Predictive modelling of the effect of fresh air rate on dynamic variation of CO_2 in the waiting room of a railway station

摘要

This paper reports the investigation of the relationship between CO_2 concentration and passenger quantity in the waiting room of a railway station. In situ survey was conducted to collect data on purchased passenger tickets, train schedule and arrival times at Changsha railway station and to establish modelling results. The predictive model is based on the established passenger flow pattern and dynamic governing equations of CO_2 concentration as a reference indicator of indoor air quality (IAQ) in the waiting room at the railway station. This work indicates that the CO_2 source is associated with train passengers, and the air change rates of natural and mechanical ventilation are predominant factors that govern the indoor CO_2 concentration in the waiting room. In addition, the air change rate of natural ventilation ranging from 0.3 h~(-1) to 0.8 h~(-1) would not meet the IAQ requirement in most conditions, whereas the air change rate of mechanical ventilation of n = 2 h~(-1) can meet the IAQ requirement in various situations.