Masks are currently on everyone’s lips. It would be better if everyone were talking about them, but that can happen. So it’s time to browse the range a little and look at the quality. Not all masks protect, that much is clear. But which ones form a particularly good barrier against the coronavirus and prevent it from spreading?
A new US study now comes to a surprising conclusion. Various multi-layer fabric masks, consisting of a dense cotton and at least one additional layer of silk, flannel or chiffon, are just as good at catching droplets as medical masks of the type N95.
The latter is a close-fitting, anatomically shaped mouthguard for medical professions that hugs the mouth, nose and upper chin and has good filter properties. They are not to be confused with the FFP masks that doctors and nurses use to treat infected people in hospitals.
The latter are the only ones that offer 100 percent protection against the virus, even when it is suspended in the air in tiny aerosols. This happens, for example, when a patient is connected to the ventilator and droplets with the virus are virtually pulverized.
N95 masks filter 99.9 percent of all droplets over 300 nanometers
A group of American researchers tested fabric masks made of various materials in a test arrangement in which the protective masks were bombarded with droplets of different sizes. The scientists documented how well the protective accessories caught droplets that were larger or smaller than 300 nanometers.
Cotton fabrics of different densities, different densely woven silk fabrics, chiffon and flannel were among the test objects. Fabric lovers know that the density of the weave in cotton or silk plays an important role in the quality. The more densely a cotton or silk is woven, the higher quality it is and the less foreign matter it lets through.
The study revealed: N95 masks filter 99.9 percent of all droplets that are larger than 300 nanometers, provided they fit closely to the face. With droplets that are smaller than 300 nanometers, they still filter an average of 85 percent. If there is a gap between the face and the mask because it was put on incorrectly, the filter performance drops significantly. The tiny particles under 300 nanometers are only kept 34 percent off.
Cotton plus silk, flannel or chiffon filter just as well
The multilayered masks made of dense cotton plus silk, flannel or chiffon filter between 94 and 97 percent of the small virus spinners below 300 nanometers. With the larger droplets, they held off between 96 and 99.2 percent and thus performed as well as the N95 mask.
Another essential finding of the researchers was that the best mouthguard is hardly effective if there is a gap between the mask and face. It’s a bit like snorkeling: the most expensive diving goggles are of no use if they are too big, wobble back and forth in the face and lick. The research group therefore points out that in the future it will be important to provide anatomically well-fitting masks and to communicate how important it is to keep the face close.
Whether we are having fun or not having fun with the masquerade. If the majority of all citizens wear a medical mask of the type N95 or one of the multilayered fabric masks described above, wash their hands regularly and keep their distance from the person opposite, the virus can no longer multiply via droplets from a certain point in time. Then in the foreseeable future there can be football again, barbecues and finally normality again.