• The nocturnal CO₂ emission rate for young Chinese adults was 10.1 ± 2.4 L/h. • Ventilation conditions significantly affected nocturnal CER. • Male participants exhibited higher CER than females during sleep. • Sleep CERs in young Chinese adults differ from certain standard-based estimates. The carbon dioxide emission rate ( CER ) during sleep is a key parameter for assessment of nocturnal metabolism and estimation of ventilation rate. But the CER during sleep remains insufficiently characterized, particularly in young Chinese adults. In this study, multi-night sleep experiments were conducted with 36 young Chinese adults (18 – 33 years) under three ventilation conditions (V1, V2, V3), maintaining approximate average overnight CO₂ levels of 750, 1000, and 1300 ppm, respectively, with indoor air temperature maintained at 20 °C and relative humidity controlled at 40–60%. CER was estimated using the CO₂ mass balance model, and its robustness was verified through internal consistency check, sensitivity and uncertainty analyses. The average CER was 10.1 ± 2.4 L/h, with males exhibiting 15% higher values than females, reflecting sex-based metabolic differences. Ventilation conditions significantly affected CER during sleep, with mean values of 11.4 L/h under V1, 8.8 L/h under V2, and 10.2 L/h under V3. This study demonstrates that sleep CER is not only population-specific but also environment-dependent.
Xiang et al. (Fri,) studied this question.