becomes somewhat similar to that of the inhalation region as is shown in Fig. 15(1). The standing occupant inhales the contaminated air drawn up from the lower part of the body. The air behind the occupant has little e&ect. (ii) Sleeping. When sleeping, the region of SVE5 with a higher value coincides almost exactly with the region of higher concentration of contaminants emitted from the 8oor.
ccordingly, the distribution of IECI is higher in the area adjacenttotheheadoftheoccupant,andisnearto0throughout the rest of the area as is shown in Fig. 15(2).
3.2.5. Residual lifetime of air to be inhaled Residual lifetime of the air to be inhaled at each point is calculated by the average time taken by a tracer to move
from the point to the mouth when the tracer is emitted in a pulse at this point.
(i) Standing. When an occupant is standing, inhalation residual lifetime is shorter in the area from the mouth to the lower area as is shown in Fig. 16(1). It is clear that the freshairfromthesupplyopeningenterstheregionofinhalation, drawn upward by the thermal resulting from metabolic
heating. The air in the region extending from the head to the exhaust opening hardly reaches the region of inhalation at all, but moves away towards the exhaust opening. Interestingly, the distribution of residual lifetime for air to be inhaled corresponds inversely to that of IECI. In the region of higher IECI, the residual lifetime for air to be inhaled is shorter (Fig. 15(1)). (ii) Sleeping. The residual lifetime for air to be inhaled is relatively low when sleeping on the 8oor compared to that when standing, as is shown in Fig. 16(2). The air near the chest is transported to the upper part of the room by the rising air stream due to metabolic heating.