At British American Tobacco Malaysia, we use a standard method, approved by the International Organisation for Standardisation (ISO), for measuring the tar and nicotine levels in cigarette smoke. However, there is currently debate about the usefulness of this method.
Tar levels are expressed using a simple equation:
Total particulate matter less water less nicotine = tar
Using the standard method, the cigarette is ‘smoked’ by a machine, which takes a 35 millilitre (ml) puff of smoke lasting two seconds, once a minute, until the cigarette has been smoked down to a point close to the filter tip. This standardisation allows the measurement to be done the same way anywhere and enables uniform labelling of tar and nicotine measurements on cigarette packs, expressed in milligrams (mg) per cigarette.
It has long been recognised that machines do not ‘smoke’ the same way as people do. People not only smoke differently from machines, but differently from each other, and the same smoker may smoke differently in different circumstances. A person can take more puffs or puff more strongly, or take fewer puffs or smoke less of the cigarette.
The ISO machine measurement gives a consistent, standardised way of ranking tar and nicotine yields amongst different groups of cigarettes, and we believe it can provide a basis for smokers to distinguish between different strengths and tastes. But the machines do not measure what smokers actually get from cigarettes. This means the ISO number does not indicate the actual number a smoker gets and, for example, someone smoking a cigarette labelled ‘5 mg tar’ should not assume they are getting half the tar of a cigarette labelled ’10 mg tar’.
The World Health Organisation (WHO), the US National Cancer Institute and others in the public health community have raised concerns about smokers being exposed to higher levels than the figures delivered by machine measurement, and are therefore concerned that the current ISO method for measuring tar yields is misleading.
These organisations report that smokers of cigarettes measured at lower tar by the current ISO machine method change their smoking behaviour to take as much tar as they would from cigarettes measured at higher tar. ISO has set up a working group, which includes representation from the WHO and various national standards organisations, to look at whether a better way of measuring can be found.
British American Tobacco believes that investigations into improving measurement are important and is discussing its filter analysis technique with this working group.