公共衛生學系;Department of Public HealthKOUSAKA, YASUOYASUOKOUSAKAWANG, CHIU-SENCHIU-SENWANGOKUYAMA, KIKUOKIKUOOKUYAMA2008-07-302018-06-292008-07-302018-06-291982http://ntur.lib.ntu.edu.tw//handle/246246/80905Do particles in cigarette smoke grow larger in humid air? Results of our study indicate that condensation of water vapor on cigarette smoke particles takes place only under supersaturation conditions. Size distributions of smoke particles generated with filters (Wakaba brand, the Japan Tobacco and Salt Public Corporation) were measured by the apparatus shown in Fig.1. The experimental set-up consisted mainly of an ultramicroscopic sedimentation size analyser, a smoking device, two humidifiers and a psychrometer. Each humidifier consisted of a silica gel bed, a bubbler, and two control valves. The relative humidity of the air stream from each humidifier was controlled by adjusting the flow rates of the air streams through the bubbler and the silica gel bed. Supersaturation conditions can be obtained by heating the water in the bubblers. The apparatus was first tested by experiments with sodium chloride particles, generated by atomizing saline solutions and subsequently drying the droplets in a silica gel bed (not shown in Fig. 1 ). Figure 2 shows the measured geometric mean diameter ( number median diameter) of NaC1 particles as a function of relative humidity at 25℃. The results indicate that NaC1 particles have a deliquescent point at about 76﹪ relative humidity, which is in agreement with the value reported in the literature (see, for example, (2)). #B0182021en-US香菸微粒CIGARETTE SMOKE PARTICLESjournal article