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- sTO~^~ 22_~6~-~-- _ _. _ .~,._~.~¢_ ~...._._...._...~ ~ n pu: ; ; -_ - ------------ ~`'--r--- - 3--------- CIGARETTES A LA CARTE or How to play with filter efficiency, filter dilution and expanded tobacco in designing low- and very-low-tar cigarettes. lgao

1 Foreword Cigarettes have changed a lot in the past decade. But they look as unobtrusive as ever, and rightly so, because there is no reason to draw the attention of the smoker to technicalities which might distract him from the pleasure he derives from his cigarette. The situation is different for people working in the cigarette business. Whereas the technical, people are expected to know how cigarettes are made up, the commercial people might feel that their expertise in other areas dispenses them from this obligation. This is not exactly true, at least not for marketing people. As they need new products in order to be competitive on the market, they can cope much better with their task if they are aware of what is inside the cigarette and the tipping papers. * ~ *

3 CIGARETTES A LA CARTE Cigarettes are destined to deliver pleasure and satisfaction, and nothing else. As, however, pleasure cannot be assessed by numbers, modern cigarettes also deliver substances, like "tar", nicotine, carbon monoxide (CO) and nitric oxide (NO). > Whereas tar and nicotine can be correlated with taste strength and satisfaction, carbon monoxide and nitric oxide do not contribute to taste. We might say that tar and nicotine are necessary evils, while the two gases carbon monoxide and nitric oxide are just pure nuisances. But in no instance should these terms "evil" and "nuisance" be taken in their literal sense: Even the strongest cigarette will not produce enough of these substances to do any measurable harm. About TAR and NICCTINE f Btocfz I TAR and NICOTINE mafze up cvha.t La caf.£ed the pa:L.t.i.cu.£a.te phase oA the smofze. Tlie.y behave the eame eoay .towaada Sit.tha.tion, d.i,£ution and .the e55eet o5 expanded tobacco. Whcit ('s 3aid about TAR ift •th.c:s b%cochu~ce 1b aCsu appeicabfe, .thene5oiLe, to NICOTINE.

5 There are many possibilities to influence the tar, nicotine, CO and NO deliveries of a cigarette. By far the most important single cigarette component is the tobacco blend and its chemical make-up. But for our purpose, we deliberately disregard all cigarette criteria but three: 1. The efficiency of the cigarette filter 2. The use of ventilated filters for smoke dilution 3. The inclusion of expanded tobacco into the tobacco blend. These are the principal physical cigarette-design tools used by Philip Morris in modern low-delivery (LTN) and ultra-low delivery cigarettes. About CARBON MCNDXIDF and NITRIC dXIDb CaAbon rnonoxide (CO) and nit%c.i.c oxide (NO) a&e gases. Toye.the%c they maFze up about 5 peneent o5 the matinstn.eam ~smofze votume. 7he.i t concen.t•ta.t•i,on in .the hmofze can be nedueed by 5ie.tea diZution. NO wif-.2 be ne.duced by the same ex-ten.t as CO. In -th.i.s bnoeh« te we do no.t neben .to NO. Bu.t you ahe nemi.iided .tjia.t what L-s 6aid about CO is appCicabee .to NO atso. N CJ9 O ~ N N .~ tD ~ a

7 Let's now look at a burning cigarette, as shown in Fig. 1. This cigarette is made up by the three key components: 1. The filler blend, which is assumed to have the same composition in all cigarette models to be discussed. 2. The cigarette paper, to remain the same as well. 3. The cigarette filter, whose efficiency we shall modify and through whom we shall dilute the smoke. The smoke withdrawn from the cigarette at itsmouth end is called mainstream smoke. The smoke produced by the smouldering of the tobacco between the puffs, and which leaves the cigarette at its coal, is called sidestream smoke. BCocf~ 3 Abou.t mach.i.ne-3niok.~ng v6 c~.ganettea Tarc, riieot.i.ne, C0, NO and o.then ciganette de.E•ive,ty "NUMBERS" a.e.m%cya neSen to MAINSTREAM SMOKE eon6ti-tuen-t6. They nepnehen.t the arnoke w.Ethdnawn 6n.orn the eiganet.te by a SAtdKING 61ACHINE_ Suelc a maeh.C'ne -takes a 35 cc srnofze votcune duniny 2 seeorlds once eveny 60 beconds unt-i.f an aln.eed but•t eength is n.eached. The .to-ta.e nccrnbcn& oS pu6bs .thxougtc the c.i.yane-tte is caeeed PUFF COUNT.

9 The burning cigarette is a rather complicated matter. In order to make things easier to understand, we decree, therefore, that our model cigarette delivers the same amount of smoke per puff, from the first to the last puff. Furthermore, we assume that the amount of tobacco burnt in one puff, is identical with the amount consumed by smouldering between two puffs. The latter assumption closely matches the actual situation. The former assumption is permissible because it leads to accurate conclusions despite its oversimplification of the real situation. The idealized cioarette is shown in Fig. 2. It is necessary to have a detailed look at the characteristics of this cigarette, and to keep them in mind for the steps that will follow. Please retain that in this cigarette 1000 milligrams of filler blend are actually burnt in 10 puff periods. As a reference for a real cigarette the corresponding criteria are shown for the Phil ip Morris Multifilter 100's (MPH). But you should forget this real cigarette in the Eorthcoming considerations.

11 . Looking now at Fig. 3, we find that in the model cigarette, 1000 mg of filler are burnt in 10 puff periods, i.e. 1000 mg = 100 mg in one puff period. 10 Since we assumed before that equal amounts of tobacco are burnt during and between puffing, we arrive at ' 100 mg = SO mg 2 for the filler weight burnt per puff, and at 50 mg also for the filler weight smouldered between two consecutive puffs. In Fig. 3, the grey zones symbolize the filler slices burnt during the puffs, and the white zones those filler parts that smoulder during intervals between puffs. - The model cigarette is assumed to be of the traditional full-flavour style. By decree, we determine that the total TAR delivery of the cigarette is 20 mg, and the total CO delivery also 20 mg. This is a reasonable assumption for such a cigarette. Since 10 puffs can be withdrawn from the cigarette, each puff delivers 2 mg TAR and 2 Ing CO.

13 Let's suppose now that this model cigarette is a real cigarette, with which an unfortunate marketing director is expected to face a market characterized by a growing low-tar cigarette segment. IIe urgently needs a low-tar cigarette in the same pack, and requests a 10 mg tar cigarette from the p-roduct development people. Going one step further - and one ahead of the competition he requests that the CO number be cut by half also. Having read (and retained) the lessons of blocks 1 and 2, he rightly assumes that nicotine and'NO - will be reduced by about the same extent. - Last but not least, he tells the development people that the new 10 mg cigarette should have the highest taste impact possible. B~ock 4 tdltat the manfte.t.i.ng diAee-tot iuantb Bning docun TAR 5nom 20 to 10 mg pe2 eigaa.ette CO 5%com 20 to 10 mg pe:e cigan.e.tte withou-t ehang.i.ng the -tobaeco b2end, the add i.tives, .the 5i.2#en ma.ten-i.a.2, the c.cga!ce-t-te papen and the 5o•tmat ob the c.c.gane-tte.

15 The cigarette development people can play with only two capabilities: 1. Increase of the filter efficiency 2. Introduction of filter dilution They started with filter efficiency improvement alone. 11ow this tool works is shown on Fig. 4 We assume that the filter retains 10 mg tar in the original full-flavour cigarette. If the filter were cut off this 20 mg cigarette, its tar delivery would become 30 mg. In order to bring the tar down from 30 mg to 10 mg, it is easy to conceive - at least in mind - a filter that picks up 20 mg of tar. Unfortunately, the price to pay for achieving the 10 mg tar objective is an unacceptably high resistance to draw (RTD) of the filter, and consequently of the total cigarette. But worse, as CO is not retained by any filter, the 10 mg tar cigarette would still deliver 20 mg CO. Ilavin~ not achieved their goal for two reasons: 1. No CO rcduction at all 2. Too high cigarettc RTD, the cigarettc-development people did not hesitate and tried the second tool on their list, i.e.

17 filter dilution, because they knew that 1. Filter dilution will reduce both tar and CO 2. Filter dilution will not increase but rather decrease the cigarette RTD. They hypothesized that a 50 percent filter di- lution will achieve a 50 percent reduction in tar and CO, and they based their expectations on the convincing illustrations of Fig. 5, 6 and 7. Fig. 5 shows the principle of filter dilution. As mentioned in Block 3, the smoking machine takes a 35 cc puff from the cigarette. Filter dilution is a device allowing a controlled volume of air to penetrate through the filter. into the mainstream smoke. Fifty percent dilution means that half of the 35 cc puff leaving the mouth end of the cigarette is actually air, the other half representing the 17.5 cc of (non-diluted) smoke entering the filter at its tobacco end. This means nothing less than a reduction of the actual puff volume - i.e. the volume drawn through the tobacco filler and generating the smoke behind the coal - from 35 to 17.5 cc. We learned from Fig. 3 that a 35 cc puff burns SO mg of tobacco filler. This is shown in detail in Fig. 6, which demonstrates also that another 50 mg of tobacco is consumed between two puffs. But this relates to a non-diluted cigarette.

t66hZZ l OSZ 50 % FILTER DILUTION FIG, 7 17.5 CC GENERATED MS SMOKE, I,E. ONLY HALF OF TO8ACCO IS BURNT . SMOULDERING: SAME AMOUNT OF TOBACCC IS BURNT AS IN NON- DILUTED CIGARETTE .0 %o

21 In the S0 percent diluted cigarette, nothing is changed in the free-burning phase between two consecutive puffs. As shown in Fig. 7, 50 mg of tobacco is consumed by smouldering. During the puff, however, the actual puff volume is not 35 cc as in the non-diluted cigarette, but only 17.5 cc. As a consequence, only 25 mg of tobacco are burnt in a puff. During a puff period - comprising one puff followed by the interval between two puffs - only 75 mg of tobacco will burn away in the 50 percent diluted cigarette, as compared with 100 mg in the non-diluted cigarette. Coming back now to our cigarette development- people, we are sorry to report that they unexpectedly failed in their attempt to achieve a 50 percent tar and CO reduction by a 50 percent filter dilution. Why? The answer is simple. They forgot to care about the puff count. The explanation is shown in Fig. 8. Since the cigarette contains 1000 mg of tobacco to be burnt, but only 75 mg arc burnt per puff period, the puff count increased from 10 in the non-diluted cigarette to 13.3 in the diluted ci~arette.

23 a They actually achieved a 50 percent tar and CO reduction PER SINGLE PUFF, bringing the per-puff deliveries down from 2 mg tar and CO to 1 mg tar and CO. But for the total cigarette the delivery is 13.3 mg tar and 13.3 mg CO. The reduction was not 50 percent as expected, but only 33 percent for both criteria. The TASTE STRENGTH, however, suffered a reduction of-50 percent, as taste is being perceived on a per-puff basis. 8tock 5 Abou.t taste .6thength and numbehs - Taste atn.ength ia peneeived pen pu55. - DeCiveky numbeics ane nepon.ted pen eiganette. rhete5one, bon, a gEven .tan numben pen eiga:ce.t.te: - Taste a.tnength ts .fneneased ti5 the pu6b count ~s &educed; on - I S we ineneaa ethe pu5 6 count, we too6e .tas.te stnength. That's the end of the story. Both attempts to reduce tar and CO by half had failed. They had to fail, because the cigarette-development people lacked the very capability without which filter dilution does not lead to really satisfactory low-delivery products.

25 This tool is expanded tobacco. Expanded tobacco is presently available to Philip Morris and one other major cigarette company only. Expanded tobacco (ET) is a commodity that burns like normal cigarette filler, with one notable exception: A given weight of ET fills twice the volume of the same amount of normal tobacco filler. This is illustrated in Fig. 9 Suppose now that we can build a cigarette which is made up in slices of equal length, i.e. of equal volume, filled alternately with ET and normal filler. Our model cigarette will have a total of 20 slices of 0.18 cc volume each. The odd-numbered slices 1 to 19 shall contain 25' mgtT each and be destined to burn during puffing,-i.e. to produce mainstream smoke. The even-numbered slices 2 to 20 shall contain S0 mg normal cut filler each and be destined to smoulder between the puffs. If our cigarette were fitted with a 50-percent diluted filter, we could actually observe to happen what we expected: Each time the smoking machine draws a puff, filter dilution will reduce the actual puff volume from 35 to 17.5 cc, but since the puff will act on a segment of ET filler, a full slice volume of 0.18 cc will be burnt. Between two puffs, twice the weight of tobacco filler will be consumed, but since this filler is not expanded, the slice volume is also 0.18 cc. The total ciaarette will burn down to the butt in 10 puffs and deliver not more than 10 mg tar and 10 mg CO.

27 The problem is that such a cigarette cannot be made. But let us postulate that we do not need to separate ET and normal tobacco filler in order to achieve the desired result. The goal of reducing by half both tar and CO would then be reached by combining 50 % filter dilution with a cigarette filler blended from equal volumes of ET and normal cut tobacco. Such a cigarette is shown in Fig. 10, from which it is easy to understand that the 1: 1 volume ratio corresponds to a 1/3 : 2/3 weight ratio between ET and normal cut filler. ' The total tobacco filler to be burnt adds up to 750 mg. Since one puff period consumes 25 mg (during the puff) plus 50 mg (between the puffs) = 75 mg of tobacco filler, the cigarette will burn down in 7 = 10 puffs. This is exactly what was intended. The proof is made, therefore, that the combination of filter dilution and a blend of ET and normal cut tobacco leads to the desired goal. It is even possible to derive a general rule, which is explained in Block 6. Stocfz 6 Ru.Ce o 5 -thumb In onden to heduce TAR and CO by X o wi.thou.t changing the PUFF COUNT - difu.te the 5it.ten by X % and - neptaee X$ 06 the 5-i.Qten votume by ET N ~ O ~

29 In order to make things clear, Fig. 11 shows how the goal has been achieved: A is the 20 mg tar cigarette from which we started. This cigarette delivers 10 puffs containing each 2 mg tar and 2 mg C0. Cigarette B is different from A only in that its filter is S0 percent diluted. Consequently, tar and CO are reduced from 2 to 1 mg per puff. Conclusion: Filter dilution controls the smoke delivery per puff. Second conclusion: With filter dilution we loose control of the puff count. In cigarette C we use ET as a filler component. This allows us to reduce the puff count from 13.3 (cigarette B) to the original 10 ' (cigarette A), all by maintaining the per-puff advantage gained by filter dilution. Conclusion: ET in the filler blend controls the puff count. Fitten ditut.fon and expanded tobaeco These two .Lndispensab.2e toot6 6on B.Coch 7 design.i.ng tow-de.fiveny e-i.ga&et#es ane bes.t ehanacten.Lzed as 5oQ.2ows: FILTER DILUTION contnots smoke numbens PER PUFF. EXPANDED TOBACCO in the 5ti.E-Cen btend con.tnots the PUFF COUNT.

31 Epilogue l Filter dilution and expanded tobacco are only two among many capabilities used for cigarette designing. Their contribution to cigarette development is invaluable, however. It can be said without exaggeration that without these two tools it would not have been possible to design the low- and ultra-low-tar cigarettes upon which the cigarette industry has to rely in order to safeguard the future of its business. To-day, only RJR and Philip Morris have their own technical process for expanding tobacco.' The other companies are compelled to develop the same or equivalent capabilities. The lead time for RJR and Philip Morris is not more than about two or three years. The Philip Morris brands of the future will have to be established on the markets within this very short period. If the people who develop, produce and market the Philip Morris brands are successful in their enterprise, the outlook will be quite bright for the Company. MAII/CI-fS/July 17, 1980 J