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Article | Aerosol Chemistry | Apr 4, 2023

Methods for generating and testing aerosol from THS

Cigarette smoke is produced when the tobacco in a cigarette burns at temperatures in excess of 600 °C. At such high temperatures, the tobacco is burned to ash and generates smoke that contains thousands of chemicals, including high levels of harmful and potentially harmful constituents (HPHCs) many of which have been recognized by public health authorities to be the most likely causes of smoking-related diseases.

The Tobacco Heating System (THS, commercialized as IQOS), on the other hand, heats tobacco without burning it to generate a nicotine-containing aerosol with significantly lower levels of HPHCs. It is an electronic device, and it generates an aerosol that is fundamentally different from cigarette smoke. For example, the aerosol of the THS contains about 80% water, whereas cigarette smoke contains only about 10% water. Because of these facts, some of the standard methods used to assess cigarettes cannot be applied and do not produce accurate measurements of certain aerosol constituents without modification. We provide the full methodology, including a detailed description of these modifications and step-by-step instructions for collecting the aerosol of THS using a commercial linear smoking machine.

You can find methods and protocols related to our assessment of THS aerosol in our publications library by filtering for "methods and protocols." A summary of the technologies that we use to analyze THS aerosol is shown below:

Close-up of two people in an office environment discussing over an smoke-free device.

Aerosol Studies

Aerosol studies are key to our smoke-free product research. They confirm that our smoke-free products don't burn tobacco and emit lower average levels of harmful chemicals. Learn more about it here.

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PMI's aerosol chemistry list of 58 constituents

We regularly monitor the levels of harmful chemicals. See which chemicals are part of the PMI 58 list.

Tobacco heating system's mainstream aerosol compared to reference cigarette smoke

We observed an average of 90-95% reduction of the levels of HPHCs in the THS aerosol.

A scientist in a white lab coat with transparent glasses holds a notebook.

FDA's list of HPHCs

See the levels of toxicants in THS aerosol compared to cigarette smoke according to the FDA-93 list.

Close-up shot of microscope with metal lens at microbiological laboratory.

Untargeted Assessment Strategy

See the methods and results behind our comprehensive, untargeted screening of smoke-free product aerosols.

Illustration of comprehensive chemical characterization of the THS aerosol

Comprehensive chemical characterization of the aerosol generated by the Tobacco Heating System

Untargeted screening further confirms reduced average levels of harmful chemicals in THS aerosol compared to cigarette smoke.

Close-up of a petri dish containing red substance, placed on a laboratory shelf.

Transparency in science to promote best practices

PMI shares state-of-the-art methods for smoke-free products assessment.

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Indoor Air Quality of Smoke-free Products

Discover the impact of smoke-free products on indoor air quality. Our research, conducted in controlled environments, reveals that the Tobacco Heating System (THS) aerosol has minimal impact on indoor air quality.

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Reduced Risk Products ("RRPs”) is the term we use to refer to products that present, are likely to present, or have the potential to present less risk of harm to smokers who switch to these products versus continuing smoking. PMI has a range of RRPs in various stages of development, scientific assessment and commercialization. All of our RRPs are smoke-free products that deliver nicotine with far lower quantities of harmful and potentially harmful constituents than found in cigarette smoke.