Key ideas
Core concepts
- Elevated CO₂ levels in classrooms reduce decision-making and cognitive function; Satish et al. (2012) found performance reductions at moderate concentrations.
- Proper ventilation and air quality monitoring keep CO₂ within acceptable limits for learning.
Carbon Dioxide Impact: Elevated CO₂ levels in classrooms can impair cognitive performance by reducing oxygen availability to the brain, affecting students’ ability to think and learn effectively.
Connected to
Cognitive Load Theory | Attention | Temperature | Sleep
Research evidence
Moderately elevated CO₂ levels reduce decision-making performance according to controlled studies (Satish et al., 2012). These effects occur not at extreme levels, but at concentrations commonly found in poorly ventilated classrooms. At 1,000 ppm, cognitive performance shows measurable reduction (Allen et al., 2016). At 2,500 ppm, negative effects become more pronounced (Satish et al., 2012).
Physiological mechanism
Elevated CO₂ levels can lead to hypoxia, where insufficient oxygen reaches the brain and impairs neural function. The resulting cognitive impairment affects decision-making, concentration, learning capacity, and memory formation.
Proper ventilation reduces CO₂ concentration, which improves students’ cognitive function and learning outcomes (Wargocki & Wyon, 2017; Haverinen-Shaughnessy et al., 2011, 2015; Bakó-Biró et al., 2012). Schools should regularly monitor indoor air quality, including CO₂ levels, to ensure they remain within acceptable limits.
References
Satish, U., Mendell, M. J., Shekhar, K., Hotchi, T., Sullivan, D., Streufert, S., & Fisk, W. J. (2012). Is CO₂ an indoor pollutant? Direct effects of low-to-moderate CO₂ concentrations on human decision-making performance. Environmental Health Perspectives, 120(12), 1671-1677. https://doi.org/10.1289/ehp.1104789
Allen, J. G., MacNaughton, P., Satish, U., Santanam, S., Vallarino, J., & Spengler, J. D. (2016). Associations of cognitive function scores with carbon dioxide, ventilation, and volatile organic compound exposures in office workers: A controlled exposure study of green and conventional office environments. Environmental Health Perspectives, 124(6), 805-812. https://doi.org/10.1289/ehp.1510037
Wargocki, P., & Wyon, D. P. (2017). Ten questions concerning thermal and indoor air quality effects on the performance of office work and schoolwork. Building and Environment, 112, 359-366. https://doi.org/10.1016/j.buildenv.2016.11.020
Haverinen-Shaughnessy, U., Moschandreas, D. J., & Shaughnessy, R. J. (2011). Association between substandard classroom ventilation rates and students’ academic achievement. Indoor Air, 21(2), 121-131. https://doi.org/10.1111/j.1600-0668.2010.00686.x
Haverinen-Shaughnessy, U., & Shaughnessy, R. J. (2015). Effects of classroom ventilation rate and temperature on students’ test scores. PLoS ONE, 10(8), e0136165. https://doi.org/10.1371/journal.pone.0136165
Bakó-Biró, Z., Clements-Croome, D. J., Kochhar, N., Awbi, H. B., & Williams, M. J. (2012). Ventilation rates in schools and pupils’ performance. Building and Environment, 48, 215-223. https://doi.org/10.1016/j.buildenv.2011.08.018