CO2-curious

Does it give you headaches? Or is it just a correlate?

CO2, in the act of murdering people

CO2 trying to kill office workers

I became aware of indoor CO2 maybe 5-8 years ago. At the time I worked in a large, open-plan office. I noticed that I would start feeling dizzy many afternoons. The office had these CO2 monitors installed on many walls, and my dizziness tended to correlate with high CO2 levels.

“High” CO2 in this case was over 1,500ppm. I believe the monitors in that office would call <1,000ppm “low” and everything in between these 2 numbers was “normal.”

I also noticed that I’d wake up some days with a slight headache, and it would quickly go away after opening the window. If I cracked the window overnight, or had the A/C running, I wouldn’t get this headache.

I concluded that high CO2 concentration must be giving me headaches.

Two or three years ago I even purchased a CO2 monitor of my own and kept it on my desk or nightstand.

Again, the correlation would appear: I would feel stuffy or dizzy once the CO2 got much over 1,500ppm. I felt really well and invigorated if it was substantially below 1,000ppm.

For the record, the outside world is currently about 420-480ppm, depending on where you are located. I took my sensor outside for a walk, and it dutifully showed something like 450ppm.

CO2 did obesity & submarines?

I remember reading Slime Mold Time Mold’s A Chemical Hunger, and there being a brief aside about CO2: one of their “Mysteries of Obesity” was the fact that altitude seemed somewhat protective of obesity. If you looked at a map of obesity by county in the U.S., you could clearly see the altitude. Colorado is the leanest state, and it’s largely covered in giant mountains.

One leading theory was the CO2, lower at altitude. Yet, SM TM observed, the submarines in the U.S. Navy often run CO2 numbers 10x higher than normal in their atmospheres, and they did not notice any obesogenic effects from that.

And, presumably, the sailors on those submarines don’t walk around with splitting headaches all day, despite experiencing 10x the amount of CO2 that normal people would in offices.

I remember wondering about this; how could these sailors possibly exist in 10x the CO2 when the CO2 in an office gave me headaches at only 1,500ppm?

old creaky house, includes free CO2 mystery

This Old House

Then, over the holidays, I visited my family’s home - and I brought my CO2 monitor. Why not, it’s a small enough battery-powered device. Wouldn’t it be fun to find out?

Turns out, the CO2 in my small guest room was sky high. I’m talking at least 3,000ppm overnight.

Yet no headaches.

A few times I even reached over 4,000ppm, with my record level being about 4,800ppm, almost 5k!

Yet even the 4,800ppm didn’t give me a real headache. Maybe the beginning of a “stuffy” feeling at best.

Was my monitor miscalibrated? No, when I aired out the room, the CO2 level quickly went down to the 450ppm level again. Yet due to the small size of my guest room, it was rarely <1,500ppm for long when I was in the room at all.

What was going on?

I can only conclude that CO2 was never the culprit, but merely correlated with something else that gave me headaches. Carbon monoxide maybe, or low oxygen.

I suspect that the actual causal factor correlates tightly with CO2 in a certain ratio in modern buildings with modern insulation. Modern building codes mandate vapor barriers and pretty tight insulation.

The old, creaky house I grew up in has none of these things. You can feel the cold seeping in through the cracks & walls (the walls are largely made of cracks, lol. It’s sort of a the-more-cheese-the-less-cheese situation).

I would presumably eventually get a headache even in this house. But I suspect that the permeability of the walls drastically changed the ratio by which CO2 correlated to whatever was causing the headaches.

Instead of 1,500ppm practically guaranteeing a headache, I was pretty much guaranteed headache-free until at least 4,000ppm here.

Maybe that means the old house has higher permeability for whatever causes headaches than for CO2? Does that mean it’s a smaller particle that isn’t as easily trapped, despite the old house trapping CO2 just fine?

I’m not sure.

CO2 did nothing wrong?

In any case, I’m pretty convinced that CO2 did nothing wrong here, and that I “learned” a correlation between it and headaches from that office sensor almost a decade ago, which was never causal.

I’m not a big fan of modern building codes anyway. I’d rather pay a little extra for more heating and not suffocate, living inside a giant plastic bag. But nobody’s asking me, lol.

Not sure my little CO2 monitor is of any use now. I suppose I can still use it to learn the correlation between CO2 and headaches wherever I go, and just be aware that this ratio depends on the place & insulation there.

Just something curious. Shows you how something as obvious and easy to measure (and in multiple places!) can still be wrong if you’ve never stepped outside of a certain context in which it happens to be true.

There are, of course, countless analogies in the diet world. The first one that comes to mind for me is LDL: LDL correlates with “bad” if you squint very hard and don’t ask any questions.

But if you’re even the slightest bit curious, the mechanisms and correlation falls apart immediately.

I guess what I’m saying is: let’s acknowledge mysteries.