Effect of Flow Oscillation on the Loading Performance of Respirator Filter Media

PENG WANG, Da-Ren Chen, Virginia Commonwealth University

     Abstract Number: 413
     Working Group: Control and Mitigation Technology

Abstract
The particle loading on the filter media of respirators may occur due to the lasting usage of respirators, especially under the current COVID-19 pandemic and dusty working conditions, for examples, mining and civil construction. While a few studies on the effect of human’s breathing to the performance of clean respirator filter media have been reported, very limited research has been conducted to study the loading performance of respirators’ media under the human’s breathing condition. Despite respirator filter media, fibrous filter media used in various applications (i.e., HVAC filter panel, engine inlet filters) experience the oscillating flow conditions during most of their lifetime.

In this study, the instantaneous pressure drops and filtration efficiency of respirator filter media under the particle loading were investigated in the flow condition of both inhalation and exhalation. A flow simulator was utilized to generate the oscillating flow conditions. The filter media were challenged under different oscillating frequencies and compared with the case under the corresponding constant flow rate to investigate the effect of oscillating frequency on the performance of filter media. Both NaCl and Arizona dust (ARD) particles with different size distributions were utilized to study the size effect of particles on the loading performance of the filter media under the flow oscillation. In addition, the effect of exhalation moisture on the loading performance of the filter media was also investigated. The hygroscopicity of challenging particles was considered by utilizing both hydrophilic and hydrophobic particles. Our study shows the flow oscillation may significantly affect the loading performance of respirators’ filter media. Our study may provide some guidance to optimize the structure design of the filter media working under the ordinary flow oscillation.