Size distribution and sites of origin of droplets expelled from the human respiratory tract during expiratory activities
Size distribution and sites of origin of droplets expelled from the human respiratory tract during expiratory activities
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DOI：
10.1016/j.jaerosci.2008.11.002
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发表时间：
2009-03-01
影响因子：
4.5
通讯作者：
Katoshevski, D.
中科院分区：
文献类型：
--
作者：
Morawska, L.;Johnson, G. R.;Katoshevski, D.
本文采用一种新的呼气液滴研究系统（EDIS）对不同呼吸活动过程中产生的稀释校正液滴粒径分布进行了迄今为止最全面的研究。所有活动的大多数颗粒都是以一种或多种方式产生的，直径低于0.8 μ m，平均浓度高达0.75 cm（-3）。这些颗粒在所有呼吸活动（包括正常呼吸）期间以不同浓度出现。在所有的活动中都产生了1.8 μ m的第二种模式，但浓度较低，最高可达0.14 cm（-3）。这两种模式在持续发声期间变得最明显，分别产生0.04和0.16 cm（-3）的平均浓度，表明润滑声带的分泌物的雾化是液滴数量的主要来源。在呼气过程中产生的平均颗粒数浓度范围从呼吸的0.1cm（-3）到持续发声的1.1cm（-3）。对于0.5和20 μ m之间的颗粒，这意味着在0.8秒内蒸发到平衡液滴尺寸。(C)2008爱思唯尔有限公司保留所有权利。
A new expiratory droplet investigation system (EDIS) was used to conduct the most comprehensive program of study to date, of the dilution corrected droplet size distributions produced during different respiratory activities.Distinct physiological processes were responsible for specific size distribution modes. The majority of particles for all activities were produced in one or more modes, with diameters below 0.8 mu m at average concentrations up to 0.75 cm(-3). These particles occurred at varying concentrations, during all respiratory activities, including normal breathing. A second mode at 1.8 mu m was produced during all activities, but at lower concentrations of up to 0.14 cm(-3).Speech produced additional particles in modes near 3.5 and 5 mu m. These two modes became most pronounced during sustained vocalization, producing average concentrations of 0.04 and 0.16 cm(-3), respectively, suggesting that the aerosolization of secretions lubricating the vocal chords is a major source of droplets in terms of number.For the entire size range examined of 0.3-20 mu m, average particle number concentrations produced during exhalation ranged from 0.1 cm(-3) for breathing to 1.1 cm(-3) for sustained vocalization.Non-equilibrium droplet evaporation was not detectable for particles between 0.5 and 20 mu m, implying that evaporation to the equilibrium droplet size occurred within 0.8 s. (C) 2008 Elsevier Ltd. All rights reserved.