Motohiko Muramatsu

Estimation of personal exposure to tobacco smoke with a newly developed nicotine personal monitor.

To evaluate the actual level of exposure of nonsmokers to tobacco smoke in their living environments, a convenient personal monitor of nicotine specific for tobacco smoke has been developed. The nicotine personal monitor consists of a sampler tube containing 450 mg of Uniport-S coated with silicon OV-17 and a portable sampling pump with a mechanical counter for obtaining total sampling volume. Using the personal monitor attached to a nonsmoker, ambient nicotine was collected in the sampler tube by drawing environmental air at a constant flow rate for a maximum period of 8 hr. The collected nicotine was desorbed by heating and directly transferred onto a GC column with a carrier gas. The amounts of nicotine inhaled by passive smoking in various living environments were estimated to be in the range of 0.9-40 micrograms/hr. These levels are equivalent to those from the active smoking of about 0.001-0.044 ordinary cigarettes in 1 hr.

A mathematical model of evaporation-pyrolysis processes inside a naturally smoldering cigarette

Abstract A one-dimensional mathematical model for heat and mass balance has been proposed to elucidate the changes occurring in the temperature and density of the evaporation-pyrolysis zone in a naturally smoldering cigarette. The model considers: (1) pyrolysis of tobacco obeying Arrhenius kinetics, (2) evaporation of water from tobacco following a mass-transfer- and rate-determined process, (3) weight loss of tobacco due to pyrolysis and evaporation, (4) internal heat transfer characterized by effective thermal conductivity, (5) heat loss attributable to free convection and radiation from the outer surface of the cigarette and endothermicity of the evaporation process, and (6) smoldering speed. These processes are expressed in a set of simultaneous ordinary differential equations that can be solved numerically by the Runge-Kutta-Gill method. The calculated distribution profiles of temperature and density in the evaporation-pyrolysis zone approximate the experimental results measured using thermocouples and a β-ray attenuation technique. On the basis of the model, the influences of several physical parameters on the shapes of the temperature and density profiles are predicted.

Estimation of personal exposure to ambient nicotine in daily environment

SummaryTo evaluate the actual exposure level of nonsmokers to environmental tobacco smoke (ETS) in their daily life, the exposure level of ambient nicotine was measured with a nicotine personal monitor carried by a nonsmoker. Average exposure levels of nicotine, even in such smoky places as cars, coffee shops and pubs, were less than 45 μg/m3. As a result of all-day monitoring, the highest amount of nicotine inhaled in a day was estimated, in this study, to be up to 310 μg, equivalent to actively smoking 0.31 ordinary cigarettes.

A Study on Precursors of Nitric Oxide in Sidestream Smoke

Abstract By a method of thermal analysis and smoke analysis of cellulose cigarettes treated with various nitrogenous compounds, it was found that nitric oxide in sidestream smoke is formed not only from nitrates but also from amino acids and water-insoluble protein, while little of the nitric oxide in mainstream smoke is formed from these organic nitrogenous compounds.

Kinetics of Oxidation of Tobacco Char

Abstract In this paper, thermal analyses (thermogravimetry, TG: derivative thermogravimetry, DTG: differential scanning calorimetry, DSC) of the tobacco char left after pyrolysis of tobacco shreds were carried out in a nitrogen atmosphere containing given amounts of oxygen under a linear heating or an isothermal condition. The principal object of the present work is to obtain apparent kinetic parameters useful in predicting the overall rate of the tobacco char - oxygen reaction. The TG-DTG-DSC curves obtained under linear heating conditions showed that the oxidation process of the tobacco char apparently consisted of two main steps ( I and II), which were independent of each other. Assuming that a uniform reaction model based on reaction rate - determined processes could be applied to the tobacco char - oxygen reactions in both steps, the oxidation rates for both steps were determined. The results showed that the oxidation rates of both steps could be expressed as: The values of activation energies, E, and pre-exponential factors, Z, for the oxidation reactions in steps I and II were found to be 19-21, 33-40 kcal/mol and 5.9 × 105-5.7x 106, 5.5 × 109 4.5 × 1011/ min atm1/2, respectively. Nomenclature As reactant (solid phase, tobacco char) E activation energy [kcal mol-1, 1 cal = 4.184 J] po2,∞ ambient oxygen partial pressure [atm, 1 atm = 1.013 × 105 Pa] R gas constant [ 1.98 cal mol-1 K-1] T temperature [K] t time [min] W weight loss of tobacco char up to time, t, or temperature, T [mg] Wc weight loss of tobacco char at completion of reaction [mg] Z pre-exponential factor [min-1 atm-m] a fraction of As decomposed at time, t, defined by a = W/Wc

Studies on the Natural Smouldering of Cigarettes: III. Determination of the Thermal Properties of Tobacco Shreds Packed in Columns

Abstract The values of effective thermal conductivity, specific heat and thermal diffusivity of various kinds of tobacco shreds, which are necessary for the solution of heat transfer problems of a smouldering cigarette, were determined. Effective thermal conductivity of tobacco shred packed into simulated cigarette columns was measured by a transient hot-wire method as a function of packing fraction at conditions of 20°C and 60 % relative humidity. Specific heat was measured with the aid of a differential scanning calorimeter (DSC). The thermal diffusivity was obtained from the values of effective thermal conductivity, specific heat and packing density. Effective thermal conductivity increased with increasing packing fraction (1 - e) and was uniformly expressed as a function of the total void fraction (et) inside the column regardless of tobacco types and stalk positions, whereas thermal diffusivity decreased with the packing fraction. At the same packing fraction, bright shreds produced higher values of effective thermal conductivity as well as higher specific heats (although specific heat was independent of the packing fraction) but had lower thermal diffusivity values than Burley and Matsukawa shreds.