Abstract
The motion of pollen grains invading through the window is simulated by the computational fluid dynamics and particle-tracking calculation. Here, the simulation software CAMPAS, which is developed in Gunma University, is employed. The objectives of the present study are to estimate quantitatively indoor dispersal of pollen grains in the case of massive ventilation and effectiveness of air purifier installation for pollen removal during weak ventilation. Pollen grains are set to be invading into the room through the window, and the room has the ventilation fan on the left side wall against the window. We calculate the ratios of the number of the pollen grains fallen on the floor, and vented out from the ventilation fan to the total invading pollens through the window. It is found that a substantial fraction of pollen grains fall on the floor near the wall opposite to the window and below the ventilation fan when the air change rate per hour is 8.3. We also study pollen removal efficiency of air purifier in the case that the air change rate per hour is 1.0. The number of removed pollen grains is found to be about half of the one of fallen pollen grains. We also found that pollen grains are widely distributed due to the turbulent air flow by air purifier.
