Is CO2 an indoor pollutant? Direct effects of low-to-moderate CO2 concentrations on human decision-making performance

Key findings from Satish et al. (2012) reveal that even moderate increases in indoor CO₂ (1,000–2,500 ppm) can significantly reduce performance on several cognitive tasks, with effects ranging from diminished initiative and strategic thinking to impaired information usage. Notably, these impacts occur independently of other indoor pollutants, challenging the long-held assumption that CO₂ is merely a proxy for poor ventilation or other contaminants.

Healthy Indoors reinforce the importance of monitoring indoor CO₂. Elevated levels are linked not only to cognitive decline but also to headaches, fatigue, and general discomfort. Modern energy-efficient buildings, while reducing heat loss, often exacerbate CO₂ buildup due to tighter seals and reduced air exchange. This underscores the need for balanced ventilation strategies that safeguard both energy efficiency and occupant well-being.

In summary, the evidence suggests that CO₂ should be considered an indoor pollutant with direct effects on human health and performance. As we strive for sustainable building practices, it is essential to recognize the hidden costs of inadequate ventilation and prioritize indoor air quality as a cornerstone of healthy, productive environments.