Simulation of COVID-19 indoor emissions from coughing and breathing with air conditioning and mask protection effects

Abstract

The COVID-19 infection has emerged as a disruptive pandemic at worldwide level. The study of the mechanism of contagion is one of the greatest challenges before a mass vaccination campaign that would protect populations. The study can support the development of knowledge and tools to develop possible strategies for containing its spread in future events. The saliva droplet aerosol expelled during breathing or coughing is the main cause for the propagation of the SARS-Cov-2. In this work, a URANS CFD approach was used to simulate the dispersion from the mouth of these particles in closed environments. The air conditioning system was considered. The conditions were varied to determine their impact on the diffusion of the aerosol. Lagrangian and Eulerian numerical approaches were used to model the coughing and the breathing events. These were validated with the puff theory, numerical and experimental results. A realistic case of a meeting room with two persons was simulated. Different characteristics of the expulsed aerosols and different ventilation system configurations were considered to demonstrate how these simulations can support management strategies for indoor occupation. Finally, the effect of the protective mask was introduced to quantify its beneficial effects to support safe indoor occupation.

Multiple airflow patterns in human microenvironment and the influence on short-distance airborne cross-infection – A review

“…6,36,38 The rapid spreading of COVID-19 highlights the importance of better understanding of the dynamics and transmission routes of the expelled virus-laden droplets from these respiratory activities. 39,40 Inhalation Droplets or aerosols containing infectious pathogens inhaled by a susceptible person may cause infection. Inhalation route is considered as one important pathway of SARS-CoV-2 transmission as reported in the issued scientific brief by WHO on 30 April 2021.…”

“…6,36,38 The rapid spreading of COVID-19 highlights the importance of better understanding of the dynamics and transmission routes of the expelled virus-laden droplets from these respiratory activities. 39,40…”

Using global research on ventilation and airborne infection control for impacting public policy through the Indian Judiciary

“…Research in the area of the spread of airborne diseases in enclosed environments has been done by researchers across the world. 8 It is essential for good research to become part of public policy as soon as possible. This is all the more essential in the COVID-19 pandemic when every step taken in the right direction for prevention of disease spread can save countless lives.…”

Computational characterization of the behavior of a saliva droplet in a social environment

“…This phenomenon depends on many factors; the speed at which it is generated, whether we are in a closed or open place, anyhow there is a high-speed wind or a soft breeze, regardless there is ventilation, etc. In fact, the study by Cravero et al 17 , indicates that with adequate ventilation in an indoor environment completely changes the direction of exhaled flow. Stiti 15 has found that a particular 80 µm becomes solid waste before reaching the ground when the person exhaling it has a height of 1.6 m from the mouth to the ground.…”