Kai Lordly, Leya Kober, Mehdi Jadidi, Sylvie Antoun, Seth B Dworkin, Ahmet E Karataş
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Understanding lifetime and dispersion of cough-emitted droplets in air.
To understand the exact transmission routes of SARS-CoV-2 and to explore effects of time, space and indoor environment on the dynamics of droplets and aerosols, rigorous testing and observation must be conducted. In the current work, the spatial and temporal dispersions of aerosol droplets from a simulated cough were comprehensively examined over a long duration (70 min). An artificial cough generator was constructed to generate reliably repeatable respiratory ejecta. The measurements were performed at different locations in front (along the axial direction and off-axis) and behind the source in a sealed experimental enclosure. Aerosols of 0.3-10 µm (around 20% of the maximum nuclei count) were shown to persist for a very long time in a still environment, and this has a substantial implication for airborne disease transmission. The experiments demonstrated that a ventilation system could reduce the total aerosol volume and the droplet lifetime significantly. To explain the experimental observations in more detail and to understand the droplet in-air behaviour at various ambient temperatures and relative humidity, numerical simulations were performed using the Eulerian-Lagrangian approach. The simulations show that many of the small droplets remain suspended in the air over time instead of falling to the ground.
期刊介绍:
Indoor and Built Environment publishes reports on any topic pertaining to the quality of the indoor and built environment, and how these might effect the health, performance, efficiency and comfort of persons living or working there. Topics range from urban infrastructure, design of buildings, and materials used to laboratory studies including building airflow simulations and health effects. This journal is a member of the Committee on Publication Ethics (COPE).