Vaccinations, keeping your distance, thorough hand washing and disinfection, regular testing: there are a number of measures that we have been implementing since the beginning of the corona pandemic to contain the spread of the SARS-CoV-2 virus as much as possible. Among other things, wearing an FFP2 mask is also part of this: It offers extremely high protection against corona infection.
Because: respirators of protection class FFP2 filter at least 94 percent of the particles in the air up to a size of 0.6 micrometers (µm). Corona viruses themselves have a diameter of 0.12 to 0.16 ?m. As a rule, however, they are excreted as part of larger particles, which, depending on their size, stay in the air for different lengths of time and can be carried to different distances with the air flow.
An FFP2 mask protects against harmful water- and oil-based particles. It does not protect against carcinogenic substances, radioactive particles, airborne biological agents of risk group three or enzymes. At the beginning of the pandemic, the Robert Koch Institute recommended wearing either an FFP2 or an FFP3 mask, on the one hand to protect others from infection, but also so that the wearer does not become infected. Disposable, fabric or even medical masks protect the environment, but not oneself from infection with SARS-CoV-2.
In order for an FFP2 mask or KN95 mask (we have explained the difference between the respiratory masks here) to really guarantee this protection, it is important to wear it correctly, as researchers at the Max Planck Institute for Dynamics and Self-Organization in Göttingen are now investigating report a study. According to this, the probability of infection when wearing an FFP2 mask is 0.1 percent if an infected and a healthy person meet indoors at a short distance within a period of 20 minutes, according to an example scenario. Provided the mask fits properly, writes the team led by institute director Eberhard Bodenschatz in the “Proceedings” of the US National Academy of Sciences.
In the case of an incorrectly fitting FFP2 mask, however, the risk of infection in the same scenario is around four percent, as the team calculated. For optimal protection, the nose clip must therefore be shaped into a “rounded W”. This ensures that it presses on the sides of the nostrils and thus prevents particles from getting into the nose or mouth. With surgical masks, a good fit is enough to reduce the risk of infection to a maximum of ten percent.
The researchers calculated the risk of infection by combining many different factors such as particle sizes, exhalation physics, different mask types and risk of inhaling coronavirus and factored this into their results. “In everyday life, the actual probability of infection is certainly ten to a hundred times smaller,” Bodenschatz is quoted as saying in a statement from the institute, according to the DPA. If even the greatest theoretical risk is low, you are on the safe side under real conditions, the director of the institute explained.
The situation is completely different when two people meet who are not wearing a mask: the researchers explain that if a healthy person stands three meters apart in the air breathed by an infected person for a few minutes, there is a very high probability that he or she will become infected. Bodenschatz draws the conclusion: “Our results show once again that wearing a mask in schools and in general is a good idea” to protect yourself and others from infection.
If you buy an FFP2 mask, you should look for the so-called CE mark to make sure that they are legal in Europe. “The masks must regularly meet the requirements of the DIN EN 149:2009-08 standard,” says the website of the Federal Institute for Drugs and Medical Devices. In addition, an FFP2 mask should be disposed of after wearing and then changed, as it is usually intended for single use in order to be able to guarantee really reliable protection.
Sources used: Federal Environment Agency / Robert Koch Institute / DPA
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