Facemasks in the time of coronavirus are important for healthcare workers, to protect professionals from being hit with splashes of body fluids, and to protect patients should a healthcare worker develop COVID-19 symptoms. Whether the general pubic should wear facemasks is a matter of debate; certainly facemasks supply should not be taken from the health economy. The reason why there is a debate is because the facemask reduces the risk of transmission if someone has the SARS-CoV-2 virus, but they are not very effective in terms of preventing someone from contracting coronavirus. Other measures are more important, such as social distancing and effective hand disinfection.
The following video expand on this debate:
Where people feel the need to use facemask, and have no choice but to fashion their own, which materials are best? Scientists have undertaken experiments and they have concluded that a combination of cotton with natural silk or chiffon is the best option for filtering out the majority aerosol particles . However, it is very important that the fit is good. If the mask does not fit properly, there remains a greater chance of releasing viral particles on the part of the mask wearer. With the gap, just a 1 percent gap reduced the filtering efficiency of a mask made from any material by at least 50 percent.
For the assessment, the scientists deployed an aerosol mixing chamber to generate particles ranging from 10 nm to 6 μm in diameter. The aerosol was directed, using fans, at various cloth samples. The airflow rate was established as a person’s respiration at rest. From this, the researchers measured the number and size of particles in air before and after passing through the fabric.
This study revealed that polyester-spandex chiffon filtered out the most aerosol particles (80-99 percent, depending on particle size). The use of natural silk produced similar results. This was because these materials hold a static charge, which acts as an electrostatic barrier.
The findings are reported to the journal ACS Nano, in a paper titled “Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks.”
