In order to protect oneself and others from infection with SARS-CoV-2, the Robert Koch Institute (RKI) recommends wearing a mask covering both mouth and nose in certain situations in public places.
This applies in particular to situations where several people meet in closed rooms and stay there for a longer period of time (for example at the workplace) or if it is not possible for individuals to maintain a distance of at least 1.5 meters to others (for example in public transport or in shops).
It is important that the mask is worn tightly over the mouth and nose. Furthermore, it must be changed when it becomes wet; it must not be manually adjusted (even unconsciously) and must not be worn around the neck. A leaflet with information on the various types of masks can be found on the Internet at www.aachen.de/corona (in German, see Schutzmasken-ABC).