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首页> 外文学位 >The effect of ultrafine aerosol ( 0.5 to 50 nm (0.05 micrometers) ) on the deposition of radon progeny in human lungs and implications for the measurement of exposure.
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The effect of ultrafine aerosol ( 0.5 to 50 nm (0.05 micrometers) ) on the deposition of radon progeny in human lungs and implications for the measurement of exposure.

机译：超细气溶胶（0.5至50 nm（0.05微米））对ra子体在人肺中沉积的影响及其对暴露量的影响。

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摘要

Despite a generally acknowledged public health risk from indoor exposure to airborne radon progeny, measurement techniques in current use do not provide sufficient information to assess risk from exposures in the home. By contrast, a simple, direct, measurement (the working level month) is a reliable starting point for the evaluation of miners' risks from radon progeny exposure. Ultrafine particles (0.5 to 50 nm in diameter) are frequently present in room air, especially during high occupancy times when activities like cooking and cleaning are taking place; but they are virtually absent from mine air. Measurement techniques used to evaluate mine and indoor air exposures do not supply any size-based data. Few studies of ultrafine aerosol deposition in humans have been undertaken, and none of these has specifically examined ultrafine particle deposition in the radiosensitive bronchial region of the respiratory tract.;In this research, the effect of ultrafine aerosol on radon progeny deposition in the bronchial airways was studied using: (1) a unique human exposure data base involving 8 men and 4 women volunteers, (2) a mathematical model describing the attachment behavior of radon progeny in the presence of aerosol developed as part of this work, and (3) a human respiratory-tract deposition model.;The addition of ultrafine aerosol to the air breathed by human subjects more than doubled the amount of radon progeny activity deposited in the bronchial region of the subjects' lungs, although radon gas concentration was held constant during all exposure experiments. The gamma activity measured in vivo remained higher at all times after exposure to ultrafine aerosol, while the rate of gamma activity clearance from the region was, on average, about 40 percent faster following ultrafine aerosol exposure. The human exposure data demonstrated that some aerosol size information is crucial to the determination of regional lung deposition and, consequently, the calculation of dose. The level of aerosol size detail that is necessary in order to support the development of dosimetrically defined measurements was evaluated. Three critical ultrafine size ranges were defined using these techniques--0.5 to 4 nm, 4 to 30 nm, and 30 to 250 nm.
机译：尽管公认室内暴露于空气中的pro子代会带来公共健康风险，但当前使用的测量技术仍无法提供足够的信息来评估在家中暴露于ra气的风险。相比之下，简单，直接的测量（工作水平月份）是评估矿工暴露于don子代的风险的可靠起点。室内空气中经常存在超细颗粒（直径为0.5至50 nm），尤其是在进行烹饪和清洁之类的高占用时间期间；但实际上他们不在我的空中。用于评估地雷和室内空气暴露的测量技术无法提供任何基于大小的数据。很少进行人类超细气溶胶沉积的研究，这些都没有专门检查呼吸道放射敏感性支气管区域中超细颗粒的沉积。；在这项研究中，超细气溶胶对支气管中ra子体沉积的影响这项研究使用以下方法进行研究：（1）包括8名男性和4名女性志愿者的独特的人类暴露数据库；（2）描述了在这项工作中开发的在存在气溶胶的情况下ra子代的附着行为的数学模型；以及（3）人类呼吸道沉积模型；尽管在整个过程中ra气浓度保持恒定，但人类受试者呼吸到的空气中添加的超细气雾剂使沉积在受试者肺支气管区域中的ra子代活动量增加了一倍以上暴露实验。暴露于超细气溶胶后，体内测得的γ活性始终保持较高水平，而超细气溶胶暴露后，该区域的γ活性清除率平均快约40％。人体暴露数据表明，一些气溶胶大小信息对于确定局部肺部沉积以及因此确定剂量至关重要。评估了支持剂量确定的测量发展所必需的气溶胶尺寸细节水平。使用这些技术定义了三个关键的超细尺寸范围-0.5至4 nm，4至30 nm和30至250 nm。

著录项

  • 作者

    Schmalbeck, Linda Michaels.;

  • 作者单位

    The University of North Carolina at Chapel Hill.;

  • 授予单位 The University of North Carolina at Chapel Hill.;
  • 学科 Health Sciences Public Health.;Environmental Sciences.;Physics Radiation.
  • 学位 Ph.D.
  • 年度 1995
  • 页码 275 p.
  • 总页数 275
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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