Abstract View
Application of the NanoAerosol Generator in Efficacy Evaluation of Facial Coverings
SIQIN HE, Derek Oberreit, Steve Kosier, Kanomax FMT, Inc.
Abstract Number: 539
Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases
Abstract
The interest in filtration efficiency characterization tests of face masks and respirators has grown substantially in response to the worldwide spread of Covid-19 and the consequent demand increase of personal protective equipment (PPE) supplies. It is believed the particulate filtration efficiency of the filter material used for manufacturing PPEs primarily affects how effectively they can protect the user against health and safety risks from airborne particles. The characterization of filtration efficiency is therefore critically required to evaluate the protection level of a PPE product and guide the proper use of it. Despite the extra size classification step in their generation, monodisperse test particles are usually preferred for testing filters due to the fact that filtration efficiency is a parameter that is primarily size-dependent. Substantial information can get lost in the integral measurements of a polydisperse test, especially for the applications with a few sizes of interest in particular, e.g. the Covid-19 related studies. With smaller droplets (nominally 500 nm) than other aerosol generators, the Kanomax NanoAerosol Generator (NAG) 3250 can minimize the surfactant effect that makes it challenging to produce monodisperse aerosols from monodisperse particle standards.
In this work, the NAG 3250 was used as the particle generator to aerosolize 100 and 300 nm monodisperse polystyrene latex (PSL) particles in a filter testing rig designed based on the ASTM standards for surgical masks. These generated monodisperse PSL particles were subsequently used to evaluate the particulate filtration efficiency of more than 20 facial covering materials in comparison with a few commercial facial masks and respirators. The results were used to guide the selection of alternative facemasks.