#$%^&*AU2020100503A420200521.pdf#####Abstract So-called filter masks have been known for many years, which are intended to protect users (in private, industry, commerce and rescue workers, etc.) from dangerous substances (gases and particles of solid and liquid substances). Respiratory protection filters are divided into two main categories, namely particle filters and gas filters. In addition, so-called combination filters, which are supposed to offer protection against gases and particles, are available on the markets. The particle filters in turn are categorized into three different classes (P1, P2, P3), the service life of which depends on the load. Depending on the intended use, duration of wear, type of pollutant, etc., different mask types with various filter models are offered to filter hazardous substances from the breathing air, namely respiratory masks with one or more particle filters or particle-filtering half masks. Particle-filtering half masks are a mask and filter in one and therefore, no filter can be replaced after use. Moreover, particle-filtering half-masks mostly consist entirely of a filter material such as nonwoven fabric and are held on the user's head with elastic rubber bands and a ductile nose piece to enable optimal adaptation to the face. These filtering half masks are available with and without an exhalation valve - however, with the latter, the breathing resistance is considerably lower and the air humidity is drained through the valve, which increases comfort. This variant is widely used in the medical field to protect against infections. The respiratory masks have a corpus, that covers the mouth, chin and nose area and which is equipped with one or two exchangeable filter. The filter cartridges can be screwed on or fixed by bayonet catch. Full face masks additionally protect the user's eye area. Finally, the fan-assisted breathing protection should be mentioned, in which a head part and
