Indoor air quality during sleep in university dormitories: exploring the impact of various ventilation patterns

The quality of sleep is significantly important for human health. However, the importance of air quality during sleep, particularly, in high-density residential settings, such as dormitories, has been insufficiently addressed. This study aims to assess the coupled effect of ventilation modes and air change rate (ACH) on indoor air quality (IAQ) within sleeping environments in university dormitories and to identify effective ventilation patterns to fill the research gap. To comprehensively examine their combined effects on the sleep environment, several representative dormitories at a northern Chinese university were evaluated during winter. The concentration variation of indoor pollutants in the sleep environment under natural ventilation conditions was monitored, revealing that the indoor air quality significantly deteriorated during sleep. Furthermore, a numerical model was developed to study the effect of different mechanical ventilation patterns on the improvement of sleep microenvironment. The results indicated that the local air supply system with ACH = 2 was identified as providing superior air quality, successfully addressing the limitations of the ceiling air supply system and upper air supply system. We successfully investigated the coupled effects of ventilation mode and ACH on sleep IAQ, which can provide a theoretical basis and guidance for the study of a complete sleep IAQ improvement program. Further studies show that bed curtains can affect the distribution characteristics of indoor pollutants, and the design of ventilation system should focus on the influence of bed curtains on air flow organization in future research.