From today 11 July 2020, wearing a mouth mask is mandatory in Belgium. But how well do these mouth masks actually work? How useful are they?
Last week, De Standaard published the test results of a number of types of mouth masks. In particular, to what extent a mask protects against the total number of fine particles in the air, was tested with a device that can very quickly show which masks meet the standard European filter norms.
The Belgian company Envicontrol - which in fact is not an accredited lab, but rather a distributor and supplier of test equipment to, among others, the Flemish Environment Agency - carried out the tests. The Standaard focused on the "normal" masks and therefore not on the specialised FFP masks, which are reserved for the medical sector.
The most important conclusions
1. All mouth masks tested, from the surgical mouth mask over the homemade mouth mask to even a well woven scarf, stop most particles above 5 microns. This means that the droplets needed by the corona virus to survive and move around are well retained and do not leave the mask. By wearing a mouth mask yourself you do protect the people around you.
2. Homemade mouth masks or scarves barely protect yourself, but we do protect the others. Homemade and unfortunately also surgical mouth masks still let air through at the sides. In other words: all these masks mainly prevent you from infecting the other person, but don't really take away the risk of becoming infected yourself.
Only the hospital mouth mask and the well-known better blue surgical mouth mask reach the filtration level of a professional FFP1 mask. In addition, the masks for the medical sector are also biologically tested for the survival of viruses.
3. Indoors, the number of airborne particles is very high. So especially in enclosed indoor spaces such as living rooms and meeting rooms, there are a lot of particles that you can only limit with very good ventilation. Keeping a distance is the most important rule, both indoors and outdoors.
4. The government's free mouth mask, which was the subject of so much discussion, is not really a textbook example of a good purchase. A homemade mask with the government filter scores 42% in the standard test. That is in the yellow zone: acceptable, but not really good.