MONDIAL: Mouth and nose masks: alternatives to the surgical mouth and nose mask

Background There is a global shortage of medical-grade face masks. At the same time, face masks can play an important role in limiting the spread of SARS-CoV-2. This project investigates whether there is an effective mask for the public to wear in public that can be made from readily available materials. Results The best alternative to a medical face mask is a mask made from a ventilation system filter. This mouth and nose mask is more effective than masks labelled as "surgical masks", if properly made. With filter class ePM1 85%, which indicates how many fine dust particles it filters, you approach the capacity of an FFP2 mask used in healthcare. In the tests, a mask with the shape of a duckbill worked best because it seals better. A mask made of two layers of cotton fabric with kitchen paper in between as a filter is a reasonable alternative made from more available materials. The filter test was done in a so-called particle chamber where particles as large as a virus particle are sucked in. The number of particles sucked through the fabric was measured. In addition, it was examined which materials and models fit the skin best, whether the materials breathe sufficiently and whether they could be washed.