Double Mask Efficiency vs. Aerosols (Flow Simulation) 二重マスクの空気中粒子対策効率

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MASK AND ITS PERFORMANCE ANALYSIS WITH COMPUTATIONAL FLUID DYNAMIC (CFD) OF FILTERING SARS-COV-2 PARTICLES IN CONFINED SPACE

Nur Atiqah Surib, Muliani Mansor, Muhammad Syafiq Ridhwan Mohd Nasir, Jaalynee Kanniappan, I. Wuled Lenggoro, Khairunnisa Mohd Pa’ad (Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia Kuala Lumpur, Malaysia; Tokyo University of Agriculture and Technology)

Abstract

SARS-CoV-2 virus can be transmitted through the air to another person via travelling water droplets. The use of facial masks has been strongly recommended to prevent the transmission of this highly infectious disease. Latest recommendation suggested that double mask configuration of surgical and reusable masks perform comparably well to surgical and N95 masks. However, its efficiency has not been documented yet. In this paper, we investigated the effectiveness of double masks configuration to filter particles travelling through the air. We used particle tracing simulation study in the computational fluid dynamic (CFD) simulation. We simulated the movement of droplets sized between 1 𝜇m to 100 𝜇m. This took place as they moved through facial masks in a closed room when two people talked and sneezed. The total number of particles filtered, and filtration efficiency of each mask were calculated. Our findings indicate that the configuration of N95-reusable mask had the lowest amount of particle escape. It resulted in the best droplet filtering of all cases. For the movement of the droplets, 30 μm droplets that escaped from a surgical mask may reach 960 m. The 37 μm droplets that escaped from a N95 mask may reach 631 m. These results can improve future prediction efforts. We can better estimate the duration and efficacy of measures required. This is crucial to manage COVID-19 and other similar outbreaks.

Keywords: airborne transmission, double mask, SARS-CoV-2, filtration efficiency