FFP2 masks, unlike FFP3 masks, “are not virus-proof masks,” explains virologist Norbert Nowotny of the University of Veterinary Medicine Vienna in an interview published by APA. This has to do with the smaller number of filter layers. Nevertheless, FFP2 masks would protect against viruses. The pore size of the filters is 600 nanometers, he said. SARS-CoV-2 viruses are only 100 to 120 nanometers in size, Nowotny explains, but they move in the air in the form of tiny droplets (aerosols) or adhere to dust particles. These are usually larger than 600 nanometers and are therefore also caught by FFP2 masks.
The filtering performance of the various FFP masks must be confirmed in special test procedures. For example, FFP2 masks must filter at least 94 percent of the test aerosols in tests to meet the European standard EN 149:2001+A1:2009, while FFP-3 masks must filter as much as 99 percent, the BfArM informs. The tests are not carried out with viruses, but with test aerosols. However, it is possible to draw conclusions about the infection protection effect of particle filters from this, according to a paper by the Münster University of Applied Sciences. The test standard is printed on the surface of the FFP mask, together with the CE mark and the four-digit identification number of the test institute. When buying one should pay attention to the correct labeling, according to the BfArM and the German Federal Institute for Occupational Safety and Health (BAuA).
Should FFP3 masks be used?
Now the question still arises whether one should not use the better FFP3 masks. The denser filter has the disadvantage, explains expert Nowotny, that it is difficult to breathe with it without an exhalation valve. However, masks without a valve would not only protect the mask wearer from viruses, but also the environment from viruses of the wearer. Therefore, he said, FFP2 masks without a valve are more suitable in the fight against the Corona pandemic.
In the health sector, FFP2 masks have been used for some time and are recommended by organizations such as the Robert Koch Institute (RKI) and the World Health Organization (WHO). In everyday use, the recommendations are not as clear.
The RKI, for example, points out on its website that no studies have yet been conducted outside the health care sector on the health effects of wearing FFP2 masks. When used by laypersons, it must be ensured, among other things, that “individual health suitability is assured and that a tight fit and correct handling are guaranteed.” The BAuA currently recommends the wearing of FFP2 masks outside the health care sector for “other activities” to increase self-protection or if the person opposite does not wear mouth-nose protection.
Virologist Nowotny is not yet aware of any study that would confirm an effect of widespread use of FFP2 masks in containing the Corona pandemic. But the previously described mode of action of the masks applies “generally to viral respiratory pathogens.”
Deutsches Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM) zu den verschiedenen Maskenarten: http://go.apa.at/x55CvPvM (archiviert: https://archive.is/DZWAf), FH Münster: http://go.apa.at/k9KNbkqV (archiviert: https://archive.is/M5aB8), Deutsche Bundesanstalt für Arbeitsschutz und Arbeitsmedizin (BAuA): http://go.apa.at/VmEbdUSd (archiviert: https://perma.cc/DPV2-N8HG), vienna.at/picture: hp
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