Abstract
The present paper gives a balance of total water (comprising moisture content of tobacco as well as water of combustion) in the smoking of a plain cigarette without filter under standard conditions. 62.8 % of the hydrogen originally present in the burnt portion of the cigarette are transformed into water. The sidestream smoke is enriched by the total water to a large extent, i.e., in proportion to the total water of a cigarette, 14.4 mg of water are calculated to be transferred to the mainstream smoke and 344.7 mg to the sidestream smoke and to the ashes. 14.6 % of the said hydrogen are found to be delivered into the condensates of main and sidestream smoke in the form of slightly volatile compounds containing hydrogen. The residual 22.6 % are transferred into the gas-vapour phase in the form of volatile compounds. The interpretation of temperature measurements made along the axis of and in the space above a freely smouldering cigarette (without drawing) as well as the determination of the velocity (33 cm/sec) of the escaping sidestream smoke indicate the presence of a rapid and steep convection stream over the glowing zone. This finding accounts for the large water enrichment of the sidestream smoke and for the fact that water formed by the combustion process does not contribute to the transfer of steam-volatile substances into the sidestream smoke.