Abstract: A mobile purification device for purifying indoor air and/or fresh air, has a holder and a filter element having a particle-filtering and a gas-adsorbing region, the particle-filtering region having a filter medium and the filter element being received in the holder to purify indoor air and/or fresh air containing smoke and/or particles and is useful as a mobile purification device, filtering particle-polluted and/or smoke-polluted indoor air and/or fresh air as effectively as possible, with particulate, emitted contaminants being prevented as far as possible from being discharged from the gas-adsorbing region into a space, wherein the particle-filtering region faces a downstream side of the holder and in that the gas-adsorbing region faces an upstream side, which can be supplied with indoor air and/or fresh air polluted with smoke and/or particles.

Abstract: A layer for use in a HEPA filter element solves the problem of disclosing a filter element which satisfies HEPA requirements. Said layer comprises a first support layer (1) for stabilization which contains polypropylene fibers, and a second deposition layer (2) which contains polypropylene fibers, wherein the polypropylene fibers of the deposition layer (2) are at least partially electrostatically charged, and wherein the support layer (1) and the deposition layer (2) are constructed as nonwoven material which is at least partially free of glass fiber. The layer according to the invention can be easily pleated while having excellent filter efficiency.

Abstract: A printer (1) with a toner-based printing device, the printer (1) comprising at least one air outlet (2), to which a filter (3) is fastened exchangeably, for the outflow of the gas contained in the printer (1) into the surroundings, the filter (3) comprising at least one electrostatically active filter ply (4).

Abstract: A layer for use in a HEPA filter element solves the problem of disclosing a filter element which satisfies HEPA requirements. Said layer comprises a first support layer (1) for stabilization which contains polypropylene fibers, and a second deposition layer (2) which contains polypropylene fibers, wherein the polypropylene fibers of the deposition layer (2) are at least partially electrostatically charged, and wherein the support layer (1) and the deposition layer (2) are constructed as nonwoven material which is at least partially free of glass fiber. The layer according to the invention can be easily pleated while having excellent filter efficiency.