Accurate assessment of exposure using tracer gas measurements
Accurate assessment of exposure using tracer gas measurements
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DOI：
10.1016/j.buildenv.2018.01.017
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发表时间：
2018-03-01
影响因子：
7.4
通讯作者：
Melikov, Arsen
中科院分区：
文献类型：
--
作者：
Kierat, Wojciech;Bivolarova, Mariya;Melikov, Arsen
室内气流相互作用，特别是在呼吸区，对于评估室内空气污染的暴露是重要的。采用呼吸热人体模型模拟人体周围产生的对流边界层和呼吸气流。针对人体面部的局部气流被应用于增加气流相互作用的复杂性。在腋窝处释放CO2，在腹股沟处释放N2O，以模拟这两个身体部位各自产生的生物效率。用短响应时间和长响应时间的气体分析仪分别测量人体口/鼻处的示踪气体浓度。示踪气体浓度用平均值、标准差和第95百分位值表征。结果表明，测定这些参数所需的测量时间随着气体分析仪响应时间的减少而大幅减少，并且具有足够的精度。当仅存在CBL时，准确测量靠近呼吸区释放的示踪气体浓度所需的测量时间较短。对于更复杂的流动，由于CBL与呼出流的相互作用，所需的测量时间更长。结论是，准确的暴露评估要求仅在吸入期间进行浓度测量。因此，必须使用低响应时间和采样时间比吸入时间短得多的气体分析仪。
Room airflow interaction, particularly in the breathing zone, is important to assess exposure to indoor air pollution. A breathing thermal manikin was used to simulate a room occupant with the convective boundary layer (CBL) generated around the body and the respiratory flow. Local airflow against the face of the manikin was applied to increase the complexity of the airflow interaction. CO2 was released at the armpits and N2O at the groin to simulate the respective bio-effiuents generated at these two body sites. The tracer gas concentration at the mouth/nose of the manikin was measured with gas analyzers with short and long response times, respectively. The tracer gas concentration was characterized by the mean, standard deviation and 95th percentile values. The results revealed that the measurement time needed to determine, with sufficient accuracy, these parameters decreased substantially with a decrease in the response time of the gas analyzer. When only CBL was present, shorter measurement time was needed for the accurate concentration measurement of the tracer gas released close to the breathing zone. For more complex flow, as a result of CBL interaction with the exhalation flow, the needed measurement time was longer. It has been concluded that the accurate exposure assessment requires that the concentration measurements are performed only during the inhalation period. Therefore, gas analysers with low response time and sampling time that is considerably shorter than the inhalation period have to be used.