[zik]

Higher levels of CO2 impair cognitive function [1].

In fact there's no floor - even small increases in CO2 have small but measurable effects.

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

[aulin]

Sure, point is we as humans are already equiped with efficient ways to detect it. Only home use I can imagine is to drive some ventilation automation.