The spatial distribution of carbon dioxide in rooms with particular application to classrooms

Abstract

In most buildings, occupants are the main source of indoor carbon dioxide (CO 2 ) due to exhalation. Although CO 2 is not considered to pose serious health risks to occupants, elevated levels of CO 2 may serve as an indicator of insufficient ventilation. This study examines how CO 2 is distributed within a complex indoor environment of a classroom and how this distribution is affected by different parameters. Measuring CO 2 concentrations at a single location or height may not act as a true representation of an entire space, unless it is measured in a very small confined space. In this study, it was observed that higher CO 2 concentration values can be found at higher levels in a room and not only at a height between 1 m and 1.2 m as claimed by many researchers. Therefore, if CO 2 concentration levels vary significantly, deviations from the average measured values could become large. It was also found that the CO 2 concentration reflects the dynamic relationship among the occupants, their activity levels and occupancy periods. The findings present a useful contribution for future researchers to efficiently and strategically design experimental set ups with well-organised positioning of sensors for CO 2 monitoring purposes.