I've started questioning this premise given that concentration of CO2 in the lungs (while resting) never falls below 10000ppm (I'm possibly underestimating this number).
Though I'm not excluding the possibility that indoor CO2 concentration strongly correlates with cognitive underperformance, which may be caused by other compounds emitted by human body.
Though I'm not excluding the possibility that indoor CO2 concentration strongly correlates with cognitive underperformance, which may be caused by other compounds emitted by human body.