A good fit of the mask is essential. However, the problem is that, in the vast majority of cases, citizens are satisfied that it does not fall out of their face. But nothing is further from reality: as Professor Jose Luis Jimenez, a chemist at the University of Colorado, in the United States, explains, the virus is capable of taking advantage of the tiniest holes.
“To filter aerosols, we need quality in the filter and the fit of the mask on the face. Because if there are gaps between the face and mask, it is easier for the air to escape through them. A gap of 2% of the mask area leaves past 50% of the air unfiltered, “he warns on his Twitter account.
In this sense, Jimenez has compiled a multitude of studies that talk about the three types of transmission of the disease (inhalation of aerosols, spray drops, and touching contaminated surfaces). And it also specifies how the masks are related to this type of contagion. For example, in the second case (when we speak we ‘shoot’ saliva with the virus) a well-fitted mask or of high quality is not necessary. Even so, the problem is in the other ways: there it is essential to know how to put on the protection. In this sense, the expert highlights the video from the Delft University of Technology (Netherlands), which shows what happens to exhaled air when the reusable surgical or hygienic mask does not fit the face well.
As can be seen in the images, much of the unfiltered air escapes through the sides. “Half of the unfiltered air passes through holes that seem small to us,” insists Jimenez, who highlights how these “leaks” are observed in the video. In this sense, a study from Singapore highlighted that only 13% of people can put on the N95 masks correctly (very similar to the FFP2): “It is difficult to get a good fit, especially on the nose. You have to work a lot and adjust the nose iron very well so that it seals “, says the expert.
How to fit the mask well.
Harvard Councils Professor Joseph G. Allen, director of the Healthy Buildings program at the T.H. Chan from Harvard also cautions that mask fit is critical. And, in this sense, it gives some advice to prevent what Jiménez denounced from happening. In this way, the specialist recommends that every time we put on a mask, we verify that it is sealed. How? “Put your hands on the mask to block the air and exhale gently. You should not feel air coming out of the side or up towards your eyes,” he explains. Next, he advises moving your head from side to side and in a circle to make sure that the mask does not move out of place. Finally, Allen recommends one last trick to make sure of the placement of the object: read a passage of text to verify that the mask does not slip too much when speaking. If you do not notice the air around, it would be well placed