An assembled air filter for removing solid particles and/or gases, including biological and chemical warfare agents and radioactive substances, from ambient air, said assembled air filter being composed of a plurality of air filters stacked one on top of the other and comprising - a hollow cylindrical housing having an inner cylindrical shell and an outer cylindrical shell, each of which are gas-permeable cylindrical shells, one of which serves as an air inlet and the other of which serves as an air outlet, - cylindrical partition walls (17, 18) which divide the space between the inner and outer cylinder jackets (11, 12) into substantially concentric, hollow cylindrical chambers (21, 22), wherein a chamber oriented closer to the air inlet comprises a particle filter and a further chamber oriented closer to the air outlet contains a material for absorbing gaseous substances, such as in particular activated carbon, wherein both end faces of the hollow cylinder are each closed by a continuous, annular end plate (30, 30'), wherein the end plates (30, 30') are each connected in a fixed and gas-tight manner to the inner and outer cylinder shells (11, 12) and to the cylindrical partition walls (17, 18) characterised in that - the end plates (30, 30') have, on their outer side facing away from the filter material, at least one annular circumferential beading which, for receiving sealing rings, are designed as annular depressions concentric with the axis of the hollow cylinder, - the headings are arranged on opposite end plates (30, 30') on the same radius with respect to the axis of the hollow cylindrical housing, - the end plates (30, 30'), apart from the headings, form flat surfaces, - the headings on each of the end plates (30, 30') lie in a common plane, and - in the headings of immediately adjacent end plates (30, 30') lie sealing rings whose cross-sectional diameter measured perpendicular to the plate plane is more than twice the depth of a beading, so that the seals received in both headings of opposing end plates keep the end plates parallel and spaced apart from each other. - a hollow cylindrical housing having an inner cylindrical shell and an outer cylindrical shell, each of which are gas-permeable cylindrical shells, one of which serves as an air inlet and the other of which serves as an air outlet, - cylindrical partition walls (17, 18) which divide the space between the inner and outer cylinder jackets (11, 12) into substantially concentric, hollow cylindrical chambers (21, 22), wherein a chamber oriented closer to the air inlet comprises a particle filter and a further chamber oriented closer to the air outlet contains a material for absorbing gaseous substances, such as in particular activated carbon, wherein both end faces of the hollow cylinder are each closed by a continuous, annular end plate (30, 30'), wherein the end plates (30, 30') are each connected in a fixed and gas-tight manner to the inner and outer cylinder shells (11, 12) and to the cylindrical partition walls (17, 18) characterised in that - the end plates (30, 30') have, on their outer side facing away from the filter material, at least one annular circumferential beading which, for receiving sealing rings, are designed as annular depressions concentric with the axis of the hollow cylinder, - the headings are arranged on opposite end plates (30, 30') on the same radius with respect to the axis of the hollow cylindrical housing, - the end plates (30, 30'), apart from the headings, form flat surfaces, - the headings on each of the end plates (30, 30') lie in a common plane, and - in the headings of immediately adjacent end plates (30, 30') lie sealing rings whose cross-sectional diameter measured perpendicular to the plate plane is more than twice the depth of a beading, so that the seals received in both headings of opposing end plates keep the end plates parallel and spaced apart from each other. - the end plates (30, 30') have, on their outer side facing away from the filter material, at least one annular circumferential beading which, for receiving sealing rings, are designed as annular depressions concentric with the axis of the hollow cylinder, - the headings are arranged on opposite end plates (30, 30') on the same radius with respect to the axis of the hollow cylindrical housing, - the end plates (30, 30'), apart from the headings, form flat surfaces, - the headings on each of the end plates (30, 30') lie in a common plane, and - in the headings of immediately adjacent end plates (30, 30') lie sealing rings whose cross-sectional diameter measured perpendicular to the plate plane is more than twice the depth of a beading, so that the seals received in both headings of opposing end plates keep the end plates parallel and spaced apart from each other.