2260 ppm
poor ventilation pushed CO₂ to more than four times the high-ventilation level
Low ventilation caused CO2 to rise to 2260 ppm
In Condition B, representing a poorly ventilated open-plan office scenario, the outdoor air flow rate was only 2.3 l/s per person. This led to a CO2 concentration of 2260 ppm, primarily driven by bioeffluents from occupants. CO2 was used as the main indicator of bioeffluent accumulation and overall air quality degradation.
In Condition A, outdoor air flow rate of 28.2 l/s person (CO2 level 540 ppm) was applied and in Condition B, outdoor air flow rate was 2.3 l/s person (CO2 level 2260 ppm).
Related findings
drivers reported higher mental effort at 1800 ppm CO₂ than at 800 ppm
Moderate CO2 elevation (1800 ppm) increases perceived effort in drivers compared to lower CO2 (800 ppm)
Chao Wang et al., 2023, The Science of The Total Environment
bioeffluents at high CO2 reduced cognitive performance on a cue-utilization test
Bioeffluent exposure at 3000 ppm CO2 reduced performance on a cue-utilization cognitive test
X. Zhang et al., 2017, Indoor Air
bioeffluents at high CO2 significantly raised salivary α-amylase, a stress marker
Bioeffluent exposure at 3000 ppm CO2 significantly increased salivary α-amylase compared with pre-exposure levels
X. Zhang et al., 2017, Indoor Air
Read more in
Workplace 
Workplace What your office costs
Four design variables that move cognitive performance and who pays for them
Healthcare More from The Built Review
Workplace Pricing biophilia: what the evidence is worth
Read at the primary sources, the business case for nature in buildings is narrower than advertised and strong enough to act on.
Healthcare Built to Wake: How Hospital Noise and Light Undermine Patient Sleep
Of the two environmental levers on inpatient sleep, noise control is the better proven and the cheaper, while tunable lighting for the general ward is the one the evidence does not yet support.
Workplace Germany's missing indoor-air bill
France, Britain and Australia have priced bad indoor air. Germany's missing number is a political choice, not a methodological limit.