Previous work at the Institute has identified inadequate fresh air entry as a serious concern in office buildings. This problem is present in ventilation systems in which, for economic reasons, fresh air entry is regulated as a function of outside temperature rather than density of occupation. Carbon dioxide levels are generally accepted to be good indicators of density and ventilation system efficiency. This project examined the impact of a CO2-based monitoring system on air quality. The study was conducted on two floors of an office building, one supplied by a CO2-controlled ventilation system, the other by a conventional temperature-based ventilation system. However, in order to ensure the comfort of building occupants, it proved necessary to install a secondary temperature control on the floor supplied by the CO2-based ventilation system. There were no differences in contaminant levels, comfort levels, or ventilation parameters between the two floors. The project demonstrated the difficulty associated with the implementation of fresh-air inlet systems based solely on the levels of ambient CO2.
