With the Inert Gas Module (IGM) we give the user the possibility to study the impact of the absence of oxygen of the collected total particulate matter as well as the impact on the gas phase constituents e.g. nitrogen oxides and carbon monoxide when puffing heated tobacco products. The chamber can be flushed continuously with an inert gas e.g. nitrogen to supersede any oxygen and therewith to avoid any combustion effect. Having this opportunity a direct comparison of the constituents and their concentrations between regularly puffed and IGM puffed heated tobacco products will give a strong indication that the tested product did not undergo a combustion or pyrolysis process and demonstrates that the aerosol generated is formed principally by vaporization of an aerosol former, water and some tobacco constituents.