監測人體呼吸道產生微粒之系統建置

Development of an Exhaled Breath Aerosol Monitoring System

顏稚浩(Chih-Hao Yen)

指導教授 ： 陳志傑

國立臺灣大學/公共衛生學院/職業醫學與工業衛生研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.01538

摘要

咳嗽和打噴嚏是產生生物氣膠的常見形式，同時也是傳播呼吸道疾病的重要途徑。但是咳嗽和打噴嚏是明顯的動作，可以提醒周遭的人注意疾病傳播的危險。但是近幾年來有研究指出在平靜呼吸下也有傳播生物氣膠的可能性，因此有系統的以實驗研究從一般呼吸產生氣膠的機制和特性是本項研究的內容。

人體呼出微粒監測系統包含數個部分，包括流量計、凝結核微粒計數器或是光學微粒計數器以及提供高流量乾淨空氣的空腔是本篇研究系統的主軸。受試者被招募來接受測試，實驗時受試者被要求要帶鼻夾，只能透過嘴巴對著連接乾淨空氣的空腔的管道呼吸，管道內的設備包含流量計監測受試者即時的呼吸流量，以及凝結核微粒計數器和氣膠光學分徑器同步監測受試者呼出的微粒特性。實驗過程中受試者必須遵照先前以呼吸模擬器建置出的標準呼吸曲線進行呼吸以確保不同受試者之間的可比較性。

測試所有的氣膠量測儀器，以白光氣膠分徑器型號 2000H以及凝結核微粒計數器型號 3025的反應時間最短，白光氣膠分徑器另外擁有量測呼出微粒粒徑分佈的功能，凝結核微粒計數器可以補足白光分徑器在小粒徑微粒無法量測的缺點。量測一位健康成年男性受試者的資料，發現人體在平靜呼吸下(較低的潮氣容積和呼吸頻率)產生微粒的濃度很低，但是隨著呼吸潮氣容積的增加，呼出微粒的濃度也隨之增加，但是呼出微粒的濃度會隨著呼吸頻率的增加而下降，推測這應該和微粒的慣性衝擊而在呼吸系統內再沉降造成數目損失有關。

關鍵字

呼出微粒 ； 微粒數目 ； 光學微粒計數器 ； 凝結核微粒計數器

並列摘要

Coughing and sneezing, as shown in previous studies, are important ways of generating aerosols, and therefore, common route to spread respiratory diseases. Both coughing and sneezing are audible and visible to alert people nearby. In this work, the mechanisms and characteristics of aerosol emission from “silent” breathing were experimentally investigated and validated.

An Exhaled Breath Aerosol Monitoring System, composed of a pneumotachograph, a condensation particle counter (or an optical counter with sizing capability) and an aerosol-free chamber with flow rate over 200 L/min, was the backbone of the experimental system set-up. The subject(s) were asked to respire through a mouth piece and the home-made pneumotachograph connected the aerosol-free chamber. In order to monitor the aerosol concentration during inhalation and exhalation , a condensation particle counter (and/or an aerosol size spectrometer) with sampling rate at least 10 Hz was connected to the T-shape adaptor between the mouth piece and the pneumotachograph. A nose clip was used to force the respiration through mouth only. Subjects were asked to perform a variety of breathing patterns generated by a cylinder-piston type breathing simulator, in order to study the breathing pattern dependency.

Among the aerosol instrument tested, Welas 2000H and TSI CPC 3025 had the shortest response time. The Welas has the advantage of providing sizing information of the exhaled breath aerosols. Condensation particle counter needs to be used when the aerosol size is smaller than the lower detection limit of Welas. From monitoring data of exhaled breath of a voluntary male subject, we found that under sedentary condition (low tidal volume, low breathing frequency), the aerosol concentration of the exhaled breath decreased from near room air down to zero after several breaths. Therefore, the subject was hooded with humidified (RH 70%) aerosol-free air to speed up the test process. The aerosol generation rate increased with increasing tidal volume but decrease with increasing frequency. For the same tidal volume, exhaled breath aerosol concentration decreased with increasing breathing frequency, indicating that portion of the exhaled breath aerosols were deposited due to inertial impaction.

並列關鍵字

Exhaled breath aerosol ； particle count ； optical particle counter ； condensation particle counter

參考文獻

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