CO2 concentrations

Sleep is essential for overall health and well-being. The quality and efficiency of sleep are strongly influenced by the sleep environment, including indoor air quality. This study investigates the influence of mechanical ventilation on bedroom air quality during sleep and its impact on sleep efficiency and quality. Objective and subjective measurements were conducted to assess the effects of operating a mechanical ventilation system.

The predicted and measured carbon dioxide (CO2) emitted by human respiration into an occupied space has been used as an indicator for controlling buildings' ventilation rates. However, this application assumes a constant emission rate for the entire population. Conversely, new knowledge has shown that this variable depends on the number of people in the room and their sex, diet, height, and above all, body mass and metabolic rate.

The steady-state concentration of occupant generated carbon dioxide (CO2) is used in some applications as an indicator of compliance with a required ventilation rate. These applications assume that the CO2 is at a uniform concentration in the space being considered, and that the outdoor concentration, ventilation rate, and CO2 emission rate are all constant. Emission rates are often derived using an equation in the ASHRAE Fundamentals Handbook, which is poorly referenced and not based on the most recent understanding of the principles of human metabolism.