Tobacco Documents Online

- 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.