濾材與孔隙洩漏以及呼吸模式對簡易型防塵口罩整體防護效率的影響

The Effect of Filter and Faceseal Leakage on the Protection Performance of Disposable Masks

污染物會從口罩的濾材以及面部與口罩間的孔隙進入口罩中，再經由呼吸道進入人體。有別之前的研究只探討濾材的過濾效率，本研究著重在探討濾材與孔隙洩漏對簡易型防塵口罩整體防護效率的影響。本研究以新發展的個人防護具評估系統量測簡易型防塵口罩配戴在假人頭時以及真人時的洩漏率。在假人頭試驗中，受試口罩以矽膠密封在假人臉上或者在密封口罩與臉頰邊緣製造固定的洩漏率，分別觀察口罩濾材的洩漏率以及呼吸模式與呼吸頻率的影響。在真人實驗中，30位受試者進行口罩整體洩漏率的評估。口罩的孔隙洩漏率可由整體洩漏率減去濾材的洩漏率求得。結果發現以固定持續吸氣流量來量測口罩效率在高頻時會有高估的情形；在低頻時，會有低估的情形。因此，在從事口罩效率的評估時，呼吸頻率需納入考量。另外，微粒從孔隙的穿透率皆大於濾材穿透率，且手術用口罩所得之濾材穿透率與孔隙穿透率皆大於FFP系列的口罩。雖然FFP系列口罩對微粒的防護程度比手術用口罩好，但大部分會使口罩配戴者感覺不舒適，會在工作中移動口罩進而降低口罩的防護效率。因此，未來口罩的設計應朝向如何增加配戴者的舒適度與減少微粒從孔隙穿透的方向著手。

Contaminants enter inside the mask through the filter and faceseal leakage, and then enter the human body through the respiratory tract. Distinguished from previous studies only exploring the filter filtration efficiency, this study focuses on exploring the impact of filter and faceseal leakage on the overall protection efficiency provided by filtering facepiece respirators against dust. In this study, a newly developed personal sampling system was used to evaluate the leakage rate when a filtering facepiece respirator was donned either on a mannequin or a human subject. In the mannequin test, the test respirator was silicon-sealed on the face or with a fixed faceseal leak to investigate the filter leakage rate as well as the impact of the breathing pattern and frequency on the respirator protection. In the human test, 30 subjects were employed to assess the overall leakage rate. The faceseal leakage rate was obtained by the overall leakage rate minus the filter leakage rate. The results show the overall leakage rate was overestimated at a constant inhalation flow with high frequencies, otherwise, it was underestimated with low frequencies. Therefore, the breathing rate should be considered in the evaluation of respirator efficiency. In addition, the particle penetration through the faceseal leak was greater than that through the filter. The leakage rates of faceseal leaks and filter of surgical masks were greater than those of FFP series of respirators. Although the protection of FFP series of particulate masks is better than surgical masks, most wearers will feel uncomfortable, and move them during work, resulting in a decrease in protection. Therefore, the future mask design should be directed to how to increase the wearer’s comfort and reduce particulate penetration through the faceseal leaks.