Transport of aerosols and nanoparticles through respirators and masks

TL;DR

This study investigates how nanoparticles and viruses pass through surgical masks and N95 respirators, revealing similar filtering efficiencies and providing insights into their transport mechanisms, which inform pandemic and pollution policies.

Contribution

It offers novel experimental and analytical insights into nanoparticle transport and filtration in masks, combining in vitro, in vivo, and microscopy analyses.

Findings

Both mask types show similar efficiency in filtering nanoparticles.

Nanoparticle distribution varies across mask layers and on skin.

Analytical models elucidate pressure and flow within mask materials.

Abstract

In several countries wearing multiple surgical masks or N95 respirators was mandatory in public during the COVID pandemic. In this study, we investigated the transportation and filtering mechanism of heterogeneous nanoparticles and viruses through surgical masks and N95 respirators. We conducted experiments in vitro using aerosol spray paints containing nanoparticles and validated the findings in vivo on a human volunteer. Scanning electron microscopy was employed to analyse the transportation and distribution of nanoparticles in different mask layers and on pristine silicon substrates placed on human skin. We provide analytical insights into the pressure distribution and fluid velocity profiles within the complex polymer network. Remarkably, our results showed that both single surgical masks and N95 respirators demonstrated similar efficiency in filtering colloidal and jet-stream nanoparticles in the air. These comprehensive findings have significant implications for policymakers in defining regulations for airborne pandemics and air pollution control.