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Corona transmission: These materials keep most viruses out


Build mouth-nose protection: The best materials in the household

Everything indicates that there will be a temporary mask requirement in public once the measures are relaxed. If you don't have a ready-made mouth-nose protection ready, you have to use a self-made mask. The Max Planck Institute has now tested which household materials catch the most droplets.

Many materials found in every household are able to trap airborne particles and droplets that can contain infectious germs. The risk of infection with the SARS-CoV-2 coronavirus can be reduced, especially if all people in public places wear mouth and nose protection. The Max Planck Institute for Chemistry has now investigated which substances, cloths and materials in the household catch droplets particularly well. This material is suitable for building your own mouth and nose protection.

It doesn't have to be a purchased mask

What is already mandatory in supermarkets in Austria will soon also be implemented in Germany: wearing face-mask in public places. The National Academy of Sciences Leopoldina strongly advises that a relaxation of the measures should go hand in hand with a mouthguard requirement (see: return plan presented to normal). However, this does not have to be a purchased protective mask. Many household materials are ideal for building your own mask.

Which material is suitable for the construction of a mouth-nose protection?

Researchers at the Max Planck Institute for Chemistry tested how well various household substances are suitable for building your own mouth-nose protective mask. Many common materials performed surprisingly well. Cotton fabrics such as jersey, beaver and fleece from vacuum cleaner bags were particularly convincing.

Filter material is particularly suitable

The investigation showed that many different materials are suitable for the construction of a protective mask. Such material should be in every household. "We found that all of the filter materials investigated, particularly large particles of five microns and larger, separate very efficiently," explains Frank Drewnick, head of research in the particle chemistry department. Filter material such as coffee filters and vacuum cleaner filters were able to trap over 90 percent of the larger particles that seem to play a particularly large part in the spread of infection.

Small droplets are harder to catch

With particles that are smaller than 2.5 microns, most materials reach their limit. But there are also clear differences in this area. For example, microfiber cloths held less small particles than vacuum cleaner fleece or a combination of cotton and beaver. Even though corona viruses are only around 100 nanometers in size, current knowledge indicates that they are mostly transported with larger droplets.

The material must allow enough air to pass through

According to the Max Planck Institute, materials are particularly well suited for air to flow through, but at the same time capture many particles. This ensures that the face mask can also breathe well. A combination of jersey and beaver fabric performed particularly well in terms of air permeability combined with a high filter effect. But also double-layered solid cotton fabric and a combination of vacuum cleaner bag material and cotton fabric were convincing. Coffee filters hold up a lot of particles, but are hardly air-permeable and therefore not particularly practical, write the researchers.

It's not just the material that counts

“Our data make no statement about how well a face mask actually protects. However, they may help you select suitable filter materials for self-sewn, ”emphasizes Drewnick. The effectiveness of a mask is dependent on many factors, such as correct handling, how much air flows past the mask, how often and how the mask is cleaned. In addition, factors such as skin tolerance and comfort could also play a role, but this was not taken into account in the investigation. (vb)

Author and source information

This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.

Graduate editor (FH) Volker Blasek

Swell:

  • Dr. Frank Drewnick, inter alia: separation efficiency of mouth-nose protection masks, self-sewn face masks and potential mask materials; Max Planck Institute for Chemistry (published: April 10th, 2020), mpic.de
  • Max Planck Institute for Chemistry: Fabrics, paper towels or vacuum cleaner bags against Corona (published: April 10th, 2020), mpic.de


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