The effect of horizontal elements and building orientation on PM2.5 concentration in classrooms

Abstract

This study aimed to evaluate the effect of horizontal elements and building orientation on indoor particulate matter with a diameter of less than 2.5 μm (PM2.5) concentration and airflow. We added horizontal elements to the envelope of a standard Thai school building using computational fluid dynamics for testing the dispersion and concentration of PM2.5 in classrooms under the PM2.5 crisis condition in Chiang Mai Province. The results showed that the building orientation and the addition of horizontal elements to the front wall of the school building had different effects on the concentration of PM2.5 and airflow within the classroom in eight directions. Classrooms in standard school buildings facing NE and SW directions had the highest indoor PM2.5 concentrations, and those facing NW and SW had the least compared to all directions. Adding horizontal elements on the front wall of the standard school building was found to reduce the PM2.5 concentration in the classrooms of the building facing the N, NE, E, and SE directions. Increasing the horizontal element width from 1 m to 2 m reduced the PM2.5 concentration in classrooms of the N- and SE-facing buildings but had little effect in the classrooms of the NE- and E-facing buildings. This study will provide insight into the optimization of air quality in school buildings, informing the decision-making for adding horizontal elements and controlling their widths.