COVID-19: Effects of environmental conditions on the propagation of respiratory droplets

Abstract

ABSTRACTAs Coronavirus disease 2019 (COVID-19) continues to spread, a detailed understanding on the transmission mechanisms is of paramount importance. The disease transmits mainly through respiratory droplets and aerosol. Although models for the evaporation and trajectory of respiratory droplets have been developed, how the environment impacts the transmission of COVID-19 is still unclear. In this study, we investigate the propagation of respiratory droplets and aerosol particles generated by speech under a wide range of temperature (0 °C to 40 °C) and relative humidity (0% to 92%) conditions. We show that droplets can travel three times farther in low temperature and high humidity environment, while the amount of aerosol increases in high temperature and low humidity environment. The results also underscore the importance of proper ventilation, as droplets and aerosol spread significantly farther in airstreams. This study contributes to the understanding of the environmental impact on COVID-19 transmission.