Influence of indoor airflow on airborne disease transmission in a classroom

What is it about?

This paper aims to deepen the understanding of airborne disease spread in ventilated indoor environments. It examines the persistence and dispersion of pathogens of various sizes in a real classroom setting, under different ventilation scenarios, using a validated Computational Fluid Dynamics (CFD) method. Additionally, it introduces a novel airflow-related parameter called Horizontality to quantify and connect large-scale airflow patterns with indoor aerosol transport.

Featured Image

Photo by Andrew George on Unsplash

Photo by Andrew George on Unsplash

Why is it important?

It is widely accepted that increasing ventilation airflow, measured in air changes per hour (ACH), is the most effective way to mitigate airborne disease transmission in indoor spaces. However, merely increasing ACH has not proven effective in preventing the spread of COVID-19. A novel airflow-related parameter, Horizontality, is introduced to quantify and connect large-scale airflow patterns with indoor aerosol transport. This highlights that ACH alone cannot ensure or regulate air quality. In addition to the necessary ACH for air exchange, minimizing horizontal bulk motion is crucial for reducing aerosol transmissibility within a room. This paper introduces an enhanced ventilation design (UFAD-CDR) for university classrooms, which prioritizes mitigating airborne disease spread. Compared to the baseline design with the same ACH, this design successfully reduces the maximum number density of respiratory particles by up to 85%. This improvement can save many lives and also conserve significant amounts of energy during pandemics.