Health-demand ventilation control strategy in northern Chinese homes : how much ventilation do we need to protect occupants’ health

Introduction: Indoor air quality in dwellings has particular importance regarding occupants’ health. Ventilation is an important means to improve indoor air quality and guarantee occupants’ health. Methods: We utilized CO₂ produced by occupants to measure air exchange rate (i.e., the volumetric out-to-indoor airflow rate divided by building volume, h⁻¹) in Chinese homes, which were then linked to health outcomes like asthma and sick building syndrome symptom. Finally, we proposed a “health-demand” ventilation control strategy according to the relationship between air exchange rate and health outcomes. Results and Discussion: Each 0.1 h⁻¹ increase in air exchange rate at night was associated with adjusted odds ratios of 0.97 (Confidence Interval (CI): 0.94–1.00) for rhinitis among children and 0.95 (95% CI: 0.91–0.98) for mucosal sick building symptom among adults. Finally, we proposed a “health-demand” ventilation control strategy according to the relationship between air exchange rate and health outcomes. Air exchange rate of 2.5 h⁻¹ and 6.5 h⁻¹ was suggested to deal with sick building syndrome symptoms among adults and rhinitis symptoms among children, respectively.