Thoracic Fraction of Inhaled Fiber Aerosol
Thoracic Fraction of Inhaled Fiber Aerosol
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DOI：
10.1080/15459624.2012.762608
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发表时间：
2013-04-01
影响因子：
2
通讯作者：
Su, Wei-Chung
中科院分区：
文献类型：
--
作者：
Cheng, Yung Sung;Su, Wei-Chung
尺寸选择性采样是一种与健康相关的方法，根据吸入颗粒物渗透到人体呼吸道不同区域的情况来收集空气中的颗粒物；因此，它是将健康风险与职业暴露相关联的最相关的抽样方法。当前对石棉和其他纤维进行取样的做法不是尺寸选择方法。胸部尺寸分数定义为可穿透喉部的吸入颗粒部分，已被认为是纤维气溶胶最相关的尺寸选择性采样方法。胸部分数基于人类用口呼吸的胸外气道中吸入的球形颗粒的 1-沉积，并针对颗粒可吸入性进行了校正。没有关于纤维气溶胶的可比信息；因此，没有技术依据来确定目前的胸部分数定义是否适用于纤维气溶胶。吸入纤维气溶胶的对照实验没有提供人体数据，原因很明显，大多数纤维材料在吸入时都具有潜在危险。我们的方法是测量纤维气溶胶在真实的人类口咽气道复制品中的渗透性，并将其与球形颗粒的数据进行比较。我们证明，真实的人体口腔气道复制品（包括口腔、咽部和喉部区域）在人体头部气道中提供了有用的球形和纤维颗粒沉积。这些数据可用于测试胸部分数曲线。球形穿透力与用于建立胸廓分数曲线的人体体内数据一致。对于相同的空气动力学直径，使用相同的复制品，两个人体口腔气道复制品的纤维穿过喉部的渗透率高于球形颗粒的纤维渗透率。因此，针对球形颗粒定义的胸部曲线可能不包括一些可以穿透到胸部区域的纤维。
Size-selective sampling is a health-related method to collect airborne particles based on penetration of inhaled particles into different regions of the human respiratory tract; thus, it is the most relevant sampling method to correlate health risks with occupational exposure. The current practice of sampling asbestos and other fibers is not a size-selective method. The thoracic size fraction, defined as the portion of inhaled particles that can penetrate through the larynx, has been suggested as the most relevant size-selective sampling method for fiber aerosol. The thoracic fraction is based on 1-deposition of inhaled spherical particles in the human extrathoracic airways for mouth breathing and corrected for the particle inhalability. There is no comparable information for fiber aerosols; therefore, there is no technical basis to ascertain whether the current thoracic fraction definition is suitable for fiber aerosols. No human data are available from controlled experiments of inhaled fiber aerosols for the obvious reason that most fiber materials are potentially hazardous when inhaled. Our approach was to measure penetration of fiber aerosol in realistic human oropharyngeal airway replicas and to compare that with data from spherical particles. We showed that realistic human oral airway replicas (including the oral cavity, pharynx, and larynx regions) provided useful spherical and fiber particle deposition in the human head airway. These data could be used to test the thoracic fraction curves. The spherical penetration is in agreement with human in vivo data used to establish the thoracic fraction curve. Fiber penetrations through the larynx of two human oral airway replicas were higher than those for spherical particles for the same aerodynamic diameter using the same replicas. The thoracic curve as defined for spherical particles, therefore, may not include some fibers that could penetrate to the thoracic region.