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 (CO2) due to exhalation. Although CO2 is not considered to pose serious health risks to occupants, elevated levels of CO2 may serve as an indicator of insufficient ventilation. This study examines how CO2 is distributed within a complex indoor environment of a classroom and how this distribution is affected by different parameters. Measuring CO2 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 CO2 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 CO2 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 CO2 monitoring purposes. © 2013 The Author(s).