alt Hacker News> CO2 levels are locally elevated in the area where you exhale.
That's the same area we inhale from... Wouldn't be right to measure there then? It's not like we're interested in the amount of CO2 on the ground (in this discussion)
> CO2 levels are locally elevated in the area where you exhale.
That's the same area we inhale from... Wouldn't be right to measure there then? It's not like we're interested in the amount of CO2 on the ground (in this discussion)
No, because the studies that establish the levels correlated with cognitive changes use ambient CO2 levels. Not with a stream of air directed, maybe, from your nose to your wrist.
It is not possible to come up with a different baseline for wrist-worn monitors because the measurements could change significantly based on even small factors like the position of the wrist or smartphone.