Vinder af P.O. Fangers Legat Glædelig jul og godt nytår Fotos: Michael Barrett Boesen. Bedroom Ventilation and Sleep Quality By Xiaojun Fan (Ph.D. candidate) and Pawel Wargocki (Assoc. Prof., supervisor), International Centre for Indoor Environment and Energy (ICIEE), Department of Civil Engineering (BYG), Technical University of Denmark (DTU), Kongens Lyngby, Denmark Sleep is essential for restoration, recovery, health, and the next-day performance. The present Ph.D. project explores the ef- fects of bedroom ventilation on sleep quality. This article briefly introduces the completed and planned experiments and the preliminary results. Why sleep? We usually sleep 7 to 9 hours a day which corresponds to ca. one-third of our life (more than 20 years on average). Research has documented that good sleep can boost immune functions [1], reduce the risk of cardiovascular diseases [2], obesity [2,3] and diabetes [4], consolidate memory [5], and improve our well-being and the next- day work performance [6]. Why bedroom ventilation? Research focusing on bedroom environ- ments has been growing over the last years and shows that thermal [7,8], acous- tic [9], and visual environment [10] im- pact sleep quality. However, very few studies explored the effects of ventilation on bedroom air quality and sleep quality [11]. Most of the research on ventilation effects on humans has focused on offices and schools, much less on dwellings, par- ticularly bedrooms. Bedrooms are unique since we remain immobile (sleeping) for extended periods and have lower activity levels than awake people [12]. We are con- sequently exposed to pollutants for much longer than in other indoor environ- ments. Present Ph.D. project The present Ph.D. project intends to fill the gap in our understanding of the ef- fects of ventilation on air quality in bed- Preliminary results indicate that 44% of participants slept with the door and window closed and that ventilation in most bedrooms did not meet the minimum ventilation requirement in the Danish Building Regulation. rooms and, subsequently, sleep quality and next-day work performance. The project includes the following activities: • A systematic literature review on bed- room ventilation and sleep quality to shed light on the “typical” bedroom ventilation. The review also includes a summary of regulations and standards on bedroom ventilation. • An online survey to identify the types of ventilation systems in actual bed- rooms and the factors influencing bed- room air quality and disturbing sleep quality. • The measurements of CO 2 emission rates from sleeping people to enable the estimation of ventilation rates in bed- rooms based on the measurements of CO 2 concentrations. • A laboratory study to investigate the ef- fects of ventilation and temperature on sleep quality. • A cross-sectional field study to measure ventilation rates in actual bedrooms and examine how they affect sleep quality. • An intervention study to examine how changing bedroom ventilation affects sleep quality and to develop the rela- tionship between sleep quality and bed- room ventilation. Findings from the Ph.D. project so far Review of the bedroom ventilation requirements We found that there is general guidance towards the provision of ventilation in the design of residential buildings from two international standards and fifteen national-based standards. However, only a few among them specifically prescribe ventilation requirements for bedrooms. Ventilation in bedrooms is merely the result of ventilation prescription for the entire dwellings. Taking Danish Building Regulation (BR) as an example, the BR prescribed a ventilation rate for the en- tire dwelling to be at least 0.5 h-1 since 1982. It was revised and now prescribes the ventilation rate of 0.3 L/s per m2 heated floor area. There is also no inter- nationally accepted and standardized method based on which the ventilation requirements in bedrooms can be speci- fied. 18 HVAC 13 · 2021
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