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FIGURE 3 EFFECT OF VENTILATION ON pH OF SMOKE FROM CORESTA VENTEO•FILTER CIGARETTES Effect of Ventilation on Filtration Figure 4 illustrates the change in TPM with increasing ventilation. Less than 50% ventilation tion produced higher TPM deliveries than expected, whereas more than 50% ventilation resulted in lower TPM deliveries. This phenomenon is attributed to the increased efficiency of the filter as smoke velocity decreases (Table 3).* At low ventilation levels, filtration was not changed. At high ventilation levels, however, smoke velocity is reduced and high filtration efficiencies are achieved (Figure 5). ' It is surprising that the TPM reduction curve parallels the ventilation curve above 50% ventilation rather than ascend more steeply. One explanation for the observed result is that, at very high ventilation levels, the air entering the vents tends to force the smoke to the center of the filter, thus limiting the area of the filter available for filtration. 6 / t t

0 x TABLE 1 EFFECT OF 50% FILTER VENTILATION ON SOME SMOKE COMPONENTS Smoke Component Reduction, % CO y 58 HCN A ^ ' ' ' ~ 74 Acetone ~ 50 Acetaldehyde 46 Benzene 47 ^ Curnene 50 ^ Limonene 48 Phenol 23 Menthol ~ 26 Catechol 41 Nicotine 42 Dimethylfuran 26 FIGURE 1 EFFECT OF VENTILATION ON NICOTINE CONTENT OF TPM NICOTINE(100) TPM 8.8 8.6 8.4 8.2 8.0 7.8 9.0 r 0 - 1 --- 1 I I 10 20 30 40 50 VENTILATION, % 3 ~ 0 w ~ J v .. 0 w

11 TABLE 2 EFFECT OF VENTILATION SYSTEM AND DENIER PER FILAMENT ON PERCENTAGE OF NICOTINE IN TPM Tipping • Tow. Qen./FiI . Dilution. . % . TPM. rng Nicutine, InJ Nicotine (100) TPM 1• Line macro 1.8 49 6.2 0.50 8.05 1•Line macro 3.3 49--~ 8.5 0.64 7.50 ~ 1•Line macro 8.0 43 9.0 0.64 7.12 8•Line micro 3.3 42 10.0 0.75 7.5 Ultraporous 1.8 52 5.5 0.46 8.45 Ultraporous 3.3 47 7.7 0.64 8.28 Ultraporous 8.0 50 6.9 0.56 8.16 FIGURE 2 pH 6.4 6.2 6.0 5.8 5.6 5.4 5.2 5.0 1 0 EFFECT OF VENTILATION ON pH OF WHOLE SMOKE 49% VENTILATION / 39% V ENTI LATI ON ~ NO VENTILATION I 1 1 I 1 I 1 1 J 1 2 3 4 5 6 7 8 9 PUFF NUMBER 0 5

It would have been convenient if a 17.5-mL puff of 2-sec duration could have been taken through the cascade impactor. Unfortunately, the impactor design is based on the momemlum of the particles, and a fixed flow of 17.5 mL/sec must be used. The cascade impactor does not give clean separations of particle size; it is sometimes described as giving "furzy" lndica1ions of particle size. -A study should be made of the smoke particle size in smoke from vented-filter cigarettes by means of light-scattering or other techniques. FIGURE 6 EFFECT OF VENTILATION ON SMOKE PARTICLE SIZE 0 PARTICLE SIZE, p M 10 u CUtit:STA NO. 1 NO FILTER VENTILATION a CORESTA N0. 2 50% FILTER VENTILATION 1.00 H I ZN

I FIGURE 5 EFFECT OF VOLUMETRIC FLOW RATE ON FILTER EFFICIENCY EFFICIENCY, % 60r- 50 40 30 20 10 :0 ~0 ~J ~J J VOLUMETRIC FLOW, ML/SEC Effect of Filter Ventilation on Smoke Particle Size To the authors' knowledge, the effects of filter ventilation on smoke-particle size have not been investigated. The smoke particles !n a vented-filter cigarette travel at a lower velocity than those in a nonvented-filter cigarette. Therefore, the particles will have more time to coagulate, and the average particle size will probably increase with increasing filter ventila- tion. We assume that the aerosol particle concentration generated by a 35-mm puff of 2-sec duration is similar to that of a smaller puff of the same duration. The particle-size distribu- tion of smoke from vented and nonvented-filter cigarettes is shown in Figure 6. These data were obtained by means of a cascade impactor. Experiments were performed on two series of cigarettes that were part of the 1978 CORESTA collaborative effort on ventilation. The surprising feature in Figure 6 is the slight increase in the 0.25-pm particles with ventilation. The vented-filter cigarette smoke travels through the tobacco column at a reduced velocity, which should cause a decrease in the total number of smoke particles. In fact, given the coagulation rate (1 x 10-9 mL/sec) and the particle concentration of smoke, one expects a X 8

I ,a FIGURE 4 REDUCTION IN TPM BY VENTILATION REDUCTIOK IN TPM, % 100, s0 60 40 0 L ^0 !r) (~0 I 1 a0 t nf) VENTILATION, % I I x TABLE 3 EFFECT OF VENTILATION ON FILTRATION EFFICIENCY F i ltrat ion E f f iciency, % Cigarette Vents Open Vents Closed Ventilation, % of Puff A 42 41 17 B 55 53 27 C 71 60 76 tr 0 w co d v 0 v 7

i FIGURE 7 E EFFECT OF VENTILATION ON PARTICLE SIZE OF SMOKE FROM CIGARETTE WITH HOLLOW TUBE TPM,% 80 70 1- 60 50 40 30 20 10 0L 0 0.25 0.50 • CORESTA NO. I WITH HOLLOW TUBE  CORESTA N0. 1 WITH HOLLOW TUBE 156% VENTILATION) 0.75 1.00 i ....i i k..t.L .... ,j.h1 FIGURE 8 EFFECT OF VENTILATION ON PARTICLE SIZE OF SMOKE FROM A COMMERCIAL CIGARETTE TPM, % 70 r 60 50 40 30 20 10 0 0 0.25 • VENTS CLOSED • VENTS OPEN, 76% VENTILATION 0.75 0.50 PARTICLE SIZE, y M . 1.00 I ;.....» ...

A cascade impactor described in another publication was used to measure the particle-siTe distribution of smoke.6 Smoke pH was measured by the technique proposed by Sensa- baugh and Cundiff.7 Smoke particulate matter was determined by the standard CORESTA method, nicotine by gas chromatography, and semivolatile compounds by a method described by Baggett, et al.8 • - RESULTS AND DISCUSSION ~ L..~•....,...~..:::...~ w............ •... .. .. .......~.. .-.A.iw•....~. __-.C:.J~ Effect of Filter Ventilation on Smoke Composition Norman showed that ventilation reduces by different amounts specific compounds present in smoke.' Our intent is to show some effects of ventilation that might be useful in the design of vented-filter cigarettes. The data in Table 1 show the reduction of various ._.-.....~ ~._.. . ' . . _ . . . ~ ' _ . .. . . . . . . J . . t. . . i .. _ r . . .. . v .. . / ventilation were the only factor affecting reduction, each smoke component would be reduced 50%. The amounts of low molecular weight gases such as CO and HCN are reduced more than expected from ventilation alone. Several studies9''= have shown that when the velocity of smoke is decreased, as it is in vented-filter cigarettes, diffusion of low molecular weight gases through the cigarette paper increases. It has been reported that the amounts of many semivotatile compounds are reduced less than expected from ventilation alone.' The slower combustion resulting from ventilation permits more efficient distillation of these compounds ahead of the burning coal. Norman noticed the decrease with ventilation in efficiency of the cellulose acetate filter for phenol filtration. This might be the result of the • compressed temperature gradient resulting from smaller puffs which shifts the ratio of vapor-phase phenol is available for selected filtration. Another possible explanation is that the reduced amount of water delivered' into the smoke of the vented-filter cigarette lowers phenol filtration. Similar effects are noted for other compounds that are selectively filtered by cellulose acetate. Two additional compounds for which filtration efficiency is signi- cantly decreased by ventilation are menthol and dimethylfuran. The effects of ventilation on nicotine delivery have beeri studied by several investigators.'.' Nicotine is reduced by ventilation less than expected. This is illustrated graphically in Figure 1 which shows an increase in the percentage of nicotine in the smoke particulate matter with increasing venti- " latiort. Separate experiments in which small puff volumes (10 to 25 mL/2 sec) were taken indicate that nicotine is transferred to the main-stream smoke more efficiently as smoke velocity decreases. 2

I. /..-^'-... . s..•. .i.~ ..• .• . ...._~•...- ...n~..•... . . .~ ~. . --. . . _... ..~ y •...a...:.-...~.....~.....•.....w....w:..a..t.._ :r.......a.t•..•......~......_....:~..:~.«......~+..~ . y.:.. .u EFFECT OF FILTER VENTILATION ( ON SOME PHYSICAL AND CHEMICAL ~ PROPERTIES OF CIGARETTE SMOKE Gerald P. Morie and Madelyn S. Baggett t~.ia;..T:.:.:~3::5 Y.+.~-.C.:..w"ra.+...:.w.aiw. s:..a.r.-w ua: ~:,......:._. ~~. ~,.:.. ~.. c..:...... _................ _. Research Laboratories / Tennessee Eastman Company ;- Marketed by the following affiliates of Eastman Kodak Company EASTMAN CHEMICAL PRODUCTS, INC., Kingsport, Tenn. 37662 EASTMAN CHEMICAL INTERNATIONAL CO.. Kingsport, Tenn. 37662 EASTMAN CHEMICAL INTERNATIONAL LTD.. Kingsport, Tenn. 37662 EASTMAN CHEMICAL INTERNATIONAL A•O., Zug, Switzerlend :blication No. FTR•57 n*~, -.e. J O O 4,wt

I 20% decrease in smoke particle cor.centration.' Therefore, a corresponding increase in the mass of these particles, as shown in Figure 6, is expected. The change in particle concentra• tion that results from coagulation can be calculated from Equation 1. -1 - 1 - K t N No ' where N= number of particles per mL No = number of particles per mL at time 0 t = time k= coagulation rate constant (1 x 10-9 mL/sec). 0 No is assumed to be 4.4 x 10'a particles/mL (12). For an 85-mm cigarette, when the average velocity decreases from 35 cm/sec to half that amount, the number of particles decreases to 3.5 x 10-8 rparticles/mL. Thus an increase in the average particle size is ~,.,.~ . - . , , _ , ..... - ., (0.25 µm). A second experiment was performed to determine if a change in the particle-size distribu- tion occurs when a reduced puff volume of 2-sec duration is taken. A cigarette from the CORESTA-vented series was equipped with a hollow tube, and a second cigarette of this series was equipped with a similar hollow tube that allowed 50% air ventilation into the tube. The results of the vent-hollow-tube experiment are shown in Figure 7. A slight increase in the number 0.25-µm .particles occurred again. These data suggest that a broad- ening or widening of the distribution of smoke particles of this size occurs when a slow (17.5-mL) puff of 2-sec duration is taken. The average particle size also increases as expected. Recently Ishizu, Ohta, and Okada reported changes in the number of smoke particles and the average particle diameter with different puff volumes.j0 They showed that the average particle size increases, and that the particle concentration decreases, as puff volume decreases. Our data are consistent with the conclusion of Ishizu et al. However, these investigators did not show the entire distribution curve to determine if this widening in the distribution occurs with the decrease in puff volume. The effect of ventilation on the particle size is enhanced when a very high ventilation cigarette (78%) is analyzed. Figure 8 shows a widening of the particle-size distribution and a shift to larger average particle size. 9 ,