Mohammad Asghar ( Drugs Control and Research Division, National Institute of Health, Islamabad. )
Zaheer Ahmed Jan ( Drugs Control and Research Division, National Institute of Health, Islamabad. )
Nicotine, tar and carbon monoxide contents of tobacco smoke have been determined and reported under standard laboratory conditions by a number of workers. To control the level of nicotine, tar and carbon monoxide in cigarettes, variations made in the manufacture have reduced amounts of these constituents. In U.K1. during 1934-1940 the values of tar, carbon monoxide and nicotine per cigarette were 33, 19 and 2.0 mg respectively which decreased to 17, 17 and 1.4 mg respectively by 1979. In USA’, average tar and nicotine contents per cigarette in 1956 was 38 and 2.7 mg respectively which was reduced to 13 and 1.0mg in 1984. The contents of nicotine, tar and carbon-monoxide in tobacco smoke under standard laboratory conditions have not been reported for cigarettes available in Pakistan. This study was undertaken to determine nicotine and tar contents of various brands of cigarettes available in this country.
MATERIAL, METHODS AND RESULTS
Mainstream smoke analysis of 47 brands of commercial cigarettes was done using 8 channel Cigarettes Smoking Machine (Model SM—302 supplied by M/S Filtrona Instruments and Automation Ltd., England) provided by WHO. Puff and puff duration was so adjusted that a complete cycle lasted 60 seconds, giving a puff frequency of one per minute. Appropriate length of cigarette was smoked leaving butt length as indicated in Table I. The puff volume was adjusted to 35 cc. After completion of smoking, the Cambridge filters used were removed and disintegrated completely in methanol. The contents of tar and nicotine for each brand were determined by the method developed by International Standardization Organisation (ISO). Tar contents which were not corrected for water contents (1-2 mg), were determined gravimetrically while nicotine was measured spectrophotometrically using the following formula:
alkaloid (as Nicotine) mg/cigarette (259- A 236 + 282 ) X 1.059 X 1000 X 100 343x2x5 number of cigarettes smoked on C. F. disc.
Various parameters of cigarettes studied are shown in
Table I whereas Table II shows nicotine and tar contents (mg/cigarette) of some commercial brands available in Pakistan as measured under standard laboratory conditions. The tar yields of mainstream smoke of various cigarette brands varied from 16.3 - 66 mg/cigarette and nicotine content ranged between 1.2 to 4.2 mg/cigarette. Tar and nicotine levels in Pakistani cigarettes are higher than those reported from other countries (Table III).
Maximum limits fixed by legislation or by voluntary agreement by some of the countries (U.K., USA, Egypt, Finland) are 20 mg/cig arette: for tar and 2 mg/cigarette for nicotine. Of 47 Pakistani brands 41 had tar and 37 nicotine levels per cigarette above these limits. Considering the effective length of the cigarettes studied and with certain limitations it can be said that the cigarettes with filter tips have lower nicotine deliveries than ‘cigarettes without filter tips. The same trend is found in the case of tar levels. This may suggest that filter tip plays a certain role in retaining a part of the contents of these two noxious substances. However, evidently a significant amount of both tar and nicotine is inhaled by the smokers; as such the protection provided by the filters is of little consequence.
Of 47 brands of cigarettes in Pakistan, 87% had tar and 78.7% nicotine levels above the allowable international limits. The fact that some brands of cigarettes in the market deliver high levels of tar and nicotine shows that there exists no legislative control on the maximum permissible limits for these noxious substances in cigarettes and the manufacturers ignore the grave risks associated with high concentration of tar and nicotine in cigarette smoke.
The authors are grateful to WHO for providing Cigarette Smoking Machine. We are also thankful to Maj.Gen M.I. Burney, Executive Director, National Institute of Health for his encouragement and guidance.
1. IARC Monographs. Tobacco Smoking, 1986;38;60.