Improving indoor air quality in primary school buildings through optimized apertures and classroom furniture layouts

Abstract

This study aimed to examine the influences of the opened to total aperture area (the O/A ratio) and furniture arrangements in a naturally ventilated classroom's internal ventilation and PM 2.5 deposition. For the experiments, four cases were established for the O/A ratio and layout. Computational fluid dynamics (CFDs) was validated and applied, using the ANSYS Fluent software, to determine the velocity and concentration of PM 2.5 in the primary school classroom. The results indicated that different furniture arrangements and O/A ratios affected the air velocities and PM 2.5 concentrations, and could improve indoor air quality. The furniture arrangement affected the PM 2.5 concentration at a height of 0–1.6 m, and concentrations at the inlet and outlet, as well as near the classroom wall, which were higher than that in the center. The U-shaped layout reduced the concentrations of PM 2.5 and the natural air in the classroom, yielding a minimum vertex in the middle of the classroom, particularly in the breathing zone of elementary students. Moreover, the indoor PM 2.5 concentration increased, with an increasing ratio of apertures in the classroom. An O/A ratio of 1 corresponded to the highest air velocity and PM 2.5 concentration in the classroom, with high turbulence in the middle. A ratio of 0.25 corresponded to the least PM 2.5 concentration in the classroom, particularly at below 2 m. Thus, applying the optimized results, an O/A ratio of 0.25 and the U-shaped furniture layout, to a classroom significantly lowered its PM 2.5 concentrations.