Abstract
This article presents the results of a study to assess the quality of air (the presence in it of the amount of fine dust, carbon monoxide and carbon dioxide CO, CO2) in an enclosed space. The experiments were carried out on the platforms of metro stations with different designs during normal operation of artificial tunnel ventilation and when the daytime tunnel ventilation systems were turned off. The results show that the concentration of fine dust varies greatly depending on the type of ventilation and plant design. The air quality on narrow platforms served by single-track tunnels is highly dependent on the forced ventilation capacity and cannot rely solely on the piston effect of the train to reduce the concentration of fine dust on the platform. In contrast, the fine dust level in stations with spacious double-track tunnels does not change much when the tunnel ventilation is turned off, which allows significant energy savings without compromising air quality. The CO concentration on the platform is very low (≤1 ppm) due to the ingress of external polluted air from the open street space. Average CO2 values range from 371 to 569 ppm, depending on train congestion and frequency. Keywords: underground, tunnel ventilation, piston effect, particulate matter, carbon dioxide (СО2), carbon monoxide (СО).