Ventilation methods to prevent the spread of airborne pathogens from teachers to students

Abstract

This study investigates different ventilation systems to prevent the spread of airborne pathogens from teachers in an elementary school classroom setting. The analyzed systems include a general mechanical ventilation system and a hybrid ventilation system. The hybrid ventilation system used a combination of natural ventilation, general mechanical ventilation, and local mechanical ventilation systems. For natural ventilation, wind velocities of 1.1 m/s and 0.11 m/s were considered. To analyze the patterns of the spread of airborne pathogens, the indoor airflow patterns and concentrations of airborne pathogens (passive scalar) were examined using Star-CCM + . Comparing the methods confirmed that natural ventilation was more effective than general mechanical ventilation in removing the airborne pathogens discharged from the teacher. The proposed hybrid ventilation method with combined natural and mechanical ventilation also showed promise in removing airborne pathogens. However, for natural ventilation with low wind velocity, the buoyancy effect around the occupants creates airflow vortices in the front of the classroom which spread airborne pathogens from the teacher toward the students seated in the front of the classroom. Furthermore, operating a local ventilation system close to the teacher reduced the spread of airborne pathogens that occurred under natural ventilation conditions with low wind velocity.