American Association for Aerosol Research - Abstract Submission

AAAR 39th Annual Conference
October 18 - October 22, 2021

Virtual Conference

Abstract View


How You Test Matters: Respiratory Filtration Testing Using Common Aerosol Instruments

TIM JOHNSON, Greg M. Olson, Justin S. Koczak, Andrea J. Tiwari, TSI Incorporated

     Abstract Number: 217
     Working Group: Infectious Aerosols in the Age of COVID-19

Abstract
During the COVID-19 pandemic, the expertise of aerosol researchers has been called upon like never before. Many members of the aerosol science community have dedicated time and resources to testing face masks of various kinds in the interest of protecting medical personnel, other essential workers, and the general public. Numerous papers describing such results have been published by this community since the onset of the pandemic.

When testing filter efficiency, the first decision that must be made is whether the filter will be tested according to a standard method. If a standard method is not followed, decisions pertaining to instrumentation used in testing, face velocity, particle characteristics (size, neutralization, composition), and loading conditions must all be made. In the context of the pandemic, aerosol researchers made these decisions according to what was achievable with the resource they had available. Each of those decisions impact the filtration efficiency test results.

This presentation will illustrate the effects of those important decision on the measured efficiency of filters. This will be done using a dataset collected by testing a well-characterized control media, as well as a variety of barrier face covering materials (and combinations thereof). This testing used an experimental matrix that explores the influence of several variables (instrumentation type, face velocity, and particle size) on the final measurement of filtration efficiency. The effects of particle neutralization and loading will also be discussed.

Having illustrated the influence of each of those variables, this presentation will then review the literature to examine the range of choices made in recently published papers and infer the comparability of results among studies.