Physiological Responses to Different CO₂ Levels in Poor Ventilation Room

Abstract

According to ventilation of acceptable indoor air quality (IAQ), the air carbon dioxide concentration (C_CO2) and air temperature (T_a) increase with human in poor ventilation. The main source of CO₂ pollution indoor is human respiration. This study simulates a poor ventilation condition and 10 volunteers participate with non-mask method to study the physiological responses in three C_CO2 levels. Facial temperature (T_f), saturation of percentage oxygen (SpO₂), and electrocardiography (HR) were spontaneously acquired while subjects were inside an airtight room. Analytical results indicate SpO₂ decreased as C_CO2 increased. Those results further demonstrate a positive correlation between C_CO2/HR and C_CO2/T_f, implying that the central-chemoreflex can stimulate the respiratory system since SpO₂ variance and increased HR can promote pulmonary gas exchange. Notably, temperature difference in T_f and T_a increased under low C_CO2 and then reversed and stabilized inference the antagonistic pattern accelerated rapidly initially and decelerated finally stabilized. These findings also imply that the internal body responded to changes in the external environment rapidly, attempted to homeostasis, and reached equilibrium slowly. Variations of C_CO2 and T_a can be modeled by equations. Results of this study prove that IAQ affects physiological responses in the symbiotic relationship between the human body and surrounding environment.