Abstract: The object of the invention is a composition for impregnating other materials, rendering them able to shield alternating electromagnetic fields in the range from low frequencies up to radio frequencies, containing an aqueous solution of salt that may form hydrates or a combination of salts, of which at least one forms a hydrate, characterised in that it contains an acrylic and/or styrene-acrylic dispersion and/or silicone emulsion and/or enhancing additives selected from a group containing surfactants and/or aluminosilicates and silicates and/or soluble and insoluble calcium compounds, metal and metalloid oxides, while an alternating field is shielded at least in range from 10?2 Hz to 106 Hz and its application for coating/impregnating fibrous and/or porous matrix and materials containing the thereof.