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KAGAMIYAMA I-CHOME, HIGASHI-HIROSHIMA 739, JAPAN (MS.; K.o.; s.o.) AND TOBACCO SCIENCE RESEARCH LABORATORY, JAPAN TOBACCO INC., 6-2, UMEGAOKA, AOBA-KU, YOKOHAMA 227, JAPAN (T.A.; M.M.; Y.1.)ABSTRACT. The change in concentration distribution of particulate contaminants emitted in a room was studied experimentally and theoretically to investigate whether the transport of contaminants in a room with a source of particles can be predicted by numerical simulation. Tracer contaminants, monodisperse latex particles, were introduced into a 3.3 m X2.7 m X 2 m room with clean air for a given time, and the change in the contaminant concentrations with time was measured at various positions in the room. Calculations of the spatial and temporal distributions in the gas velocity and contaminant concentration were performed to predict the concentration change, with the Navier-Stokes and convection-diffusion equations solved numerically. The experimental results showed that the concentration distribution depends on the position of introduction of the contaminants. It was also indicated that the contaminants introduced near the room floor diffuse more than predicted. However, the calculated concentrations agreed almost quantitatively with the measured results, except near the floor and walls. The change in the concentration with time and the dependence of the concentration distribution on the position of the particle source were well reproduced by the calculation. AEROSOL SCIENCE AND TECHNOLOGY 25:242-255 (1996)

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The effect of water vapour on the growth of cigarette smoke particles was investigated by a light-scattering method which can measure the particle size distribution and the refractive index. The particle growth, below 90 % relative humidity, was less than 10 % for both main and side-stream smoke. The results were discussed with equations derived from the weight changes of smoke condensate in moist air, and with the changes of the refractive index. Calculations showed that the cigarette smoke particle reaches equilibrium very quickly and that it doubles its radius at about 99.5 % relative humidity.

The objectives of this research were to improve and standardize a relatively easy, highly sensitive and highly accurate method of measuring nicotine, cotinine and trans-3'-hydroxycotinine in the urine of non-smokers exposed to environmental tobacco smoke (ETS) and to clarify the reliability of this method. Blinded studies using this analytical method were conducted in two universities. Standard solutions of nicotine, cotinine and trans-3'-hydroxycotinine were prepared at one university, divided in two parts and sent to another two universities for analyses by gas chromatography-mass spectrometry (GC/MS) without revealing the concentrations. It was found that the assay lower limit was at a level that could be used in passive smoking surveys and good results were obtained in crosschecks of samples of unknown concentration between the two universities. Since this method was considered to be useful for analyzing these urinary substances, ETS exposure experiments were performed in three universities using urinary nicotine, cotinine and trans-3'-hydroxycotinine as specific biomarkers of the urine. Non-smokers were exposed to ETS in an exposure room in each university. It was found that the nicotine concentrations in the urine of the subjects exposed to ETS reached a peak at about 2 hours after the end of exposure, which was somewhat later than that in active smokers. Because cotinine and trans-3'-hydroxycotinine in the urine are metabolites of nicotine, it was evident that the quantities were lower and the increasing rates were also less than that of nicotine. When the deceases in nicotine/ creatinine, cotinine/creatinine and trans-3'-hydroxycotinine/creatinine ratios in the urine were calculated using theoretical curves, the half-life times were calculated to be 13.9, 20.0 and 63.0 hours, respectively.