What is it about?
COVID-19 spreads when a healthy person breathes in virus-laden droplets released into the air when an infected person sneezes or coughs. The two major entry points of these droplets in the body are the mouth and the nose. As such, doctors around the world advise covering the face with a mask. In addition, wearing a mask reduces the chances of someone breathing the infected droplets out. But, not all masks provide the same level of protection against viruses. Their filtration capacity depends on the arrangement of fibers in them. A mask with high filtration efficiency (FE) may provide better protection but make it hard to breathe. Choosing the right mask is therefore essential. Surgical masks (SM) are commonly used face protection. In this study, scientists have tried to understand how a three-layered SM fares in terms of protecting against the coronavirus. They used computer models to analyze changes in the airflow when inhaling through an SM and determined the viral load on it. They found that wearing a mask slows down airflow near the mouth and increases the area of inhalation. This may make it more likely to breathe in infected particles. However, wearing a mask does prevent deposition of particles in the lungs. A three-layered SM with 65% FE decreases the chance of deposition of 1-10 micrometer particles by three folds.
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Why is it important?
Scientists and doctors suggest masks are our first line of defense against the coronavirus. However, not all masks may be equally effective in protecting us from this deadly pathogen. This study shows that irrespective of their FE, all masks prevent the deposition of virus-laden particles in the lungs. Wearing a mask with an FE of at least 65% can protect us from viral deposition in the nose and lungs. KEY TAKEAWAY: Wearing the right mask decreases the chances of COVID-19 infection quite a lot. Masks with 65% FE are the best to keep the nose and lungs protected from the virus.
Read the Original
This page is a summary of: Effects of mask-wearing on the inhalability and deposition of airborne SARS-CoV-2 aerosols in human upper airway, Physics of Fluids, December 2020, American Institute of Physics,
DOI: 10.1063/5.0034580.
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Resources
Are cloth masks effective at reducing the spread of COVID-19 ?
To what extend face masks protect us against COVID-19 depends on material as well as design. Well fitted, thick layered cloth masks, and commercial cone-shaped masks are suitable at preventing the risk of airborne COVID-19 infection.
Why using a plain or surgical mask is always a better and safer choice
Studies show that wearing high quality cloth or surgical masks can protect against COVID-19. Face shields or valve masks may not be as effective at keeping infectious droplets out of the mouth or nose. This can increase the risk of infection.
Recharging N95 masks to make them reusable
This study suggests a simple method to extend the shelf life of N95 masks. The technique proposed can be used in other air filtration settings as well, including ventilation, air conditioning, and industrial filtration.
Air flow through N95 masks with and without exhalation valves
Current N95 masks with exhalation valves are not appropriate for use during a pandemic. They may not prevent infected air droplets from traveling outside the mask.
Making the most of our resources: Reuse and disinfection of N95 respirators
N95 respirators can be reused following dry heat sterilization at <100°C with no damage or loss of efficiency.
How do masks and ventilation affect the distribution of aerosols in indoor environments?
In an indoor setting with low ventilation rates, exhaled aerosols can be found even at a distance of two meters from their source. The use of highly efficient masks like N95 or K95 masks is recommended to prevent inhalation of these aerosols.
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