Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance

What the study found

Decision-making scores declined at higher CO2 exposures in several domains, with larger effects at 2500 ppm.

Limitations

Small sample; unusually strong effects have not been reproduced uniformly; exposure interpretation remains debated.

Neurodesign interpretation

This paper is useful because it forced the field to ask whether occupant-generated CO2 is only a ventilation marker or can also act directly. Neurodesign should preserve that uncertainty.

Possible design implications

Prioritize ventilation and source control in cognitively demanding rooms, especially high-density meeting and learning spaces.

Why it stays in the corpus

Retain as the canonical direct-CO2 experiment and pair it with later meta-analyses.

Study design

Repeated controlled exposures at 600, 1000 and 2500 ppm

Population

22 adult participants

Setting

Controlled exposure chamber

Field

Indoor air quality

Mechanism

Decision-making under elevated CO2

Spatial variable

Indoor CO2

Keywords

CO2, decision making, ventilation, controlled exposure