Abstract: The invention relates to a method for operating a ventilation system for indoor air in an indoor space, in particular a motor vehicle. The method comprises the steps of: providing a fresh air portion of supplied fresh air and a recirculated air volume flow according to a predetermined or selected operating strategy; determining settings for a recirculated air actuator for adjusting a fresh air portion, in particular a recirculated air flap or a recirculated air valve, and a fan power of a fan for adjusting a mixed air volume flow (QM) of supplied recirculated and fresh air; increasing the fresh air portion and/or the mixed air volume flow (QM) as a function of a pathogen filtration efficiency of a cabin filter and a predetermined contamination prevention volume flow as a pathogenic indoor concentration limit value (CP) for a maximum concentration of pathogenic aerosols.

Abstract: The invention relates to a method for operating a ventilation system for indoor air in an indoor space, in particular a motor vehicle. The method comprises the steps of: providing a fresh air portion of supplied fresh air and a recirculated air volume flow according to a predetermined or selected operating strategy; determining settings for a recirculated air actuator for adjusting a fresh air portion, in particular a recirculated air flap or a recirculated air valve, and a fan power of a fan for adjusting a mixed air volume flow (QM) of supplied recirculated and fresh air; increasing the fresh air portion and/or the mixed air volume flow (QM) as a function of a pathogen filtration efficiency of a cabin filter and a predetermined contamination prevention volume flow as a pathogenic indoor concentration limit value (CP) for a maximum concentration of pathogenic aerosols.

Abstract: A method includes: using a planar substrate having at least one acid-functionalized layer including at least one first acid having a pks1 value of 0 to 7 and at least one different second acid or derivative thereof selected from a group consisting of C8 to C18 fatty acids, esters, amides, and mixtures thereof, as a filter medium for depleting viruses from air and other gases.

Abstract: A filter medium includes: a functional layer; and two nonwoven layers. The functional layer is arranged between the nonwoven layers. The functional layer includes antiallergenic substances. The antiallergenic substances comprise a pourable or free-flowing solid. In an embodiment, the solid comprises a granulate. In an embodiment, the antiallergenic substances include polyphenols or fruit acids.