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Derek Irwin 03/12/98 09:25 To: cc; Subject: Richard Baker/Southampton/GB/BATCo@BAT Nicotine / tar ratio (NTR) - claim of trapping artefact effect at low deliveries At the SST, Kelley StCharles interrupted my explanation of why NTR increases in low delivery high ventilation products to give a rather amazing explanation of his own. He claimed that it was due to a pad trapping artefact. I did not get an opportunity to develop my own position, discussion moving on to other topics. I forgot about it until a discussion with Steve yesterday. I asked if we were sure that the dramatic reduction in water in particulate matter, observed with ventilated products, was due to combustion changes, or due partly to a pad trapping artefact. Steve explained that he was sure and gave me some results to prove it, reproduced in the attached Excel file, to which I have added NTR and WTR values. WTR is not changing with amount of tar on the pad, this being varied by smoking different numbers of cigarettes per pad. It also shows that NTR is not increasing when fewer cigarettes are smoked per pad, which think would be the case if Kelley were right. There are two reasons why NTR increases with ventilation. First, there is a "front end", combustion effect that increases NTR at slower flow rates even in plain cigarettes. Second, NTR increases when smoke passes through a CA filter and this effect is accentuated at slower flow rates which allows more effective trapping of semi volatiles such as water. I think the "front end" effect dominates but we may not have structured experimental results to prove this. ( Some of my recall is based on Gallaher experience of testing constant puff volumes but different durations etc., and we may not have comparable results.) I am a bit concerned that Macon and Southampton may be offering different explanations on this and other topics. I think one goal of the SST should be to reach agreement on such points, and that mainly involves getting agreement between Macon and Southampton because the other Centres have been less prolific in their output on such topics. I may communicate results in the Excel file to Macon in due course. NTR x Cigs smoked. 321154772

Highly ventilated Slim Plain King Size No. cigs TPM Water Nicotine NFDPM smoked (mg/cig) (mg/cig) (mg/cig) (mg/cig) to pad NTR (%) WTR (%) 3 1.19 -0.10 0.13 1.16 11.2 -8.6 5 1.62 0.01 0.17 1.44 11.8 0.7 7 1.52 -0.07 0.18 1.41 12.8 -5.0 9 1.60 0.01 0.18 1.40 12.9 0.7 3 9.32 0.83 0.71 7.78 9.1 10.7 5 9.38 0.77 0.72 7.90 9.1 9.7 7 9.47 0.72 0.74 8.01 9.2 9.0 9 9.04 0.86 0.72 7.46 9.7 11.5 3 15.34 1.31 0.92 13.11 7.0 10.0 5 15.94 1.28 0.95 13.70 6.9 9.3 7 15.67 1.39 1.00 13.27 7.5 10.5 9 15.55 1.30 0.99 13.26 7.5 9.8 3 19.77 3.32 1.26 15.19 8.3 21.9 5 19.65 3.30 1.29 15.06 8.6 21.9 7 20.03 3.48 1.34 15.21 8.8 22.9 9 19.58 3.31 1.31 14.96 8.8 22.1 NTR= Nicotine / NFDPM ratio WTR = Water ! NFDPM ratio 321154773