Study on the relationship between the CO2 concentration and pedestrian flow in a building evacuation passageway

Abstract

People ubiquitously produce CO2. The quantitative relationship between the CO2 concentration and pedestrian flow needs to be determined if the CO2 concentration is to be used to reflect pedestrian flow. Therefore, a field test was carried out to measure the CO2 concentration and pedestrian flow in an evacuation passageway of a densely populated building. The results show that the variation in the CO2 concentration always lags behind the variation in the pedestrian parameters. When pedestrians enter a building evacuation passageway over a long time span with high randomness, the quantitative relationships between the pedestrian density and CO2 concentration and between the pedestrian flow rate and CO2 concentration are not clear. When all the people in the building are required to leave at the same time, the relationships between the pedestrian density and CO2 concentration and between the pedestrian flow rate and CO2 concentration can be described quantitatively. The CO2 concentration can be taken as an early warning index to manage pedestrians in evacuation passageways of densely populated buildings. Two possible methods are provided to help provide early warnings in pedestrian management. These results are expected to provide new ideas for pedestrian statistics and pedestrian flow management in densely populated buildings.