Human body heat shapes the pattern of indoor disease transmission

Abstract

Our study uncovered two thermal plume regimes-individual and collective-and a critical distancing threshold that triggers a transition between them, revealing novel disease spread patterns through the resulting morphological phase transition of airflow.Exhaled droplet and aerosol-mediated transmission of respiratory diseases, including SARS-CoV-2, is exacerbated in poorly ventilated environments where body heat-driven airflow prevails. Employing large-scale simulations, we reveal how the human body heat can potentially spread pathogenic species between occupants in a room. Morphological phase transition in airflow takes place as the distance between human heat sources is varied which shapes novel patterns of disease transmission: For sufficiently large distance, individual buoyant plume creates a natural barrier, forming a "thermal armour" that blocks suspension spread between occupants. However, for small distances,