In this study, the actual experiment done before was simulated using CFD and the detailed distribution of air velocity and CO2 gas concentration which is used as tracer gas of coughed air in a medical examination room were analyzed. Then advance conditions concerning evaporating droplet dispersion were calculated. The full scale chamber where the series of experiments have been conducted was modelled. The results of CFD proved that there was a deviation of CO2 concentration area in the chamber. Although it was observed many tiny droplets drift in the air, larger droplets were attached to both floor and human model.