IQAir GC MultiGas Cartridges Filter SetQuick Overview This is the filter cartridge set for GC Multigas air purifier. The GC Multigas cartridge has approx 5. 4 Kg granular activated carbon and impregnated alumina (AC 4+IA 4) For a broad spectrum of gaseous pollutants and odours, including: Hydrocarbons VOC Sulfuric oxides Formaldehyde Hydrogen sulphide Lower molecular aldehydes Organic acids Nitrogen oxides, Higher molecular gases Odours and ozone