Influence of facial hair length, coarseness, and areal density on seal leakage of a tight-fitting half-face respirator

Highly Efficient, Dual-Functional Self-Assembled Electrospun Nanofiber Filters for Simultaneous PM Removal and On-Site Eye-Readable Formaldehyde Sensing

Air pollution containing particulate matter (PM) and volatile organic compounds has caused magnificent burdens on individual health and global economy. Although advances in highly efficient or multifunctional nanofiber filters have been achieved, many existing filters can only deal with one type of air pollutant, such as capturing PM or absorbing and detecting toxic gas. Here, highly efficient, dual-functional, self-assembled electrospun nanofiber (SAEN) filters were developed for simultaneous PM removal and onsite eye-readable formaldehyde sensing fabricated on a commercial fabric mask. With the use of an electrolyte solution containing a formaldehyde-sensitive colorimetric agent as a collector during electrospinning, the one-step fabrication of the dual-functional SAEN filter on commercial masks, such as a fabric mask and a daily disposable mask, was achieved. The electrolyte solution also allowed the uniform deposition of electrospun nanofibers, thereby achieving the high efficiency of PM filtration with an increased quality factor up to twice that of commercial masks. The SAEN filter enabled onsite and eye-readable formaldehyde gas detection by changing its color from yellow to red under a 5 ppm concentrated formaldehyde gas atmosphere. The repetitive fabrication and detachment of the SAEN filter on a fabric mask minimized the waste of the mask while maintaining high filtration efficiency by replenishing the SAEN filters and reusing the fabric mask. Given the dual functionality of SAEN filters, this process could provide new insights into designing and developing high performance and dual-functional electrospun nanofiber filters for various applications, including individual protection and indoor purification applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s42765-023-00279-3.

Shaving Waivers in the United States Air Force and Their Impact on Promotions of Black/African-American Members

INTRODUCTION

Regulations of the United States Air Force (USAF) prohibit male members from growing beards. Shaving waivers can be issued to airmen who are not able to shave due to various medical conditions such as pseudofolliculitis barbae, a condition that predominantly affects Blacks/African-Americans. Beard growth has been anecdotally associated with a negative impact on career progression. This study sought to establish if shaving waivers are associated with delays in promotion and, if present, if this association leads to racial bias.

MATERIALS AND METHODS

An online survey that collected information relating to shaving waivers and demographic data was emailed to all air force male members at 12 randomly selected air force bases. Generalized linear models were conducted to test the waiver group difference in promotion time controlling for rank and the covariates of race/ethnicity, level of education, professional military education completion, and disciplinary action.

RESULTS

A total of 51,703 survey invitations were emailed to members, and 10,383 complete responses were received (20.08% response rate). The demographics of the study cohort closely matched that of the USAF. Shaving waivers were associated with a longer time to promotion (P = .0003). The interaction between race and waiver status was not significant, indicating that shaving waivers are associated with a similarly longer time to promotion in individuals of all races. However, 64.18% of those in the waiver group were Black/African-American despite only being 12.85% of the study cohort.

CONCLUSIONS

This study found an association between shaving waivers and delayed promotions. The majority of the waiver group was Black/African-American, which may lead to a racially discriminatory effect of the male grooming standards of the USAF.

The effect of mask fit test on the association between the concentration of metals in biological samples and the results of time-weighted average personal exposure: A study on Japanese male welders

OBJECTIVES

The mask fit test confirms whether the wearing condition of the wearer's face and the facepiece of the respirators are used appropriately. This study aimed to examine whether the results of the mask fit test affect the association between the concentration of metals related to welding fumes in biological samples and the results of time-weighted average (TWA) personal exposures.

METHODS

A total of 94 male welders were recruited. Blood and urine samples were obtained from all participants to measure the metal exposure levels. Using personal exposure measurements, the 8-h TWA (8 h-TWA) of respirable dust, TWA of respirable Mn, and 8-h TWA of respirable Mn were calculated. The mask fit test was performed using the quantitative method specified in the Japanese Industrial Standard T8150:2021.

RESULTS

Fifty-four participants (57%) passed the mask fit test. Only in the Fail group of the mask fit test, it was observed that blood Mn concentrations be positively associated with the results of TWA personal exposure after adjusting for multivariate factors (8-h TWA of respirable dust; coefficient, 0.066; standard error (SE), 0.028; P = 0.018, TWA of respirable Mn: coefficient, 0.048; SE, 0.020; P = 0.019, 8 h-TWA of respirable Mn: coefficient, 0.041; SE, 0.020; P = 0.041).

CONCLUSIONS

The results clarify that welders with high concentrations of welding fumes in their breathing air zone are exposed to dust and Mn if there is leaking air owing to the lack of fitness between respirators and the wearer's face when using human samples in Japan.

Respiratory protection preparedness in critical care healthcare workers: An observational audit of facial hair at a major tertiary hospital in Australia

BACKGROUND

Facial hair under a tight fitting P2/N95 respirator diminishes respiratory protection. There is limited guidance with respect to the threshold to be clean shaven in readiness to wear N95 respirators.

METHODS

We performed a cross sectional audit in late August 2021 to observe whether staff had facial hair that could decrease respiratory protection of tight fitting respirators. The audit was conducted in three critical care areas at a major tertiary public hospital in Australia during a period of moderate-to-high community prevalence of COVID-19. All staff observed had previously successfully completed quantitative fit testing with a clean shaven face in the preceding 12 months.

RESULTS

110 consecutive male critical care staff were observed including thirty staff who were required to wear a N95/P2 respirator at the time. Forty - five percent of male staff observed were not clean shaven in the face seal zone of their respirators.

CONCLUSIONS

The readiness to wear a tight-fitting respirator and hence the need to be clean shaven, should be guided by both state and local COVID-19 risk ratings, as well as the specific respiratory biohazard risks present in the clinical area at that time. During periods of significant community transmission of COVID-19, critical care clinical staff should be clean shaven, so they are fit-for-purpose and ready to wear a tight fitting respirator at short notice. Respiratory protection preparedness in critical care healthcare workers: An observational audit of facial hair at a major tertiary hospital in Australia.

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

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.

Facial Hair Decreases Fit Factor of Masks and Respirators in Healthcare Providers

In response to the current state of the COVID-19 pandemic, healthcare providers are using common surgical masks and filtering respirators in conjunction with the presence of facial hair, which could lead to a large number of particles passing into their respiratory system. The purpose of this study was to determine the fit factor effectiveness of filtering respirators and surgical masks in bearded versus non-bearded healthcare providers. A controlled randomized clinical trial (NCT04391010) was carried out, analyzing a sample of 63 healthcare providers. The fit factors of surgical masks and FFP3 filtering respirators for healthcare providers with (n = 32) and without (n = 31) facial hair were compared. Fit factors were measured during an exercises protocol in which healthcare providers wore surgical masks and FFP3 filtering respirators. Surgical mask fit factor comparisons did not show significant differences (p > 0.05) between healthcare providers with and without facial hair. In contrast, filtering respirator fit factor comparisons showed statistically significant differences (p < 0.01) between both groups, indicating that healthcare providers with facial hair showed lower fit factor scores, which implies a worse fit factor with respect to healthcare providers without facial hair. The fit factor effectiveness of filtering respirators was reduced in healthcare providers with facial hair. The authors of this paper encourage healthcare providers to trim their beards during filtering respirator use or wear full-mask filtering facepiece respirators, especially during the COVID-19 pandemic.

Quantitative fit testing of filtering face-piece respirators during the COVID-19 pandemic reveals anthropometric deficits in most respirators available in Iran

PURPOSE

Frontline health care workers (HCWs) must wear a standard N95 or FFP2 respirator during worldwide pandemics of respiratory diseases including COVID-19 to protect against airborne infectious pathogens when performing care activities. This study aimed to quantitatively investigate the fit of most of the common FFRs used during the COVID-19 pandemic in Iran.

METHODS

A total of 37 volunteers were fit tested in 20 selected FFRs in a randomized order. The selected FFRs were underwent quantitative fit testing by PortaCount® model 8038. To determine the effects of face sizes on respirator fit, the participants' facial dimensions were measured using a digital caliper.

RESULTS

The rate of passing fit tests for the studied FFRs were surprisingly low with 11 out of 20 FFRs having less than 10% passing fit tests and the best performers having only 43% and 27% passing fit tests (brands 2 and 20, respectively). Cup-shaped respirators provided significantly greater fit than the vertical flat-fold ones (p < 0.001). A significantly different FFs were found among the respirator brands (F = 13.60, p < 0.001).

CONCLUSION

Overall, unacceptably low fit factors were obtained from the studied FFRs. The main reasons for this are suspected to single size and style for each studied FFR. It confirms the importance and requirement of the proper respirator selection in that way fitted optimally into facial dimensions, appropriate usage, and properly performing the fit testing procedure. A unique fit test panel should be developed to guide respirator wearers in selecting the appropriate FFR for their specific face sizes.

Fit factor compliance of masks and FFP3 respirators in nurses: A case-control gender study

Aims

To determine the fit factor and compliance with American Industrial Hygiene Association (AIHA) and Occupational Safety and Health Administration (OSHA) requirements of surgical masks and filtering respirators in male versus female nurses.

Design

A case–control gender study performed from 2016 to 2019.

Methods

A gender and age matched‐paired sample of 74 nurses was recruited and divided into men (n = 37) and women (n = 37). FFP3 filtering respirators and surgical masks fit factors were compared between male and female nurses by Mann–Whitney U tests. These measurements were tested to pass or fail according to the OSHA (≥100) and AIHA (≥50) criteria by Fisher exact tests for a 95% confidence interval.

Results

Global fit factor mean (standard deviation) was 2.86 (2.73) and 3.55 (6.34) for male and female nurses wearing surgical masks (p = .180), respectively, and nobody passed neither OSHA nor AIHA criteria (p = 1.00). Nevertheless, global fit factor were 30.82 (28.42) and 49.65 (43.04) for male and female nurses wearing FFP3 respirators, respectively, being significantly lower and worse in male nurses (p = .037). According to OSHA criteria, only 2.70% and 13.51% of male and females nurses, respectively, passed with non‐significant difference (p = .199), meanwhile 21.62% and 48.64% of male and female nurses, respectively, passed AIHA criteria showing significant differences (p = .027) wearing FFP3 respirators.

Conclusions

All male and female nurses wearing surgical masks failed to pass OSHA and AIHA criteria. Global fit factor of the proposed FFP3 filtering respirators was decreased and worse in male than female nurses.

Impact

Our recommendation is to avoid surgical masks use for protective purposes and use the proposed FFP3 filtering respirators among nurses. Each nurse should be fit tested for its own respirator with special caution in male nurses due to their lower fit factor achieved and most of them failed to pass OSHA and AIHA criteria, especially during COVID‐19 pandemic.

Pseudofolliculitis Barbae in the U.S. Military, a Review

Introduction

Pseudofolliculitis barbae (PFB), also known as ingrown hairs commonly results from adherence to military grooming standards in those who have curly facial hair. Many patients respond to specific grooming techniques or topical medications but severe cases often warrant restrictions on shaving or laser therapy. The treatment of PFB is challenged not only by grooming standards but also evolving readiness requirements. More recently, the Navy discontinued permanent restrictions on shaving because of concerns for poor gas mask fitting. The goal of this review is to outline the history of PFB in the military, describe current policies, and offer a more uniform approach to treating PFB in the military. We also discuss challenges that surround the management of PFB in the Armed Forces.

Materials and Methods

We conducted a systematic review of the literature utilizing PubMed to identify both current and past management and discussion of PFB in both civilian and military settings. We also performed an internet search to identify pertinent military regulations and history of PFB within the Armed Forces. A query of TRICARE, the health care program for the U.S. Department of Defense Military Heath System, was also performed to assess civilian-referred laser treatment for Active Duty service members.

Results

PFB has a long history in the military dating back to World War I, when shaving was enforced not only to ensure good personal hygiene and to foster good order and discipline but also to ensure gas masks would seal in the event of a chemical attack. The management of PFB has presented a challenge in the military and even led to a social uproar in the 1970s. Policy changes in the military regarding shaving limitations, or profiles, have historically influenced how PFB is managed, but the basic tenets remain the same. Grooming techniques and topical medications can be effective in treating mild-to-moderate disease, but more severe cases of PFB respond best to laser therapy. Limitations on shaving remain an important part of management, especially during flares of the disease and while initiating therapy. Long-term shaving profiles may be needed for treatment-resistant cases. The impact of the Navy’s recent policy on PFB is also discussed.

Conclusions

Pseudofolliculitis Barbae is a prevalent skin disease in the Armed Forces. A better understanding of the disease and patients’ individual needs by the health care provider and commander is paramount.

Evaluation of the performance of replaceable particulate and powered air-purifying respirators considering non-recommended wearing methods

This study evaluated the performance of two respirators, a replaceable particulate respirator (RPR) and a powered air-purifying respirator (PAPR), worn according to non-recommended methods. Ten subjects wore either an RPR or PAPR according to the recommended method, or according to a non-recommended method, with a knit cover placed between the facepiece cushion and face, with a towel placed between the facepiece cushion and face, or with the headband on a helmet. The leakage rate of each wearing variation was then measured, according to the procedure for determining the protection factor of respiratory protective equipment, using atmospheric dust as required by JIS T8150. The average leakage rate for the RPR was 1.82-10.92%, whereas that of the PAPR was 0.18-0.42%. The performance of the RPR decreased when worn in methods outside of recommendations; however, there was no significant decrease in the performance of PAPR under any method of wear. Therefore, a PAPR is recommended for work in which a replaceable or disposable particulate respirator fails to provide sufficient protection against hazardous dust substances, or for workers who are unable to use a particulate respirator according to the recommended method owing to the work environment or health conditions.

'Occupational dermatoses from Personal Protective Equipment during the COVID-19 pandemic in the tropics - A Review'

The COVID-19 pandemic has enveloped the world and there has been a high incidence of occupational dermatoses related to Personal Protective Equipment (PPE) amongst healthcare workers (HCWs) during this period. Prevention and management of these conditions will not only improve staff morale and quality of life, but will also minimize the risk of breaching PPE protocol due to such symptoms. The tropical climate in Singapore predisposes HCWs to more skin damage and pruritus due to intense heat, high humidity and sun exposure. The effects of friction, occlusion, hyperhidrosis and overheating on the skin in the tropics should not be neglected. Preventive measures can be taken based on our recommendations, and the working environment can be made more conducive for frontline HCWs. We review the literature and discuss various preventive and management strategies for these occupational skin diseases for our frontline HCWs, especially those working in less controlled working environments beyond the hospital in Singapore. Shorter shifts and frequent breaks from PPE are recommended. Duration of continuous PPE-usage should not exceed 6 h, with breaks in non-contaminated areas every 2-3 h to hydrate and mitigate the risk of skin reactions. Other strategies, such as teledermatology, should be considered so that consultations can remain accessible, while ensuring the safety and well-being of our clinical staff.

Last-resort strategies during mask shortages: optimal design features of cloth masks and decontamination of disposable masks during the COVID-19 pandemic

Face masks and respirators are the most widely used intervention measures for respiratory protection. In the wake of COVID-19, in response to shortages and lack of availability of surgical masks and respirators, the use of cloth masks has become a research focus. Various fabrics have been promoted with little evidence-based foundation and without guidelines on design principles for optimal performance. In these circumstances, it is essential to understand the properties, key performance factors, filter mechanisms and evidence on cloth masks materials. The general community might also need to decontaminate and reuse disposable, single-use devices as a last resort. We present an overview of the filter materials, filter mechanisms and effectiveness, key performance factors, and hydrophobicity of the common disposable masks, as well as cloth masks. We also reviewed decontamination methods for disposable respiratory devices. As an alternative to surgical masks and respirators, we recommend a cloth mask made of at least three layers (300-350 threads per inch) and adding a nylon stocking layer over the mask for a better fit. Water-resistant fabrics (polyesters/nylon), blends of fabrics and water-absorbing fabrics (cotton) should be in the outside layer, middle layer/layers and inside layer, respectively. The information outlined here will help people to navigate their choices if facing shortages of appropriate respiratory protection during the COVID-19 pandemic.

Impact Protection Potential of Mammalian Hair: Testing the Pugilism Hypothesis for the Evolution of Human Facial Hair

Because facial hair is one of the most sexually dimorphic features of humans (Homo sapiens) and is often perceived as an indicator of masculinity and social dominance, human facial hair has been suggested to play a role in male contest competition. Some authors have proposed that the beard may function similar to the long hair of a lion’s mane, serving to protect vital areas like the throat and jaw from lethal attacks. This is consistent with the observation that the mandible, which is superficially covered by the beard, is one of the most commonly fractured facial bones in interpersonal violence. We hypothesized that beards protect the skin and bones of the face when human males fight by absorbing and dispersing the energy of a blunt impact. We tested this hypothesis by measuring impact force and energy absorbed by a fiber epoxy composite, which served as a bone analog, when it was covered with skin that had thick hair (referred to here as “furred”) versus skin with no hair (referred to here as “sheared” and “plucked”). We covered the epoxy composite with segments of skin dissected from domestic sheep (Ovis aries), and used a drop weight impact tester affixed with a load cell to collect force versus time data. Tissue samples were prepared in three conditions: furred (n = 20), plucked (n = 20), and sheared (n = 20). We found that fully furred samples were capable of absorbing more energy than plucked and sheared samples. For example, peak force was 16% greater and total energy absorbed was 37% greater in the furred compared to the plucked samples. These differences were due in part to a longer time frame of force delivery in the furred samples. These data support the hypothesis that human beards protect vulnerable regions of the facial skeleton from damaging strikes.

Do Various Respirator Models Fit the Workers in the Norwegian Smelting Industry?

Background

Respirator fit testing is a method to assess if the respirator provides an adequate face seal for the worker.

Methods

Workers from four Norwegian smelters were invited to participate in the study, and 701 respirator fit tests were performed on 127 workers. Fourteen respirator models were included: one FFABE1P3 and 11 FFP3 respirator models produced in one size and two silicone half masks with P3 filters available in three sizes. The workers performed a quantitative fit test according to Health and Safety Executive 282/28 with 5–6 different respirator models, and they rated the respirators based on comfort. Predictors of overall fit factors were explored.

Results

The pass rate for all fit tests was 62%, 56% for women, and 63% for men. The silicone respirators had the highest percentage of passed tests (92–100%). The pass rate for the FFP3 models varied from 19–89%, whereas the FFABE1P3 respirator had a pass rate of 36%. Five workers did not pass with any respirators, and 14 passed with all the respirators tested. Only 63% passed the test with the respirator they normally used. The mean comfort score on the scale from 1 to 5 was 3.2. The respirator model was the strongest predictor of the overall fit factor. The other predictors (age, sex, and comfort score) did not improve the fit of the model.

Conclusion

There were large differences in how well the different respirator models fitted the Norwegian smelter workers. The results can be useful when choosing which respirators to include in respirator fit testing programs in similar populations.

Effectiveness of commercial face masks to reduce personal PM exposure

Cycling and walking are promoted as means of transportation which can contribute to the reduction of traffic pollution in urban areas. However, cyclists and pedestrians may be exposed to high concentrations of air pollutants due to their proximity to vehicle emissions. Commercial face mask respirators are widely used, in both developing and developed countries, as an individual protective measure against particle pollution. However scientific data on the efficacy of face mask respirators in reducing airborne particle exposure is limited. In this study, a custom experimental set-up was developed in order to measure the effectiveness of nine different respirators under real environmental conditions in terms of particle mass concentration below 2.5 μm (PM_2.5), particle number concentration (PNC), Lung Deposited Surface Area (LDSA) and Black Carbon concentration (BC). Face mask performances were assessed in a typical traffic affected urban background environment in the city of Barcelona under three different simulated breathing rates to investigate the influence of flow rate. Results showed a median face mask effectiveness for PM_2.5 equal to 48% in a range of 14-96%, 19% in a range of 6%-61% for BC concentration, 19% in a range of 4%-63% for PNC and 22% in a range of 5%-65% for LDSA. For each pollutant under investigation, the best performance was found always with the same mask (N7) although it is not the most expensive (in a range of price of 1 to 44, its cost was 20 euros), which has a filter on the entire surface except for the 2 exhalation valves where air cannot enter but just exit and shows a good fit on the dummy head.