Why combustion is the primary problem with cigarettes

Burning tobacco creates high levels of harmful chemicals

Decades of scientific research show that the primary cause of smoking-related diseases is the high levels of Harmful and Potentially Harmful Constituents (HPHCs) in smoke formed during the burning process. When a cigarette is lit, the tobacco inside it combusts (burns), producing ash, heat, light (energy), and smoke, which contains thousands of chemicals. Once it has started, combustion is a self-sustaining process that will continue as long as there is enough tobacco (fuel) and oxygen available.

When burning takes place, the temperature in a cigarette can rise above 800 °C at the tip. These high temperatures trigger the generation of more than 6000 different chemicals, many of which are harmful or potentially harmful. For reference:

Absence of combustion in PMI's heat-not-burn products

By eliminating combustion in our tobacco-containing smoke-free products, we aim to drastically reduce the formation of HPHCs. Our principle is to heat tobacco to temperatures low enough to avoid ignition and burning. We use heat control technologies to ensure that the tobacco does not reach the temperatures necessary for combustion to occur. This allows nicotine and flavors to be released from the tobacco, while generating lower levels of HPHCs, compared to cigarette smoke. Similarly, our e-cigarettes and other smoke-free products also do not burn tobacco because they either do not contain tobacco or they don't generate heat at all.

We've developed two demonstrations that clearly show the lack of combustion in our Tobacco Heating System (THS). The Combustion Demo uses nitrogen gas to show that a cigarette burns while THS does not. And the Aerosol Demo provides a closer look at the differences between cigarette smoke and THS aerosol.

There is a growing scientific consensus that completely switching to tobacco- or nicotine-containing products that do not burn tobacco has the potential to present less risk of harm than continued smoking for adult smokers who don't quit. Learn more about our smoke-free products, read an overview of what we've learned from our research on these products, or you can go straight to our publications library for all the scientific details.