Characterisation of the off gases from a 500 A inert electrodeInert electrodes aluminium electrolysis cellAluminium electrolysis cells operating at a temperature of ca. 800 °C has been conducted using characterisation units comprising Gas Chromatography (GC), Tuneable Diode Laser Spectroscopy (TDLAS), and Fourier-Transform Infrared Spectroscopy (FTIR). The off-gases detected from the inert electrodeInert electrodes aluminium electrolysis cellAluminium electrolysis cells have been compared to the off-gases released from the traditional Hall–Héroult aluminium electrolysis cellAluminium electrolysis cells. All the measurementsMeasurements from the inert electrodeInert electrodes cell confirmed oxygen as the main process gas during the electrolysisElectrolysis process. HydrogenHydrogen fluorideFluoride/Particulate emissions, HF, which is assumed to result from reactions between moisture in the aluminaAlumina raw material or the surrounding air and the fluorideFluoride/Particulate emissions melt, was also observed together with gases assumed to come from air introduced, such as nitrogen and CO2CO2. There were no indications that these gases came from the production process. A very small amount of SIF4 was also detected.