Human exposure to respiratory aerosols in a ventilated room: Effects of ventilation condition, emission mode, and social distancing

Airborne transmission of virus via respiratory aerosols plays an important role in the spread of infectious diseases in indoor environments. Ventilation and social distancing are two major control strategies to reduce the indoor airborne infection risk. However, there is a present lack of science-based information on how the human exposure to viral aerosols vary with ventilation condition and social distance. The objective of this study is to explore the transport patterns of respiratory aerosols in occupied spaces and assess the occupant exposure risk under different ventilation strategies, social distances and aerosol emission modes. The study results show that buoyancy-driven flow regime (can be found in many residential settings) can lead to a longer transmission distance and elevated exposure to viral aerosols than the mixing airflow, thereby causing higher cross-infection risk in indoor environments. The results also suggest that a 2 m (6 ft) social distance alone may not ensure control of indoor airborne infections.