Measurement of occupants' stress based on electroencephalograms (EEG) in twelve combined environments

•We conducted a chamber study to examine the effects of indoor environment on stress.•Stress was maximized with a temperature of 30 °C, air pollutants, and noises.•The α wave in the frontal lobe is useful for assessing a non-stressful environment.•The high β wave in the temporal lobe is useful for assessing a stressful environment.•There is a visual usefulness of the brain map analysis.

This study examines the effects of indoor environment on stress levels. Temperature, odor irritants, and sound were selected as environmental elements to be studied within the combined environment, and these were individually controlled in a total of 12 combined environments with established climate chambers. The occupants' stress was measured using paper-based tests, and the two combined environments that showed the most different stress aspects were determined based on their results. A second test was then performed using an electroencephalogram (EEG), and in this test, occupants' stress in the two combined environments were compared using an EEG analysis to generate a brain map showing occupants' stress states from a physiological perspective. Experimental results indicate that occupants' stress was maximized when they were exposed to a temperature of 30 °C, odor irritants (VOCs) and to road traffic noises. In this stressful environment, it is presumed that the differences in brain mapping of the relative high-beta wave in the temporal lobe can be useful when assessing participants' stress.