Impact of experimentally elevated CO₂ concentrations and temperature on cognitive function: An EEG-based study under...

Area of Science:

• Environmental Science
• Cognitive Neuroscience
• Building Science

Background:

• Global warming is projected to change indoor thermal conditions and air quality.
• The impact of these changes on human learning and cognitive function is not well understood.
• Existing research often fails to isolate the effects of elevated CO₂ and temperature from general poor ventilation.

Purpose of the Study:

• To investigate the combined effects of elevated indoor carbon dioxide (CO₂) concentrations and temperature on cognitive performance and well-being.
• To differentiate the impacts of specific environmental factors (CO₂ and temperature) from general ventilation quality.
• To develop a deep learning-based Cognitive Comfort Model (CCM) using electroencephalography (EEG) data.

Main Methods:

• A climate chamber study with 24 participants.
• Experimentally manipulated indoor CO₂ levels (500 and 5000 ppm) and temperatures (22 °C and 28 °C).
• Participants completed neuropsychological tasks, subjective evaluations, physiological measurements, and EEG recordings.

Main Results:

• Significant interactions between CO₂ levels and temperature were found for subjective comfort (noise acceptability, thermal comfort).
• EEG data revealed significant changes in alpha, theta, and delta brainwave power under combined thermal-CO₂ stress.
• Behavioral task performance showed minimal changes, indicating preserved overt cognitive function despite physiological and subjective alterations.

Conclusions:

• Combined exposure to elevated CO₂ and temperature can negatively affect subjective comfort and neural indicators of cognitive load.
• These environmental stressors can modulate cognitive load even when observable task performance remains unaffected.
• Findings support the development of refined indoor environmental control strategies to maintain cognitive well-being in warming climates.