THPs are designed to heat rather than burn tobacco. The burning zone in a cigarette can reach temperatures of between 600 and 950̊C, whereas in THPs, the temperature is hundreds of degrees lower. It is high enough to release nicotine and flavourings but not so high as to result in the decomposition of the tobacco and the creation of high temperature smoke toxicants thought to be involved in the development of the serious diseases associated with smoking. These products therefore produce fewer toxicants and have the potential to be significantly reduced risk compared to conventional cigarettes.
Although various THPs are commercially available, they differ in the way they heat tobacco and in their temperature characteristics. Currently, there is no standard way of assessing whether a product is mainly heating rather than burning tobacco. So scientists at British American Tobacco have developed a 5-step approach to comprehensively assess this aspect of a THP.
‘To ensure a THP product really is producing an aerosol by heating and not burning tobacco, it is important to characterise its thermos-physical performance as fully as possible,’ says Dr Chuan Liu, Head of THP science at British American Tobacco. ‘Our five-step approach provides a comprehensive yet practical assessment irrespective of the heating mechanism in the device.’
This approach is described today at the Annual Meeting of the Society for Research on Nicotine and Tobacco (SRNT) in Florence, Italy.
Step 1: Measure changes in the physical and chemical properties of the tobacco (the type normally used in the device) as it is heated to THP operating temperatures.
Step 2: Using a thermocouple inserted into the tobacco, measure the maximum temperature the tobacco is heated to, and how long it is heated for when the THP is used.
Step 3: Analyse the levels of the following combustion products: CO, CO2, NO and NOx produced by the device when heating tobacco. (These are key markers for tobacco that is heated to high temperatures or burnt).
Step 4: Quantify emissions of a range of other known cigarette smoke toxicants potentially produced by the device.
Step 5: Examine the physical integrity of the tobacco rod after it has been heated in the device, to assess the extent of any degradation from heating to high temperatures or burning.
In case you missed it, Dr Chuan Liu's poster from the SRNT can now be viewed in the bat-science library .