Transparent masks: chic but ineffective
Christiane Fux studied journalism and psychology in Hamburg. The experienced medical editor has been writing magazine articles, news and factual texts on all conceivable health topics since 2001. In addition to her work for, Christiane Fux is also active in prose. Her first crime novel was published in 2012, and she also writes, designs and publishes her own crime plays.
More posts by Christiane Fux All content is checked by medical journalists.Transparent masks are more comfortable for the wearer. And they enable the other person to recognize facial expressions. But as nice as a smile may be, especially in corona times - they do not offer other people protection from infection. In fact, such masks could even encourage the spread of the virus.
This is what a team of researchers from Munich University of Applied Sciences discovered in a pilot study. "With our experimental set-up, we can precisely measure how the spread of aerosols is influenced by masks of this type," explains study leader Christian Schwarzbauer, professor of medical technology and medical informatics.
Swirling aerosol clouds
The problem with the models: On the lower side, a gap of one to several centimeters remains free between the face and the mask, through which aerosols can flow out unhindered.
In the first experiment, the subject sat on a chair and breathed through their nose. First, as advertised by the manufacturer, the aerosol flows down the body. Shortly thereafter, however, it is deflected at the top and spreads in the area in front of the mask wearer. A person sitting opposite would be fogged in a short time.
After a few seconds, the aerosol was already floating over the subject's head. The exhaled air is warmer than the room air and therefore rises.
If the person wearing the clear mask walks around the room and coughs, the effect is even more fatal. An extensive aerosol cloud forms, which quickly expands further in space. Seated people would then lavishly swirl around the cloud, especially in the area of the face and upper body.
"No effective protection"
The results of this pilot study illustrate the problems with this mask design. “Without a doubt, these masks are comfortable to wear. However, they do not offer effective protection against infections, ”says Schwarzbauer. The researchers urgently advise against the use of such masks, especially in closed rooms such as schools, daycare centers, offices, restaurants or public transport.
Bavaria - possibly based on the study - classified the transparent masks as unsafe. This is reported by the Süddeutsche Zeitung, among others. Plastic shields, which also allow aerosols to escape downwards and also on the sides, had already been declared unsuitable by experts in the summer for similar reasons.
