Indoor air quality during sleep under different ventilation patterns

Sleep plays a crucial role in the human welfare. This preliminary study aimed to characterise the indoor air quality (IAQ) during sleep, which has been scarcely studied, to better understand the occupant's exposure. Comfort parameters along with indoor air pollutants were assessed in one bedroom during the sleeping period of the occupant. Four scenarios of natural ventilation in the bedroom were studied regarding IAQ. The ventilation setting with door and window closed (CDCW) promoted the lowest air change rate (0.67 ± 0.28 h−1) and the highest levels of carbon dioxide (CO2), carbon monoxide (CO) and volatile organic compounds (VOCs). Irrespective of ventilation condition, particulate matter levels (PM10, PM2.5) were always high, although maximum values were recorded under CDCW. The simultaneous opening of door and window supplied the highest air change rate (4.85 ± 0.57 h−1). Several pollutants were found to be in concentrations above the established Portuguese guideline for assuring IAQ, namely VOCs, formaldehyde and PM2.5, in specific ventilation settings.