Research on the Preferred Illuminance in Office Environments Based on EEG

The quality of the indoor light environment in buildings directly influences the emotional state, health condition, and work efficiency of people. The application of EEG to indoor light environments is beneficial to further reveal the neural mechanisms of light comfort. In this study, the absolute power of spontaneous EEG was calculated as an objective physiological index, and its trend with the illuminance level of the task area was analyzed. Then, the absolute power of the band, which has the strongest correlation with subjective evaluation and task performance, was selected as the characteristic value. The subjective and objective parameters were validated to explore the preferred illuminance choices for subjects’ comfort and efficiency during the rest stage and the task stage, respectively. The results showed that the power of the δ band and β band at partial channels in the parietal region had statistically significant differences under five illuminance levels in the resting state. The total logarithmic power of EEG and the logarithmic power of the δ band at the Cz channel were negatively correlated with the subjective evaluation. The total logarithmic power of EEG was relatively low when the subjective evaluation was comfortable. There was no statistical difference in the total EEG logarithmic power among the five illuminance levels in the task state, but the subjects had the highest performance indicator and the best cognitive task performance at 500 lux and 750 lux conditions. This research may provide a design reference for the selection of task area illuminance levels for staff during high-intensity mental work and rest.