Thus, the absence of combustion and smoke during EHTS use is by design. The scientific evidence available on EHTS use comprehensively demonstrates that no combustion process occurs when the EHTP is used in the EHTS Holder and that the aerosol generated is not smoke.
The definition of a combustion process and its specific characteristics are very well known in the fields of combustion science and fire safety and may be defined as an oxidative reaction of a fuel that occurs at a rate fast enough to produce heat and usually light in the form of either a glow or a flame [ , , , , , ].
Combustion is initiated by ignition and is self-sustaining as long as the exothermic (heat-generating) oxidation reaction is sufficiently strong to overcome heat losses and endothermic (heat consuming) processes, such as vaporization and endothermic thermal decomposition.
The burning of tobacco in a cigarette is an example of a self-sustaining smoldering combustion process, where temperatures in the range of 500–700 °C are generated at the burning tip of the cigarette when the tobacco is lit with a match or lighter [ , , , , , , ].