用於極端呼氣氣流與飛沫模擬之裝置的開發與應用

Abstract

許多的呼吸道傳播疾病(如流感、MERS、COVID-19等)具有高傳播力與造成重症的潛力，長期以來一直是公共衛生所關注的議題。在職業衛生的觀點中，源頭控制被視為最直接且有效率之方法，因此本研究團隊研發出一款名為BR-PEBAR(Breath-Responsive Personal Exhaled Breath Aerosol Receiver)的防疫設備，藉由即時過濾使用者的呼氣，以達成防止氣膠傳播與避免污染環境之目的。然而，該設備在開發時，僅於定流量條件下進行效能測試，因此，並無從得知其在咳嗽或噴嚏等情境之下之效能，也因此限制了其在實際應用層面的廣度。有鑑於此，本研究的目標在建立一套可調控氣流與微粒特性的系統，以模擬咳嗽過程中具代表性的動態氣流特徵，在配合微粒的產生後，除了可以用於測試防疫工具在咳嗽情境下的效能外，也可以做為公共衛生教育之輔助工具，協助學員對於氣膠傳播機制的理解，並建立有效的防護策略。

本研究乃為波以耳定律以及氣膠產生技術的結合應用。藉由調整儲氣罐的體積與壓力、氣體通道的阻抗、氣體觸發閥門的開啟速度以及其內部的構形等參數，成功重建文獻中的咳嗽氣流曲線，包括峰值流量、氣流持續時間、上升斜率與排出體積等。該模擬系統具備高度的操作彈性，可透過調整各別操作參數，組合出指定特徵的咳嗽氣流曲線(峰值流量誤差小於1 %)。而在微粒產生方面，透過可更換腔體與霧化溶液之設計，賦予了該系統可客製化的特性。測試結果顯示，若選用越大體積腔體與越濃的食鹽水溶液，可顯著增進可視化的效果。此外，在初步結合防疫產品的使用之後，也進一步確認了本模擬系統作為簡易教學或展示工具的可行性。未來可配合佳化參數設計與光源調整進一步強化視覺呈現效果。於測試防疫工具的效能層面，本研究以BR-PEBAR為例，進行防疫設備在咳嗽條件下捕捉呼氣微粒的效能驗證，結果顯示，在峰值流量為4.56 L/sec的咳嗽條件下，若僅佩戴BR-PEBAR且未啟動抽氣裝置(相當於無動力式裝置)時，對於次微米粒徑微粒捕集效率僅為11.4 %，若啟動內建抽氣風扇，則捕集效率可提升至87.3 %，若把咳嗽峰值流量降低至1.2 L/sec以下時，BR-PEBAR可達100 %的捕集效果。另外，測試結果也顯示，加裝24 ml的預存空間，可以使BR-PEBAR在峰值流量為2.4 L/sec時的捕集效率，由97.3 %增加至98.5 %，因此，未來除了著眼於風扇性能的提升外，亦可透過面體空間的優化設計，藉由創造更大的預存空間，進一步強化BR-PEBAR的整體效能。

綜合上述，本研究成功建構一套具可調整性與高再現性的咳嗽模擬系統，並展示了其具備研究、教學與實務應用等多面向的價值。

Many respiratory diseases (such as influenza, MERS, and COVID-19) are characterized by high transmissibility and the potential to cause severe illness, making them a persistent concern in public health. From the perspective of occupational hygiene, source control is considered the most direct and efficient strategy. In response, our research team developed a device called BR-PEBAR (Breath-Responsive Personal Exhaled Breath Aerosol Receiver), designed to filter users' exhaled breath in real time, thereby preventing aerosol transmission and reducing environmental contamination. However, this device was only tested under constant flow rate conditions during development, without considering scenarios involving short-duration, high-flow events such as coughing or sneezing—limiting its applicability in real-world settings. To address this gap, this study aimed to development a controllable system capable of simulating both airflow and particle characteristics representative of a cough event. Combined with particle generation, the system can be used not only to evaluate the performance of protective equipment under coughing conditions but also as an educational tool to assist learners in understanding aerosol transmission mechanisms and developing effective protective strategies.

This study integrates Boyle's law with aerosol generation techniques. By adjusting parameters such as tank volume and pressure, flow pathway resistance, valve actuation speed, and internal valve geometry, the system successfully reconstructed cough airflow profiles found in literature—including peak flow rate, duration, rise time, and exhaled volume. The system offers high operational flexibility, enabling the generation of cough airflow curves with target characteristics (with peak flow rate errors less than 1%). In terms of particle generation, the design allows interchangeable chambers and atomizing solutions, enabling system customization. Experimental results showed that using larger chambers and higher-concentration NaCl solutions significantly enhanced visualization. Furthermore, preliminary demonstrations with protective devices confirmed the system's feasibility as a simple teaching or presentation tool. Future improvements in parameter optimization and lighting configurations may further enhance its educational visual performance.

For protective equipment evaluation, this study used BR-PEBAR to validate its ability to capture exhaled particles under coughing conditions. Results showed that under a cough with a peak flow rate of 4.56 L/sec, BR-PEBAR captured only 11.4% of submicron particles without fan activation (passive mode), while activating the built-in fan increased the efficiency to 87.3%. When the cough peak flow was reduced to below 1.2 L/sec, the device achieved 100% capture efficiency. Additionally, adding a 24 ml reservoir space increased the capture efficiency from 97.3% to 98.5% at a peak flow rate of 2.4 L/sec, indicating that expanding the reservoir volume through facepiece design optimization can further enhance overall performance, alongside fan power improvements.

In summary, this study successfully established a highly adjustable and reproducible cough simulation system, demonstrating its multi-faceted value in research, education, and practical applications.