Fig. 3.

Mass fraction of tracer gas in the immediate upper room from the source at a lower floor in a slab-like building with various indoor/outdoor air temperature differences. For the results from Niu and Tung [26], SF₆ was released at a rate of 3 ml/s, and the mass fraction is the mass fraction of pollutant that originates from the upper opening of the lower room. For the results from Liu et al. [27], [28], CO₂ was released at a rate of 5 ml/s, and the mass fraction is the ratio of volume-average concentration in the upper room to that in the lower room.