Effectiveness of N95 Masks against SARS-CoV-2: Performance Efficiency, Concerns, and Future Directions

Abstract

The coronavirus disease 2019 (COVID-19) epidemic, which is caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has continued to spread around the world since December 2019. Healthcare workers and other medical first responders in particular need personal protective equipment to protect their respiratory system from airborne particulates, in addition to liquid splashes to the face. N95 respirator have become a critical component for reducing SARS-CoV-2 transmission and controlling the scale of the COVID-19 pandemic. However, a major dispute concerning the protective performance of N95 respirators has erupted, with a myriad of healthcare workers affected despite wearing N95 masks. This article reviews the most recent updates about the performance of N95 respirators in protecting against the SARS-CoV-2 virus in the present pandemic situation. A brief overview of the manufacturing methods, air filtration mechanisms, stability, and reusability of the mask is provided. A detailed performance evaluation of the mask is studied from an engineering point of view. This Review also reports on a comparative study about the protective performance of all commercially available surgical and respiratory masks used to combat the spread of COVID-19. With the aim of protecting healthcare providers more efficiently, we suggest some potential directions for the development of this respiratory mask that improve the performance efficiency of the mask.

Effect of N95 Respirator on Oxygen and Carbon Dioxide Physiologic Response: A Systematic Review and Meta-Analysis

“…During the COVID-19 pandemic, respirators were increasingly used by healthcare workers to protect against infection. The N95 disposable filtration respirator was the most common filtering facepiece respirator, with a 95% filtration rate for particles less than 0.3 microns, which can protect against highly transmissible diseases such as tuberculosis, SARS, and COVID-19 [ 1 , 2 ]. N95 masks were not only used by healthcare workers, but were also used widely among the general population to protect from community infections in many situations, such as general work and outdoor exercise.…”

On‐Site Quantification and Infection Risk Assessment of Airborne SARS‐CoV‐2 Virus Via a Nanoplasmonic Bioaerosol Sensing System in Healthcare Settings

“…We assumed that a well‐fitted surgical mask (worn outside patient rooms by HCWs) could achieve a filtration activity 90% ( α = 0.9), while one FFP2 mask and an additional surgical mask on top (worn in the COVID‐19 patient‐rooms by HCWs) could achieve a filtration efficiency of 99% ( α = 0.99) (Table S4, Supporting Information). [ 19 ] It is worth noting that the efficiency ( α ) could vary significantly based on PPE conditions other than the type of mask, such as the face mask fit factor defined as a quantitative estimate of the fit of a particular respirator to a specific individual by the Occupational Safety and Health Administration (OSHA). [ 20 ] Thus, the individual exposure can be calculated by, $$$$\begin{equation} {D}_{\textit{RNA}}=\left(1-\alpha \right)\cdot \kappa \cdot \textit{IR}\underset{0}{\overset{T}{\int}}{C}_{\textit{RNA}}\left(t\right)\textit{dt} \end{equation}$$$$where κ is the fraction of viable viruses in the air, T represents the total exposure time and IR represents the inhalation rate (m 3 h −1 ).…”

A full-face mask for protection against respiratory infections

“…We also investigated the breathability of the device using the respiratory protection protocol [ 44 , 45 ]. The test consisted of four exercises: (1) the bending-over exercise, with which the subject shall bend at the waist, as if going to touch his/her toes for 50 s and inhale 2 times at the bottom; (2) the jogging-in-place exercise, with which the subject shall jog in place comfortably for 30 s; (3) the head side-to-side exercise, with which the subject shall stand in place, slowly turning his/her head from side to side for 30 s and inhale 2 times at each extreme; and (4) the head up-and-down exercise, with which the subject shall stand in place, slowly moving his/her head up and down for 39 s and inhale 2 times at each extreme.…”