Boundary conditions for exhaled airflow from a cough with a surgical orN95mask

Abstract

Wearing surgical or N95 masks is effective in reducing the infection risks of airborne infectious diseases. However, in the literature there are no detailed boundary conditions for airflow from a cough when a surgical or N95 mask is worn. These boundary conditions are essential for accurate prediction of exhaled particle dispersion by computational fluid dynamics (CFD). This study first constructed a coughing manikin with an exhalation system to simulate a cough from a person. The smoke visualization method was used to measure the airflow profile from a cough. To validate the setup of the coughing manikin, the results were compared with measured data from subject tests reported in the literature. The validated coughing manikin was then used to measure the airflow boundary conditions for a cough when a surgical mask was worn and when an N95 mask was worn, respectively. Finally, this study applied the developed airflow boundary conditions to calculate person‐to‐person particle transport from a cough when masks are worn. The calculated exhaled particle patterns agreed well with the smoke pattern in the visualization experiments. Furthermore, the calculated results indicated that, when the index person wore a surgical and a N95 mask, the total exposure of the receptor was reduced by 93.0% and 98.8%, respectively.

Optimization of Cabin Virus Transmission Suppression Technology Based on Hanging Curtain Physical Isolation

“…Studies have shown that wearing masks could effectively reduce the number of droplets released into the air by the infection source and decrease the socialization distance to 0.5 m [12]. However, there are differences in filter efficiency and protective ability among the various types of masks on the market [13,14]. Researchers found that the survival rate of most bacterial particles in mask filtration layers (such as filter cores) can reach 44 to 77% [15].…”