Textile face masks against coronavirus
On 11 March, the WHO declared the coronavirus a world-wide pandemic. All over the world people are asking: how can I protect myself? Textile researcher and biologist Dr. Anja Gerhardts explains how commercially available face masks work – and how they don’t.
Dr. Gerhardts, does the coronavirus have an impact on your current working day?
Yes, absolutely. The question of face masks, for instance, is currently of great concern to us.
In what way?
Every day we receive enquiries from industry, asking us to test new materials to ascertain their protective effect and their suitability as face masks. Because many of these materials have up to now not been used for such an application, never mind for virus protection, it is necessary to investigate thoroughly whether they are suitable for this purpose at all. And anti-viral appurtenances, for cleaning cloths for instance, are now coming into increased research focus again.
As a private individual, can I use a face mask to protect myself against an infection?
A simple face mask, which usually consists of non-woven material, provides no sufficient protection. It is much too porous; moreover viruses can always be caught via the mucous membranes of the eyes. Viruses are absolutely tiny, their size is measured in nanometres, so the material must have a high density if it is to protect efficiently. Unfortunately that is not the case with a face mask which is more in the nature of a splash guard.
So can we leave off the face mask entirely?
Not necessarily. It certainly does provide protection, but in a way different from the one people imagine: if it is worn correctly by an infected person, i.e. closely over the nose and mouth, and not for too long so it gets soaked, it does catch infectious aerosols which are released by sneezing and coughing. So infected people who need to move in public areas can protect others from an infection by means of a face mask, and thus prevent the spread of germs.
What about respirator masks?
Their protective effect is substantially greater, since they consist of several layers of non-woven materials of an absorbent and electrostatic type. In this way viruses and particles are blocked very much better from the air than with a simple face mask. There are respirator masks giving various levels of protection, depending on how well dust, germs and fluid and solid particles are blocked.
Textiles are in daily use in hospitals and care homes, for instance as surgical gowns, dressings, bandages or orthoses. Can fibres help to prevent the spread of viruses?
To reduce and shorten the spread and survival of germs and viruses in the environment, surgical gowns for instance have a barrier function. And textiles near to patients are coated with active anti-microbial agents. The aim is to interrupt chains of infection and to reduce the probability of any transmission.
Dr. Gerhardts, many thanks for the interview.
Since 2017 Dr. Anja Gerhardts has been the head of research and development at Hohenstein, a research and service centre near Stuttgart. Here textile researchers, biologists and chemists, among other projects, are developing methods of investigating the efficacy of anti-microbial textiles, scrutinising the performance of washing procedures, and investigating the transmission channels of germs, in order to break chains of infection better.