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Comment by justworkout | Hacker News Reader

https://www.hsph.harvard.edu/healthybuildings/2021/09/09/imp...

CO2 affects cognition all around.

We also found effects of CO2 (a proxy for ventilation) on cognitive function. For every 500ppm increase, we saw response times 1.4-1.8% slower, and 2.1-2.4% lower throughput.

Which is why you open a window: Atmospheric CO2 is at around 410ppm. And rising, yes, by around 2-3ppm/a. So I suppose it's making us around 0.02% slower per year, going by those figures.

We need to curtail emissions, but not because atmospheric CO2 is affecting cognition.

So, assuming a straight line backwards, we have gotten 1% slower since 1970?

Doesn't sound great.

Edit: to prove my slowness I typo'd a zero into the number. It's 1%, not 10%.

It's not a straight line, no. In 1970 it was around 320ppm, so not quite 100ppm less than today as opposed to 100-150ppm. So 0.3% slower, again if you take those performance numbers at face value which you probably should both, because they are the result of experiments that take place at levels of 1000ppm and beyond and it's unclear if they even apply to lower levels.

https://www.statista.com/statistics/1091926/atmospheric-conc...

Today’s 422ppm (https://www.co2.earth/daily-co2) assumes you’re outside in a remote area with a light breeze to constantly get fresh air. Even just a city has higher levels and normal office space is sitting at 800ppm or so. A meeting room can break 1500ppm depending on occupants and ventilation, which is one of the reasons meetings suck and packed meetings suck more.

Thus a meeting where the PPM was ~1200ppm in 1970 with the same number of people in the same room in 2023 should be ~1300ppm.

Yeah, we're talking atmospheric CO2, hence: outside. I'm aware that indoor CO2 is higher, I've quoted the study.

I was pointing out that outdoor CO2 ppm vary significantly, and we are at ~420ppm not 410ppm which was quoted earlier.

Also, outdoor ppm increases indoor ppm which is within the range being studied so talking about cognitive decline from ongoing carbon emissions is supported.

Counterpoint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/ina.12939

> Impairment of cognitive performance is not expected from exposure to 20 000 ppm CO2, neither as direct effect on central nervous system function nor as a distraction related to perception of health effects.

The study you’re linking is discussing the combined effects of CO2 and PM2.5; likely it’s the particulate matter that’s the issue rather than the CO2.

CO2 is generally used as a proxy for IAQ as in the link you posted. I strongly suspect it's another factor than just CO2, for example reduced O2 levels, or VOCs and particulates. I'm sceptical that usual levels of CO2 have a noticeable impact on metabolism.

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