Impact of CO₂ concentration on Elderly residential by EEG & ECG

¹ Department of Interior Design, National Taichung University of Science and Technology, Taichung City, Taiwan
² Department of Interior Design, Shu-Te University, Kaohsiung City, Taiwan
³ Departments of Neurology and Occupational Medicine, Chi Mei Medical Center, Tainan City, Taiwan

Abstract

Abstract. This study investigates the impact of combined indoor environmental conditions, specifically carbon dioxide (CO₂) concentration, and ventilation states, on the psychophysiological responses of elderly and young populations. A controlled experimental design was adopted to measure electroencephalography (EEG) and electrocardiography (ECG) indicators alongside subjective environmental assessments. Participants were categorized into healthy elderly and young adult groups to examine age-related physiological differences. The results indicate that healthy elderly participants exhibited greater neurophysiological sensitivity to elevated CO2 and combined environmental stressors, as reflected by altered EEG band activity (e.g., increased theta and beta bands, and decreased alpha band). In contrast, young adults demonstrated comparatively stable physiological responses across similar environmental conditions. Notably, while subjective perceptions of the environment remained largely neutral or acceptable among the elderly, objective EEG measurements indicated increased neurophysiological load. These findings highlight the limitations of relying solely on subjective perception for indoor environmental evaluations in aging populations and demonstrate the critical value of integrating objective psychophysiological indicators. The results provide empirical support for developing health-oriented residential ventilation strategies tailored to older adults.