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j C t 2tv ) W G-to r.1 , 16'9 . 59s TOBACCO JOHtIS'OV: li ASSOC: OFF A:V:*L. CHEM. (VOL 69. tit): 4. 19t6)I Development of Machine Smoking Parameters for Measurement of Cigarette Tar Yield in the. United Kingdrom JOSEPH C. JOHNSON Lnrperial'To'bacco'Lrd, Process Research Servlces, PO Box 241; fifartcliJ~'"e, Bristol, UK BS99 7UJ The sarokiet and analitkal lmetbods used by sorertuoent.anditobaoeo tndustrf laboratorM1es an 7Ae result of many .•ears o[ coGaborati.e'work within tlsrindustrs and through International'bodka:wcb'asahe,Inter- oatiood Standards OrYanisadon. , Receotly; some pub(katkns hae r eritJcized l the .atldity and adenti5c soundness of these proceduret: It h shown that suek:critlelsats are totally unfounded byresie*rin= tbc work that led to tbe adoption of the current technique. Tar tab1ea, pubtisbed b7'the UK Healtb Depantments are .atid lo ranliicg brandl In orderofitLeir'lidds, wbik;aotaecessarnly reEecHtlg theabaolutt tar deliter7 to the taooker. Tbese tablba:are Intended ito and do pno.ide a relevant guide for smokers about the proportional tar yields of C'TC cigarettes. In 1973 the'Health Departments commenced the publication of a tar table, comprising tar and'nicotine )tields of commer- cial cigarettes in the United Kingdom: These tables were intended to rank cigarettebrands according,to tbeir tar dtliv- ery as a guide for smokers. Generating these tables required the standardization of smoking machine parameters and methods used to measure tar yields. Criticism has been expressed about the choice'of these parameters and methods and whether, over time, they are relevant to today's com+ mercial products (1-3). Theobjective of this paper is to~eon; ; solidate and review the historical development6 from the'fust' published data in 1933 (4), of machine parameters and meth- ods and demonstrate their relevance to current tar tables and brand ranking. The' smoking andl analytical procedures are well dot:u- mented{'S, 6) and their scientific validity has been established by exhaustive eoilaborativetesting„particuiarlyinthe United Kingdom over the last 13 years: The factors influencing the tar }ield obtained by machine-smoking a cigarette-puff ( parameters, butt length, smoke trapping system, and'smoking machine type-have been the subject of internationaidiscus, sion leading,to agreement on standard smoking regimes (fl); These test procedures have been adopted byof6cial'organi- zations such as the Laboratory of the Government Chemistt in the United'.Kingdom. Theseorganizations, while realizing that the testidoes-not necessarily indicate the amount of tar the smoker receives, appreciate that it does sensibHy andi reproducibly rank cigarettes in'.order, of tar delivery (8). The standard smoking machine parameters are 35 cu. cm pufCof' 2 s duration taken once per minute. Discussion Puff Panamerers Some,of the firsti workers to attempt to define a standardd puff volume were Pfyl and Schmidt (4I)lin 1933. From mea- surements made on 7 different smokers, thcy recorded a mean : puff volume of 40 cu. cm of'2's duration, taken tmice per minute. In 1!936; Bradfordl Hnrlan, and f9anmcr(9), .aorking in the l: niacd States, recognieed the need to establish a set of st:;n- dard smoking,conditions. Bradford ;,ndlhis colleacucs anbi- F..... -„ W...r~.4 trart7y sekcted'a35'cud cm ipu8'volume of 2 s duration, taken once pen minute, probably due to the technical Ilirnitations of their smoking,machine. In 196'l6observations were made on'312 UK smokers by Research Services Ltd on behalf' of the Tobacco ytanufac- turers Standing Committee. The average values for one cig. arette type were found to be 14' puffs, 12 min burn tiate,a frequency of'1.17 puffs per, minute, and a butt length of 1$' mm. When the same'cigarettrty,p,e was smoked on aunachine it was found that a 25' cu. cm puff volume of 2 s duration taken once per minute gave an alight time of ('2 min and a butt kni 18'mm (10). TF.ese parameters-a 25 cui cm puff, of 2's ditrationtaken once per minute-wereeonsidered to be realistic and were adopted'as the UK standand! During the same time period some other, countries had standardized on the 35 cu. cm puff, although a 40 cu. cm puff 'was used inn the'Federal Republic of Germany and Romania (11). In 1'969, on the inidative of the Getman'.Standards Institute (DI~~T)„ an International Standards Organization Technical Committee on Tobacco and Tobacco Proditcts was formed (7). One of the first actions of this group was to recommendd the 35 cu. cm pttB'volume of 2 s duration taken once per minute'as standard-largely'because'.most of theparticipatingg laboratories had a substantial amount of data based on this regime. Following on fromi market research studies initiated by I'mperial'Tobacco Limited (Tobacco Research Council i(1970) Document H1165, unpublished studies) between 1966 and 1970, the United Kingdomchanged from a 25 to a35 cu, em puff. This increase in puff~volitme proditced Ino change in the ranking order of' cigarettes ([mperial Tobacco Research I)epartment, unpublished'res'ults): Since 1970, studies of human smoking have been under- taken with puff volumes 6ting measured idirectly using some form of puff profilio device (12). Puff volumes and durations in the range 32.8 to 53.4 cu: cm and 1.53 s to:T.77 s, respec- tively, have been:reported fromithese studies (I13, 14')1 The rangein human puff parametersireRects the variation in smok- ing habits between indiividuals and the variation seen in the individual smoker,. The currently, accepted parametera lie within the range for humamsmokers. Changes in the machine smoking parameters within such limits (15); if appliedlto all brands would not alter the ranking oflcigarebte brands asgiven in the Government's tartable: Brrn Lengths The lencth to uhichia cigarette is smoked is animportant factor in determining thr,y,icW of tarand nicotine. Studies of the buttlrnsth left by smokers have,bccn cartied'out,in many countriesandldata firom these studies have been summarizcd by Wyndcr andiHofftrtann (d 1'). Based on these studies, the International, Standards Organization Technical Committce (7i k,s rc,:omntcnJcd a vtand.rrd hc,t Itintth ,,f '_I mm for phin cic:.rcttrs :ir.d a Icn,_th uf ,prr p!us 3 mmifor 1;! _,,-t:, _J ,.- .....^, 201~8397662

f: 7GBi.\SOS: ). A'SS'OC. OFF. ANAL CHEM rS'OL. 64. >rT a, Table .1. Compartson of sclqarana .tYp.a amok.d on 20~clsanne7 1lnearr smoking machthe and on rotary amoklhp mectWw' Ciprre^a tyw 20-Channel'macn+ne ~ Rotary macnine A~ 2s~a0:6t)i 22:7~(:: 1:16)~ B t'8s~.(.c~.0~.79)i 16'.7 1.01) ~ C 14.4 (_ 0:90)' 13.1 0.74) o Ya (_ 0ao) 6:4(r 0_46) E 4.5i(c 0:u) 4!3(_ 0:15) •s4 mm diameter glass tiber traps used on both machinp. S'cqarettes smoked into'traps. Results are eapressed nimp dry,condensate per cigarette. The mean and standard deviations were calculated from me.n vatues of 4 laboratories taking iMrt itn study. Tl.ble t. Compartson of S idQarette types smoked on 20-chenrnl Ohear smok/np machhhe and on b4hux»t 0neer'smoktnp mach'Ine" Ciqarette Rype 20~Channel machine ti?Ghannel'machine A' 25'.n( c o.EB)' 23.3 (- 1:40) B 1e31(c 123) 16.Di(n t:60) C 14.sI(r_ 045) 12:6I(n 1.3t)' 0 6:9i(= 1.20) 6.2y= 1.24) E 4:S (_ 011i2) 3:9 i( c 0:Sti) •44 mm diame.er glass fiber traps used'on both machines:5 cigarettes smoked into traps. Results are expressed as mg dry tondensate per eiyarette: The mean and standard devia•.ions'were calculated from mean vatues ot'3 laboratories taking part in stud)y. It' is generally recognized that smokers in the United King- dom smoke plain' cigarettes to a shorter butt length than, 23 mm. There is also evidence to show that theyy smoke king size and htmury'length cigarettes to longer'butt lengths (N.O.P. Market Research Ltd ('1967) survey to measure the London average length of'unburnt cigarettes,,unpub6shed results). Tli.erefore,,in the United Kingdom, cigarettes are smoked to butt lengths asagneed'between the Tobacco Research Counctl' and the UK Health Departments in 1972 (16). These are (a). 20 mm for plain cigarettes, (b) tipping paper, plus 3 mm for filter cigarettes equal or less than 75' mm, and'' (c) tipping paper plus 5'tntn forfi)ter cigarettes longer than75' mm, with the minimum butt mark on any cigarette being 2(D tnat. Smoking Machines vlany' attempts have-been made to develop equipment capable of smoking',cigarettes in a reproducible fashion, with references to constant suction s'moking,derices first appear- ing in the scientific literature in 1903 (17). Bradford and his co-workers in 1'939 (9) were among the first to realize that smoking machines would'fall, principa)ly, into 2 classes: (a) eonstant, volume machines using a syringe or metal bellows to produce the required pulf;,(b)constant floµ machines fitted with automatic timing devices to allow the required puff parameters to be generated at the smoking,port. Bradford also recognized that the 2 principles emp)oyed in, producing the puff wouid'give rise to 2 di&rent puff profves (plot of flow rate agains't'time): The,constant.-olume machine should produce a"beil-shaped""profile which approximates that'of the human'smoker whereas the constant flow• machine would produce essentially a"sqpare-Kati•€" profile: Machines constructed since 1'950 have been bas'edlon one orthe'other of'the 2lprinciples detailed above. Constant flow machines are now rarel, used and 2 types of constant volume machines have dominated the market'for many ycars: (a)'Linear simultaneous smoking machines such as tihr '0-channel machine: proauctd by Phipps andi Bird ini America t% hich uas based on a des'iEn b} Philip \'tbrris, This machine is nnw manufactured in the Uniticd Kingdom by . Filtrona,l'nstruments and Automation Ltd and is knou,n as the Filtrona 300. A smaUer 8-channel linear simultaneous machine(the Filtrona 302) iis also available: (bt Rotary'smok- ing machines of which the RMLsO CS built bh H. Borgw-aldt (West German!)), is the most popular. The R,C120 CS' is a devel opmentof an earlier Borgwaldt'rotary, smoking machine which had been basedlonlhe constant flow principle. As a, result'oPan'innovation made by Phipps and Bird i in America in ithe early part of the 1970s, all machines mentioned in ('a)'and (b) above have been modified to collect'and measure . carbon monoxide in addition to the productioniofcigarette tar. The Filtrona 300 is currently, used by the Laboratory of the Government Chemist toiproduce tar'yields and'is'the standard ana)ij-tical machine in many countries. The RM2p CS is the standard machine iniGermany andiis gaining popularityy espe- cially in Europe. Although the Filtrona 30D, the Filtrona 302, and the RUNi20 CS smoking machines give slightly differencmeanvalues for a given cigarette brand; the'precisionof'measurement obtained from the 3' machines is not signittcantly different (18', and Tables I and 2): AU these machines arc capable of a precision and reproducibility far in advance of any smoking machine constructed before 1950. Smoke Trapping Systems The 4 methods for the' collection of' smoke condensate which have been employed by analysts w•orking'in the tobaccoo industry tme jet iistpactiontrap: cold trap, electrostatic trap,, and' Cambridge filter trap. The jet impaction trap has been' described'by Mathewson (19). Its main use now is to collect' condensate from a large number of cigarettes for biological - as'say purposes. The cold trap (I1p„11) has been successfully used for the large scale collection of condensate for research purposes and for the routine estimation of smoke yields on small num+ bers of samples. However, cold traps are unwieldy'in usrand are not aconvenient'method of smoke coUection when a large number, of'individual tests are beingcondircted. Electrostatic precipitation i has been used to collect parti- culate matter by a number of tobacco laboratories, panicu- larly in Europe. It has the advantage of compactness. How, ever, to s'ecure' complete retentuon of, particulate matter, a high precipitator voltage (10-25 ~ kV) is necessary and' under these circumstances the butt end of the cigarette, unless sufficiently grounded, may become hig}t)y charged- Ifthe butt does become charged, smoke is deposited in the butt and filter tip rather than in the coUectibn tube. The'co)lection of s'moke'particulate matter on a Cambridge (glass fiber) filter was originally devcloped iin the'U•nited'States in, 1959 (20). Ogg (21) found that res'ults for the collection of Tab1e 3. Comparlson of'S clg.retta types smoked'k+to glass fiber and electrostallc traps• Cigarette type Gtassfiber trap Ekctrostnrc .yoe A 22'8'(- 066) 21.8 (,c 0191 g 170(= 0 66) 15'9(_ 084) C 138(c 0.54), 126(_ 0491 0 6 9( c 0 40)' 6'.1 (= 0201 E 48!_049) 4.31(=0371 . •9otligtass:fiberlraD(42mm diameler) and etec-ostetic trar•.r-e-e Mted to ro!ary smokng mac'-.,ne 20 aflarertes smo+cec mto traps Res::n5 are erpresseo as mg ory oondensawper cigare:te Tne mean ano scanoaro dewiat~ons.were caicuia:ed t.om meanwalues oi T(at) orafones:aR.ng part ins7udy,

600 JOt{NSONi 1:,ASSCX. OFF. .a1`AL. CHEM. (VOL. 69; NO:,4; 19l6) Tabtu !: Cempartson of tarcoll.ctbn on 44 mm dtameter and 22 mm dl.matNr ytaas nb.r'n[tNS' Ci9arette typa N mm diam, trap 1 92 mm diam. trap A 2ras(,o,1.091 22:a(',a~0.74)~ e t7:2(= o,es) t6:a(x0so)~ c' tD:r(s,o1>C) 19:r(,=:o.S41] i 0 6:f'(t 043) E:9i('a,0A,qi E, 4i6(';t 0:46) 4.7 'I= 0:JQ)i 'Bbth 44 mm diameter trap and 92 mm diamat.r'trap wara hnW to rotary smoking machine. S' ci9aranas wera smokad onto N mm diamaterpad: 20 cpar.nes wara smoked onto 22 mmidumetar pad. Resutts are ~e><prossrd ias mS ory cond.nsata par cigarette. Ttsa mean and'standard deviations wera calculated from mean waluer o(!9. IaDoratorits taking partin studjr. smoke particulate matter by glass fiber were very reproduc- ible„ and both intta- and interlaboratory, coefficients of vati- ((, ition were low., Comparisons of tar collection by the etbctrostatic.prta:ipi- tator and the glass fiber filter have been made (18, 21, and Table 3). Comparisons have also been unade between various diameters of glass fiber trap using'dif'ferent cigarette loadings (Table 4). The data show that for the same cigarette drandd the electrostatic trap gave a mean tar figure up to 10Ja lower than the glass fiber trap. This is due to the "charged" butt effect noted above. Glass fiber traps arc in good agreement irrespective of the diameter of the filter or the number of cigarettes smoked. Although the' electrostatic precipitatoris in regular use in West Germany and is occasionally used in some other Euro- pean countries, the glass fiber filter is preftrred'in the United Kingdom and by the majprity of other countries. Coeciusion Current procedures for the determination of cigarette tar yields are the result of continual development since 1933. Smoking machines which'started off as simple hand-operated devices have been developed into highly sophisticated, multi- channel, semiautomatic machines whichioperate to interna- tionally agreed'. standard smoking parameters. The smoking, parameters lie within the range found for human smokers. The use of these machines toge:therwith reproducible ana- 1yTical methods for the measurement oCtarand nicotine pro- vidcvalididatia to rank current brands. Acknowledgments The author gratefully acknouledges the assi'stance of D: T. Westcott (Imperial Tobacco Ltd) in the preparationof'this paper. He is also indebted to other member companies of'the Tobacco Advisory Council, namely, British American Tobacco Ltd, Gallaher Ltd, and Rothmans (R;i K) Ltd, for their helpful comments and'eriticism. REFEttENCtsS (1) U.S. Department of Health and';Human Services (19E4) Reporrt' of U1S. Surgeon Geaxral, •'Chromic Obstructive Lung' Dis. ease;" Rockvdle, IhD, pp. 335-337' (2)' Hartiman,E. (1983).Vrw Sci. Oct. .0, p. 159 (3) Weeks, D. Ji, #' Todd, S. P: (I983),'Vew Sci: Aug. 111. p. 431: (4) Pfyt, B., 3 Schmidt, O: (1933)'Z., Uhters: L.ebensnr. 66; 501- 306 (5) Bates, W. W.,,Giiffiths. R. B.. Harlow. E. S:, Senkus, K:, & Wakenham. H. (1968) Tob. Sci. 12,19.-196 (II RothKUll. K., A Giont, C. A. ('Eds) (1974) Standard Methods for the Analrsir of Tobacco Smoke. .nd Ed., Tobacco Research Couna7, London. UK. Research Paper, 11 (7) International Organizatiott, for Standardization. ISO Stwidard 3308 (Smoking Machine, Glass Fiber Filters): ISO Draft Pro- posal 4387 (Electrostatic Ttaps), working paperts of ISO'-TC'126: )ti301.N302,N303 (8) 1 Coktaan. R. F. (1981),1111 Sci. Nov. 3.,P. 369 (9), Bradford,J: A:. Hartan, W.,R.. & Hanmer. H. R! (1936) lnd. Eng. Chem. 28,836439 (110)' Bentley,,,H. II Burgan. l. G: (1%1).Ciyarerre Smoke Con- densarec Prepararion and Rourine Laboratory Ertintarion; 2nd Ed., Tobacco Vlartufacttuors Standing Comminee, Londoni (: K, Research Paper 4 (111) Wypder, E.1... & Hoffinann, D. (1967) inTobacco and Tobacco. Smoke Studies in Erperi+nentar Carcv+openesit. Academic Press. New Yark, IrY. pp: 8.t-I32 (12) Adaan: P. 1': (1966) "Nfeasurements on puffs taken.by human smokers," 20th Tobacuo Chemists Research Conferencc, Win= ston-Salem, NC (43) Adams„P. L(1976) "Changes in personal smoking habits brought about by changes in cigarette smoke yields," Proceedings ofbth International'Seience Consress, Japan Tobacco and'Salt Public Corp., Tokyo. Japan, pp. 102-108' (ht) Creighton, D. E., d LeKis, P. H. (1978) SmokiRg Beha<<iovr- Pkyaioloyicaf and Pn•elwlog•icaf Influences. Churchiti Livin;- stone,,Edinburglt, Scotland, pp:,289-316 (15) Rickert. W. S.. Robinson, J: C., Young, J. C.. Collishaw, N. E:, & Bray. D. F: (1983) Prer. yli 12, 682-696' (16) Repon of lhe Government Chemist (1973) "Smoking and Health," Her 4lajesty's Stationery'Officr, Londonl (1'K, p. 86 (117) Pbntap; Jl (1903) Dear \aAringriGerrrsseim (IBrrtin) 6, 673 (118) Timm. D: J. (1982) "Evaluation of the Collaborative Study on Smoke Analysis." International'Onganization for Standardiia- tion, Geneva; Sxit¢ertand! ISO~TC'1_6 Working Document \_90. (19) Mathcwson„H. D. (1968) Tob. Scii 12, 41-t9 (20) Warnman, W. B.. Jr, Cogbill, E. C.. & Harlow; E. & (1939)~ Anaf. Chem. 31, 1705-1709 (21) Ogg. C. L. (1964) ,l, Assoc. OJJ. Atric: Chrm. 47, 35'6•-36'2