still above ambient in the environment on the surface. And the Navy’s been doing it for 60 years now, with a broad cross section of male individuals.

Thank you for the compliment on the math, but it’s obviously a gross oversimplification of the problem. I’d been curious about that kind of math ever since reading about submerged submarines in WW2 and CO2 buildup in that environment. I don’t have the cites handy, but I’m really sure it’s the CO2 that kills there, and not depletion of O2. Painful way to go, too.

For real-world numbers, just how sealed is the modern bedroom in a Western home? I mean is there 1 change of air in 8 hours, 1/2 an air change, several air changes? The cited references in the article from Indoor Air I mentioned probably have the answer, but that would involve work.

6

I was recently surprised when I left a lit deodorizing candle burning in my Jeep and returned a few hours later to find the candle no longer burning. I wouldn’t have thought my vehicle was that well sealed.

7

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.

8

You know, I don’t speak math, so I’m not sure I follow the details, but it’s impressive and sexy when others sling the numbers. :wink: (Ooops, was that harassment? Sorry!)
What brought this subject to my mind is how attitudes change over time. My father talked about how his mother insisted that there be an open window in the bedroom each night, regardless of temperature or rain or even a blizzard. He hated it (damned cold) and didn’t impose the rule in his household. And now one of his granddaughters is getting some special sealing plastic layer added to most of the windows in her house. She’s doing it to cut down on heating bills (older, drafty house) but still … I imagine her great grandmother would have a fit if she’d known.

9

I’m pleased that this question got more consideration that the one from the guy who asked here about sleeping in a car :slight_smile: Because I always thought that the response to that question was a little less convincing than the response shown here.

(Sorry, slow internet means searching is painful)

10

People can get quite superstitious about this sort of thing

11

My third post ever on these forums was to ask a similar question! Interestingly, the last poster in that thread speculated that the increase in carbon dioxide would probably kill you before the lack of oxygen.

Nitpick: a psychiatrist is a medical doctor. That would be like saying “Scott is both a medical doctor and a cardiologist.”

If you were placed into totally sealed room with zero oxygen–say, 100% carbon dioxide or 100% nitrogen at standard temperature and pressure–the lack of oxygen would certainly kill you before the buildup of CO2 became appreciable. However, there are conditions, like COPD, that prevent you from getting rid of CO2 fast enough, leading to hypercapnia, or elevated blood CO2 levels. Blood is an aqueous solution, and CO2 in an aqueous solution exists in equilibrium with carbonic acid. So too much CO2 in your blood makes your blood too acidic, a condition called respiratory acidosis, which if untreated can lead to shock, in which your major organs start to shut down, leading to death.

12

Is there any evidence for this other than Scott’s own claims?

13

All psychiatrists are medical doctors. Scott Alexander’s About page does not mention his academic background or license(s), though, just that he is a psychiatrist on the US West Coast.

14

What about the starting level of CO2? You need to add the 288L to the amount of CO2 already in the room when the door shut. I think it might make an appreciable difference.
I think the starting level is 30.6L of CO2?

15

Sorry, didn’t explain it well.

IIRC, in one of his articles he detailed how he first became a general practitioner, discovered he hated it, then returned to school to become a psychiatrist.

16

my husband likes to leave the ventilation system off in our plug in/hybrid car to save electricity (and drive farther before the gas engine fires up). I hate this, and the car feels stuffy to me in about 3-5 minutes. But it must have some passive ventilation as he’s survived long trips without turning it on. :slight_smile:

Carbon dioxide and oxygen are both gases that we need in the right concentration. Carbon dioxide is actually the “need to breathe” trigger. With none of it there’d be a risk of forgetting to take your next breath. A little too much and it feels stuffy and uncomfortable. Much too much can kill you, and (having seen hamsters killed that way) it’s not a nice way to go.

Oxygen is extremely reactive, and too much can oxidize stuff that was supposed to stay the way it was. Preemies with undeveloped lungs are given supplemental oxygen, and i think there used to be a problem with them going blind from it. I’m general, I think too much oxygen can “age” you.

I have a related question: if CO2 levels continue to rise, at what point does “fresh air” start to feel stuffy to us? When do wealthy people start running CO2 removing devices in their living space? When do employers do that to maintain productivity? Might these happen in our lifetime?

17

So I guess the answer to my question is, “No, there is no evidence corroborating Scott Alexander’s claim to be a doctor.” In that case, why are we relying on him as a source of medical knowledge for this thread?

18

Last weekend I toured a WWII era sub. If I remember what the tour guide said, they ran low on oxygen before electricity. There were compressed O2 tanks throughout the vessel in case they needed to stay down past about 30 hours. Otherwise they surfaced nightly if possible. I don’t know the ship volume but that divided among 85 or so people for 30 hours would be a start.

19

True, I did forget that. No idea what normal ambient CO2 concentration, so we’ll use your volume. Which should bump things by about 10 percent, and put the final concentration over the 8hr TWA. Not in violation, since the 8hr TWA for our simple model should be half of that, but again, we’d probably notice it: ‘Is it getting stuffy in here?’

20

Depends on how energetic they were getting with the props. I want to say a flank bell submerged will drain the batteries from full in 90 minutes or so. Then again, the speed difference between flank and 1/3 or 2/3 might be the difference between making it away from the destructive radius of the depth charge or not…

I want to say I remember crews opening cans of CO2 absorbant to increase submerged time.