Benchmark Website

Covering Letter to the Department of Health

18 June 2003

Please find enclosed the Final Report of the 'UK Smoke Constituents Study'. As agreed at the outset, we will also be making this report widely available by publishing it on the TMA website www.the-tma.org.uk.

This Final Report draws together the information from a single point in time study of smoke constituent yields from a spectrum of cigarettes on sale in the UK. Results for specific groups of smoke constituents were presented in a series of interim reports from February 2002 to the present date. As requested in the original protocol, provided by and agreed with the Department of Health (DH), LGC [1] (subsequently Arista Laboratories Europe) has provided mean individual constituent yields for each cigarette brand in the study and regression analyses describing functional relationships between the constituent yield and both 'tar' yield and carbon monoxide yield.

This large voluntary undertaking by the UK-based Member Companies has been successful. It required considerable skills development in the independent LGC facilities, reflected by the timescale necessary to develop validated methods fit for purpose, even with considerable support from the Member Companies. The entire study has been conducted in an exemplary spirit of scientific co-operation for which we hope that due recognition will be given.

We are aware that other states and countries have carried out 'benchmarks' of their local cigarette brands' smoke constituent yields. However, the current study is unique in that it captures data across a range of the blend styles of cigarette available within the UK.

We are pleased to report that the UK benchmark study has fulfilled its prime objectives as stated in the protocol:

  • to determine the yield ratings of selected smoke constituents as identified by the UK DH in mainstream smoke for the selected cigarettes, in accordance with the agreed, validated methods; and
  • to establish the functional relationships between individual mainstream smoke constituent yields and 'tar', nicotine and carbon monoxide (CO) as set forth in this study.

The yield of 'tar', nicotine and CO and of 42 other less abundant smoke constituents was determined for 25 cigarette brands. The whole exercise has confirmed the utility of 'tar', nicotine and CO testing as required by the UK Government and EU regulation. However, since the yields of other smoke constituents are related to 'tar' and CO yields, the need to test them separately is questionable. This is similar to the findings reported from other "benchmark" studies. Furthermore, the cigarette tobacco blend style has some predictable influence on smoke constituent yield as reported in previous studies (e.g. the Independent Scientific Committee on Smoking and Health 4th Report 1988).

Nonetheless, we emphasise that the present study was fraught with difficulties even though it was conducted in an independent laboratory with considerable experience in cigarette smoking and testing. The major concerns include:

  • There are no internationally cross-validated standard methods to determine the yield of these constituents and some technical concerns have been documented in the methods used in this study.
  • The conditions specified in the standard smoking method used for smoke collection (ISO 3308) could not be rigorously adhered to when the range of trapping systems required to isolate specific analytes were attached to the smoking machines.
  • Many of the analytes are minor components of 'tar' and cannot, therefore, be measured more precisely than 'tar' itself. Therefore, the absolute yield values are less certain and the measurement tolerance must be greater, in some cases by an order of magnitude, than the ISO standard (ISO 8243) of 20% for a one point in time assay for 'tar'.
  • A snapshot sample tested in a single laboratory at a single point in time cannot provide robust estimates of smoke constituent yields and variability for a given brand.

The issue of measurement variability and its impact on uncertainty in absolute yields of smoke constituents and their measurement tolerances is complex and will only be touched upon here. Perhaps it is sufficient to state that there are several components of short-term and long-term variability arising from the repeatability of 'within laboratory' procedures, the reproducibility of 'between laboratory' testing, and the products themselves. All of these are recognised and addressed in the relevant ISO standards specifying procedures for sampling and testing. The current study can only report on short-term, 'within laboratory' variability.

If this matter were to be pursued further, these sources of variability would need to be quantified through collaborative tests to provide estimates of the overall measurement tolerances. This is part of the normal ISO process for standardising methods that has been used successfully in the past for 'tar' and nicotine yield measurement through ISO and CORESTA groups. A tolerance value for the measurement of CO and the development of methods for measurement of smoke nitrosamines and benzo[a]pyrene yields are currently under consideration by CORESTA and ISO subgroups which have 'appropriately qualified experts'.

Over many years the UK has established a leading position in developing smoking procedures and protocols for measuring smoke constituent yields. The work was originally intended to monitor the 'tar' reduction programme and subsequently to monitor compliance with the package labelling regulations, and it continues to operate very effectively. Because of the expertise and quality of the information generated, any problems with 'tar' and nicotine measurement in the UK have been successfully dealt with through a rigorous procedure, backed up by close liaison between LGC and the TMA Member Companies, through an expert committee – the Scientific Liaison Working Group. In addition, TMA and LGC scientific experts have worked with the British Standards Institute technical committee dealing with the testing of tobacco and tobacco products, and the corresponding ISO technical committee. It would seem expedient to continue to use these proven procedures to monitor the absolute measurement of any additional smoke analytes, should the need arise. However, as the results of this study have demonstrated, the yields of other smoke constituents are related to 'tar' and CO yields. This brings into question the need to continue to monitor the measurement of these additional smoke analytes. Member Companies continue to believe that the best way to make progress on the issues raised concerning cigarette testing is through discussion and their scientists would be pleased to meet with you and any scientific experts who may advise you to consider in detail the report and any related issues ...

[1] During the course of this study, the tobacco analysis section of LGC was taken over by Arista Laboratories, part of Molins PLC. With agreement of the DH, the outstanding portion of the contract was novated to this group, who agreed to meet and honour the standards specified therein.

> UK Smoke Constituent Study (PDF)

> Smoke Constituents Reports