CO₂ emission rates from humans when sleeping and awake. Impact of environmental factors and age

We summarize our three recent studies that determined CO₂ emission rates from humans using the mass-balance model and the measured steady-state CO₂ concentration. One study determined CO₂ emission rates from sleeping adults; they were on average 11 L/h/person, 30-45% than for awake people at a light activity. They were relatively stable and similar to the published work and estimations using models. Two studies determined CO₂ emission rates from the sedentary awake people at a light activity; they were on average 12.9-17.8 L/h/person. They were not significantly different between teenagers, young adults, and the elderly, nor when ozone and relative humidity increased. Reduced ventilation and increased CO₂ significantly reduced CO₂ emission rates; the changes in respiration could be the plausible reason. CO₂ emission rates increased at thermal sensation departing from neutrality; increased metabolic activity could be the plausible reason. The emission rates were different from published results and estimations using models.