Experimental study of particle concentrations in an underground Magenta metro station of Paris

Two experiments were carried out in an underground station of Paris. The aim was to evaluate the influence of two parameters on particle number concentrations: ventilation and the movement of trains (braking and departing). These experiments took place by night when traffic stopped to allow the study of all the three parameters individually. Different measurements have been performed: particle number concentrations, air velocity, CO2 concentration and particle mass concentration (PM10).First results do not show any influence of ventilation when turned off and on during one night. Passengers' activity and especially trains pass-by have a stronger influence on particle concentration. Due to the fact that fine particle concentration levels are not reproducible, results should be interpreted very carefully. But as influences can be observed, this study could be completed by another one that could permit to distinguish emission and transport of particles, especially particles with a diameter less than 1µm that represent the major part of particle number concentrations.