Assessing the effect of beard hair lengths on face masks used as personal protective equipment during the COVID-19 pandemic

Abstract

Background Globally, a large percentage of men keep a beard at least occasionally. Workplace regulations prohibit beards with N95 respirators, but there is little information on the effect of beards with face masks worn by the public for protection against SARS-CoV-2. Methods and findings We examined the fitted filtration efficiency (FFE) of five commonly worn protective face masks as a function of beard length following the US Occupational Safety and Health Administration Quantitative Fit Test: N95 (respirator), KF94 and KN95, surgical/procedure, and cloth masks. A comparison using N95 respirators was carried out in shaven and bearded men. A detailed examination was conducted for beard lengths between 0 and 10 mm (0.5 mm increments). The effect of an exercise band covering the beard on FFE was also tested. Although N95 respirators showed considerable variability among bearded men, they had the highest FFE for beard lengths up to 10 mm. KF94 and KN95 masks lost up to 40% of their FFE. Procedure and cotton masks had poor performance even on bare skin (10–30% FFE) that did not change appreciably with beard length. Marked performance improvements were observed with an exercise band worn over the beard. Conclusions Though variable, N95 respirators offer the best respiratory protection for bearded men. While KF94 and KN95 FFE is compromised considerably by increasing beard length, they proved better options than procedure and cotton face masks. A simple exercise band improves FFE for face masks commonly used by bearded men during the COVID-19 pandemic.

Can 10x cheaper, lower-efficiency particulate air filters and box fans complement High-Efficiency Particulate Air (HEPA) purifiers to help control the COVID-19 pandemic?

“…A limited number of trials with small numbers of participants indicate high filtration using N95 respirators even with suboptimal fit or in the absence of fit testing and training. 65 66 67 68 69…”

Can disposable masks be worn more than once?

“…Fitted filtration efficiency (FFE) testing of aerosol particles was conducted as previously described ( Sickbert-Bennett et al, 2020 , Prince et al, 2021 ). Briefly, a custom-built stainless exposure chamber was used to conduct the U.S. Occupational Safety and Health Administration (OSHA) Quantitative Fit Testing Protocol.…”

“…Yet facemask usage remains a primary intervention to reduce personal exposure to pathogens during the COVID-19 pandemic, as well as to air quality emergencies such as wildfire smoke. Although reusable cloth masks have an advantage in sustainability of materials and easiness to clean, they tend to be more porous and looser fitting, and have been shown to provide poor performance compared to disposable facemasks and respirators that offer better fit and are constructed of materials with higher filtration efficiency ( Clapp et al, 2021 , Prince et al, 2021 , Sickbert-Bennett et al, 2021 ). Indeed, high performance disposable masks (e.g., N95 respirators, KN95 and KF94 masks) offer the best protection against SARS-CoV-2 infection ( Andrejko et al, 2022 ).…”

Resilience and Protection of Health Care and Research Laboratory Workers During the SARS-CoV-2 Pandemic: Analysis and Case Study From an Austrian High Security Laboratory

“…The constricted feeling from longterm wearing of FFP3 masks in combination with the reduced oxygen supply and dehydration due to sweating led to anxiety and circulatory problems for one team member. Furthermore, this PPE variant protection was considerably compromised by increasing beard length (Prince et al, 2021). As a consequence, we decided to use PPE variant 2 (Figure 1B) with a hood and PAPR, which allows for normal breathing, reduces heat stress, and prevents unintentional face and neck touching.…”