Respiratory Protective Devices Research Articles

Prevalence of chronic respiratory symptoms and associated factors among woodwork workers in Bahir Dar City, Ethiopia; a comparative cross-sectional study

BackgroundExposure to wood dust can cause respiratory symptoms, like cough, phlegm, breathlessness, and chest pain, reduce lung function.ObjectiveThe objective of the study was to assess the prevalence of respiratory symptoms and associated factors among woodwork workers in Bahir-Dar city, Ethiopia.MethodsA comparative cross-sectional study was employed among 229 exposed and 228 unexposed groups. Participants for the study were selected using simple random sampling technique. The chronic respiratory symptoms were assessed using a questionnaire adopted from the American Thoracic Society. The data was entered using Epi-Data version 4.6 and export to SPSS version 22 for analysis. Poisson regression, Multivariate linear regression and multivariable logistic regression analysis were used to identify factors associated with woodworkers, general population and in pooled analysis.ResultThe prevalence of having at least one chronic respiratory symptom was higher among exposed group (59.4%) than unexposed group (18.0%) with PR = 3.03(95%CI: 2.45, 4.45). In woodworker; Not taking health and safety training(5.15,95%(CI:1.93–13.76),primary educational(3.85,95%,CI:(1.1,13.47), not using Mask(6.38, 95%CI:(2.69–15.76) & number of families(3.05,95%,CI:1.04–9.028), In general population; Number of family members(2.75, 95%CI:1.1–7.19)& lower monthly income (3.3, 95%CI: (1.49–7.4), and In pooled analysis; wood dust exposure status 14.36 95%, CI:(7.6–27.00),primary education(2.93,95%CI:1.24–6.92), number of families(3.46,95%CI:1.8–6.64), lower monthly income(2.13,95%CI:1.19–3.81), & smoking (6.65, 95%CI:1.19–36.9) were associated with respiratory symptom.ConclusionPrevalence of respiratory symptoms was higher among exposed group than unexposed group. Reduced wood dust exposure status, Provision of occupational safety and health training, use of respiratory protective devices is recommended to reduce respiratory symptoms among woodwork workers.

Re-inventing protection in a post-pandemic world: A new aerodynamic endonasal filtration technology

Is there a “missing device” for respiratory personal protection? Does it exist an easy-to-use device, allowing extensive use in everyday settings by the population, maximizing tolerability and low visual and physical invasiveness protecting from a wide range of threats including airborne pathogens, hence including the particle range of fine and ultrafine particles? Looking at the recent past, in the urgency of finding ready-to-use solutions for the respiratory protection of the population during the outbreak of the SARS-CoV-2 pandemic, devices for occupational safety have been used, such as filtering face masks. These are devices intended for workers operating during work shifts in environments characterized by potential high risk, known a priori, often directly sensible; this makes wearers motivated to tolerate discomfort for a given period to face a localized risk, and safety managers determined to supervise compliance with usage specifications. Their use by general population has implied known shortcomings, such as weak compatibility with relational work and activities, low tolerability during prolonged use, low compliance with the proper use of the device, all of this lessening actual protection. The need for a new perspective has emerged, targeting effectiveness in whole daily life, rather than punctual efficacy. Nasal filters are promising candidates to protect individuals throughout the day during the most varied activities, but they lack a systematic definition as a device and as a product; it follows that the high complexity needed to reach an effective performance envelop is generally underestimated. By reviewing available literature, the present paper draws on the experience from the pandemic and infers systematic product specifications and characterization methods for a new, effective personal respiratory protection device; these specifications are compared with the stringent constraints associated with the endonasal applications and, based on air filtration state of the art, quantifies the need for technology disruption and outlining possible new development paths.

Validation of krypton as a new tracer gas for the standardization tests of collective and individual protection systems.

Sulfur hexafluoride (SF6) is the reference tracer gas in many international standards for characterizing respiratory protective devices (RPD), fume cupboards, building ventilations, and other installations. However, due to its significant impact on global warming, its use is becoming increasingly restrictive. Krypton 84 (Kr) was chosen to be a possible replacement based on theoretical and practical criteria for the properties that a substitute gas should possess. While compliance with these criteria is generally sufficient to guarantee the reliability of the choice, it is essential in the case of widespread use such as a standard to validate experimentally that this tracer has the same behavior as SF6. In this regard, numerous tests have been carried out to characterize the face leakage of RPD and the rupture of containment of fume cupboards performance tests under different operating conditions. The results obtained are identical with both tracers and lead us to propose the use of Kr as a new reference gas in standards for which SF6 was used.

Effective removal of odors from air with polymer nonwoven structures doped by porous materials to use in respiratory protective devices

Effective removal of odors from air with polymer nonwoven structures doped by porous materials to use in respiratory protective devices

A systematic review of passing fit testing of the masks and respirators used during the COVID-19 pandemic: Part 1-quantitative fit test procedures.

During respiratory infection pandemics, masks and respirators are highly sought after, especially for frontline healthcare workers and patients carrying respiratory viruses. The objective of this study was to systematically review fit test pass rates and identify factors influencing the fitting characteristics. Potentially relevant studies were identified using PubMed, Scopus, Web of Science, and Science Direct during the COVID-19 pandemic from February 5, 2020, to March 21, 2023. The search strategy using the following keywords was conducted: Quantitative Fit Test, Condensation Nuclei Counter, Controlled Negative Pressure, PortaCount, Sibata, Accufit, Fit, Seal, Mask, Respirator, Respiratory Protective Device, Respiratory Protective Equipment, Protective Device, Personal Protective Equipment, COVID-19, Coronavirus, and SARS-CoV-2. The quality of the included studies was also assessed using the Newcastle-Ottawa scale. A total of 137 articles met the eligibility criteria. Fifty articles had a quality score of less than 7 (good quality). A total of 21 studies had a fit test pass rate of less than 50%. 26 studies on disposable respirators and 11 studies on reusable respirators had an FF of less than 50 and less than 200, respectively. The most influential factors include respirator brand/model, style, gender, ethnicity, facial dimensions, facial hair, age, reuse, extensive movement, seal check, comfort and usability assessment, and training. 37.36% of the disposable respirator studies and 43% of the reusable respirator studies did not report fit test results. 67.86% of the disposable respirator studies had a fit test pass rate greater than 50%, and 35.84% of these studies had an FF greater than 100. Also, 85.71% of the reusable respirator studies had a fit test pass rate greater than 50%, and 52.77% of these studies had an FF greater than 1000. Overall, the fit test pass rate was relatively acceptable. Newly developed or modified respirators must undergo reliable testing to ensure the protection of HCWs. Subject and respirator characteristics should be considered when implementing fit testing protocols. An optimal fit test panel should be developed prior to respirator design, certification, procurement decisions, and selection procedures.

Effects of Cement Dusts on Peak Expiratory Flow Rate (PEFR) in Female Cement Dust Exposed Construction Workers

Background: Occupational and environmental lung diseases are the major problems of clinical medicine. The cement dust workers are constantly exposed to high amounts of visible ambient air particulate matter, mostly without any respiratory protective device. Therefore, the inhalation of dust over periods of time leads to impaired lung functions. Objectives: To observe the effects of cement dust exposure on PEFR in female cement dust workers. Methods: This cross-sectional study was conducted in the Department of Physiology, Rangpur Medical College, Rangpur from July 2016 to June 2017. A total of 60 female subjects aged 20–50 years were selected for the study. Among them, 30 were apparently healthy workers exposed to cement dust, and 30 apparently healthy height, weight & BMI-matched subjects not exposed to cement dust were selected as control from the surrounding community. Their pulmonary functions were studied by measuring PEFR. For statistical analysis, an unpaired ‘t’-test was performed by computer-based software SPSS-17.0 version for Windows. Results: The mean measured and mean percentage of the predicted value of PEFR was significantly (p_0.001) lower in cement dust-exposed female workers (CD- EFW) than the non-exposed female workers (CD-NEFW). Conclusion: From the result of this study, it can be concluded that cement dust (CD) may have harmful effects on some pulmonary functions. J Rang Med Col. September 2023; Vol. 8, No. 2: 25-28

Chronic Respiratory Symptoms and Associated Factors among Fruit and Vegetable Workers in Addis Ababa, Ethiopia: A Comparative Cross sectional Study

BackgroundFruit and vegetable market is an abundant source of bioaerosols. Exposure to organic and inorganic waste and long-term inhalation of bioaerosols during working hours leads to chronic respiratory symptoms. Hence, this study aimed to determine the prevalence of chronic respiratory symptoms and related factors among fruit and vegetable workers compared with the control group in Addis Ababa, Ethiopia. Methods and materialsA comparative cross-sectional study was conducted from 2020 to 2021. Data were entered in EpiData 3.1 and exported to Statistical Package for the Social Sciences (SPSS) version 25. Logistic regressions were computed to depict the data and related factors. The culture method was done to count and compare bacterial and fungal concentrations between fruit and vegetable workers and office workers. ResultsIn this study, the prevalence of chronic respiratory symptoms (PR = 2.87, 95% confidence interval [CI]: 1.772–4.66) was significantly higher among fruit and vegetable workers (46.7%) than controls (23.4%). Sex (adjusted odds ratio [AOR] = 2.11, 95% CI = 1.12–3.98), educational status (AOR = 1.34, 95% CI = 0.78–2.32), working hours per day (AOR = 3.91, 95% CI = 1.586–9.65), and working department (AOR = 3.20, 95% CI = 0.90–11.40) were associated with chronic respiratory symptoms. Bacterial and fungal concentrations were significantly higher in the air of the vegetable market (276 colony-forming unit) than the air in the workplace of controls (7 colony-forming unit). ConclusionThe fruit and vegetable market workers (greengrocers) had a higher prevalence of chronic respiratory symptoms relative to office workers. Respiratory protective devices should be given to deliver preventive measures.

Bagasse dust exposure and chronic respiratory symptoms among workers in the Metehara and Wonji sugar factories in Ethiopia: a longitudinal study design

BackgroundEthiopia’s sugar factories are growing by creating job opportunities for thousands of workers with varying educational, professional and socioeconomic backgrounds. These sugar factories are a source of several hazards that...

Respiratory Protection: Lessons Learned from a Global Pandemic.

The COVID-19 pandemic exposed the limitations of global health systems' abilities to manage the rapid spread of a novel infectious disease, which was exacerbated by shortages of respiratory protective devices and other critical personal protective equipment (PPE). An advisory panel of experienced health-care professionals with backgrounds in Occupational and Environmental Health and Safety (OEHS), Infection Prevention, Nursing, and Clinical Application Specialists convened to discuss challenges and strategies associated with the selection and use of respiratory protective devices as experienced during the first year of the COVID-19 pandemic. This discussion led to the following recommendations: 1) the need for clear communication of alternative respiratory protection selection and use recommendations in accordance with US regulatory and agency guidance; 2) the need for collaboration between Infection Prevention, OEHS, clinical staff, supply chain/materials management, emergency preparedness, executive leadership, and finance; 3) the need for adequate stockpiling, inventory rotation, and diverse respiratory protection options to accommodate the majority of health-care workers; 4) the need for efficient and innovative strategies to communicate evolving regulatory, agency, and facility recommendations and to deliver appropriate training on respiratory protection; and 5) the need for additional research on respiratory protection use - involving filtering facepiece respirators (FFRs) as well as other respirator types designed to be reused - to balance infection prevention best practices with a sustainable process. In conclusion, these considerations may offer guidance and identify areas for research on preparedness, communication, education, and training to enhance the preparation of health-care facilities including community-based health-care organizations for unexpected public health events.

Oregon Project Firstline: A needs assessment of healthcare personnel infection prevention knowledge and training preferences

Background: Infection prevention and control (IPC) competency is critical for healthcare personnel (HCP) and patient safety. In collaboration with the CDC new national IPC training collaborative called Project Firstline, the Oregon Health Authority’s (OHA) Healthcare Associated Infection (HAI) Program established a state-level program in 2021. The goal of Oregon Project Firstline is to provide relevant, accessible, and engaging IPC training materials for our state’s HCP. We assessed the IPC learning needs of Oregon’s healthcare workforce, and to understand the preferred methods and formats of training across the various HCP roles. Methods: OHA’s HAI program recruited HCP by distributing electronic surveys through multiple healthcare, regulatory, and public health partners’ email listservs and HCP-targeted newsletters. Survey responses were recorded from September 23 to December 10, 2021. The HAI program assessed respondents’ IPC knowledge, online and in-person job training preferences, frequently used training devices, and trusted sources for IPC information. An individual’s understanding of an IPC topic was categorized based on their self-assessed confidence in their knowledge and ability to teach the topic to others. In total, 6,382 surveyed responses were analyzed. Results: The average understanding among HCP was lowest in IPC topics relating to triage and isolation of contagious patients and fit testing of respiratory protection devices. For these topics, 3,208 HCP (66.21%) and 3,657 HCP (75.48%) HCP, respectively, did not understand the topic well enough to teach others (Fig. 1). The highest number of HCP (n = 2,512, 39.36%) requested additional training in methods on how to educate others about IPC topics (ie, “train the trainer”). Surveyed respondents most frequently used personal computers for job trainings in both work and at-home settings (n = 4,603, 72.12%) and 3,437 HCP (53.85%) were open to either in-person or remote formats for job education. The CDC and OHA were the most frequented and trusted IPC sources among surveyed HCP: 4,124 HCP (64.62%) and 3,584 HCP (56.16%), respectively. Conclusions: IPC is a critical topic in HCP training across all healthcare facility types and employee roles. Effective educational planning includes understanding the learners’ knowledge needs and preferred methods of learning. Our learning needs assessment identified important IPC knowledge gaps and will help ensure that our training courses will be offered in effective educational formats for Oregon’s diverse HCP. Future training will include appropriate triage of potentially infectious patients, respiratory fit testing, and general IPC “train the trainer” sessions. Additionally, we will offer both in-person and remote options.Disclosures: None

Respiratory protective device: One size to fit them all?

When exposed to hazardous or toxic substances, workers may be required to wear respiratory protective devices, selected in accordance with the pollutant, required protection level, individual characteristics, and work conditions. To emphasize the importance of the selection procedure, this study aimed to investigate the effects of the facial dimensions and breathing rate on the fit and the protection efficiency provided by full-face respirators. Manikin total efficiency measurements (mTEs) were then conducted on five head forms of various facial dimensions equipped with nine respirators of different models and sizes. A breathing machine simulating sinusoidal breathing rates was used to represent seven work rates, from rest to maximal intensity. For each experiment, the manikin fit factor (mFF), characterizing the respirator fit on the head form, was measured by a controlled negative pressure method. By varying the head form, respirator, breathing rate, and mFF, a total of 485 values of mTE were measured. Findings indicate that even if the respirator was equipped with a high-efficiency filter, mTE strongly decreases if the respirator does not fit the face of the wearer. In particular, it was highlighted that one given respirator cannot fit all facial dimensions and that the best match between the respirator size and facial dimensions is difficult to predict because respirator sizes are not standardized. Moreover, although the total efficiency of a well-fitted respirator naturally decreases when increasing the breathing rate due to filtration mechanisms, the reduction is more significant if the respirator does not fit well. To consider both the mTE and the breathing resistance, a quality factor value was determined for each tested combination of head form, respirator, and breathing rate. The maximum manikin fit factor mFFmax measured for each combination of head form and respirator was compared to that measured on nine human subjects with similar facial dimensions, providing encouraging results concerning the use of head forms during respirator testing.

Determining the filtration effectiveness of non-standard respiratory protective devices by an ad-hoc laboratory methodology

The recent pandemic caused by COVID-19 profoundly changed people's habits. Wearing a face mask has become usual in everyday life to reduce the risk of infection from airborne diseases. At the beginning of the pandemic, the massive request of surgical or filtering face piece (FFP) masks resulted in a global shortage of these devices for the most exposed people, such as healthcare workers. Due to this high demand for respiratory protective devices, many industrial plants have partly converted to the production of face masks using adapted materials and not complying with any specific regulation (non-standard respiratory protective devices or community masks). In this work, an ad-hoc laboratory methodology has been developed to evaluate the filtration efficiency of the materials that compose the community masks using specific instrumentation. The instrumentation consists of three main tools: an aerosol generator, a specifically designed measuring chamber, and an optical particle sizer (OPS) for the measurement of aerosol concentration. The generated aerosol was sent into the measuring chamber, divided into two separate sections by the respiratory mask. The OPS measured the aerosol mass concentration upstream and downstream of the respiratory mask, and from the concentration difference the filtration efficiency was evaluated. The proposed methodology has been validated by evaluating the particle filtration efficiency (PFE) of certified respiratory masks and was then applied for the evaluation of the filtration efficiency of different types of non-standard or community masks to analyze their effectiveness in protecting from the risk of infection of airborne diseases.

Face mask performance related to potentially infectious aerosol particles, breathing mode and facial leakage.

During the COVID 19 pandemic, wearing certified Respiratory Protective Devices (RPDs) provided important means of protection against direct and indirect infections caused by virus-laden aerosols. Assessing the RPD performance associated with infection prevention in standardised certification tests, however, faces drawbacks, such as the representativeness of the test aerosols used, the protection of third parties during exhalation or the effect of facial leaks. To address these drawbacks, we designed a novel test bench to measure RPD performance, namely the number based total efficiency, size-segregated fractional filtration efficiency and net pressure loss, for 11 types of certified surgical masks and Filtering Face Pieces dependent on breathing mode and facial fit. To be representative for the context of potentially infectious particles, we use a test aerosol based on artificial saliva that is in its size distribution similar to exhaled aerosols. In inhalation mode excluding facial leaks, all investigated samples deposit by count more than 85% of artificial saliva particles, which suggests a high efficiency of certified RPD filter media related to these particles. In exhalation mode most RPDs tend to have similar efficiencies but lower pressure losses. This deviation tends to be significant primarily for the RPDs with thin filter layers like surgical masks or Filtering Face Pieces containing nanofibers and may depend on the RPDs shape. Both the filtration efficiency and pressure loss are strongly inter-dependent and significantly lower when RPDs are naturally fitted including facial leaks, leading to a wide efficiency range of approximately 30-85%. The results indicate a much greater influence of the facial fit than the filter material itself. Furthermore, RPDs tend be more effective in self-protection than in third-party protection, which is inversely correlated to pressure loss. Comparing different types of RPDs, the pressure loss partially differs at similar filtration efficiencies, which points out the influence of the material and the filter area on pressure loss.

An Overview on Exploitation of Graphene-Based Membranes: From Water Treatment to Medical Industry, Including Recent Fighting against COVID-19.

Graphene and its derivatives have lately been the subject of increased attention for different environmental applications of membrane technology such as water treatment and air filtration, exploiting their antimicrobial and antiviral activity. They are interesting candidates as membrane materials for their outstanding mechanical and chemical stability and for their thin two-dimensional (2D) nanostructure with potential pore engineering for advanced separation. All these applications have evolved and diversified from discovery to today, and now graphene and graphene derivatives also offer fascinating opportunities for the fight against infective diseases such as COVID-19 thanks to their antimicrobial and antiviral properties. This paper presents an overview of graphene-based 2D materials, their preparation and use as membrane material for applications in water treatment and in respiratory protection devices.

Microbial Contamination in the Coffee Industry: An Occupational Menace besides a Food Safety Concern?

Respiratory abnormalities among workers at coffee roasting and packaging facilities have already been reported; however, little is known about microbiological contamination inside coffee production facilities. This study intends to assess the microbial contamination (fungi and bacteria) in two coffee industries from Brazil with a multi-approach protocol for sampling and for subsequent analyses using four main sources of samples: filtering respiratory protection devices (FRPD) used by workers, settled dust, electrostatic dust cloths (EDC) and coffee beans. The fungal contamination in the assessed industries was also characterized through the molecular detection of toxigenic species and antifungal resistance. Total bacteria contamination presented the highest values in FRPD collected from both industries (7.45 × 104 CFU·m−2; 1.09 × 104 CFU·m−2). Aspergillus genera was widespread in all the environmental samples collected and sections with clinical relevance (Fumigati) and with toxigenic potential (Nigri and Circumdati) were recovered from FRPD. Circumdati section was observed in 4 mg/mL itraconazole. Sections Circumdati (EDC, coffee beans and settled dust) and Nidulantes (EDC, coffee beans and FRPD) were detected by qPCR. Some of the targeted Aspergillus sections that have been identified microscopically were not detected by qPCR and vice-versa. Overall, this study revealed that microbial contamination is a potential occupational risk in the milling stage and should be tackled when assessing exposure and performing risk assessment. In addition, a multi-sampling campaign should be the approach to follow when assessing microbial contamination and FRPD should be included in this campaign. Occupational exposure to mycotoxins should be considered due to high fungal diversity and contamination. A One Health approach should address these issues in order to prevent consumption of coffee crops and beans infected by fungi and, more specifically, to avoid widespread azole resistance.

Pneumoconiosis prevention and personal protective equipment

Inhalation of mineral dust increases the risk of pneumoconiosis which is an incurable and irreversible occupational disease. If the concentration of fibrogenic dust significantly exceeds the occupational exposure limit (OEL), the risk of pneumoconiosis becomes unacceptably high. The disease prevention involves the use of the collective prevention equipment and medical control. If these measures are insufficient, the respiratory protective devices are used. But respirators lack reliability. For example, pneumoconiosis (the initial stages of the disease) was found in a miner who had worked in the mine for only about six months. The miners cannot use respirators for a long time: they complicate communication during work and excessively impair gas exchange when breathing. The average concentration of carbon dioxide in the air inhaled from a respirator mask may exceed the maximal allowable concentration (MAC) set for the working space air by more than 2 times. The article provides a brief overview of improving respiratory protective equipment (RPE) in the United States: development of different Powered Air Purifying Respirators (PAPR); implementation of a personal dust monitor for measuring the dust concentration in real time. PAPR improve gas exchange during breathing and reduce the risk of unfiltered air leakage through gaps in facial contact areas. The effectiveness of the collective prevention equipment depends on many factors. It can be significantly increased via efficient monitoring of dust concentration in the breathing zone of a miner. Russian MAC on air dustiness create favorable conditions for the development of personal dust meters for determining dust concentration in real time. The article provides recommendations for improving dust protection of miners with regard to the international experience.The study was carried out without support. The authors declare no conflicts of interests.

Assessing the Fit of N95 Filtering Facepiece Respirators Fitted with an Ear Loop Strap System: A Pilot Study.

Throughout the COVID-19 pandemic, hundreds of millions of people worldwide have become new users of respiratory protective devices. Facemasks and KN95 respirators utilizing an ear loop straps system (ELSS) have recently become popular among occupational and non-occupational populations. Part of this popularity is due to the ease of wearability as compared with traditional devices utilizing two headbands, one worn over the head and the other behind the neck—a universal strap system used in NIOSH-certified N95 filtering facepiece respirators (FFRs). Some users convert the two-strap configuration to an adjustable ELSS. The first objective of this pilot study was to quantitatively characterize how such a conversion impacts the respirator fit. Additionally, a novel faceseal (NFS) technology, which has been previously demonstrated to enhance the fit of N95 FFRs, was deployed to modify the ELSS-converted N95 FFRs. The second objective of this study was to quantify the fit improvement that results from adding the NFS to the ELSS. The study was conducted by performing the Occupational Safety and Health Administration (OSHA)-approved quantitative fit testing (QNFT) on 16 human subjects featuring different facial shapes and dimensions. Three models of cup-shaped N95 FFRs were tested in three versions: the standard version with manufacturer’s strap system, the ELSS-converted, and the ELSS-converted version modified by adding the NFS. QNFT demonstrated that the fit of an N95 FFR featuring the traditional/standard headbands strap system is negatively impacted when this system is converted to an ELSS. The fit of an ELSS-converted respirator can be significantly improved by the addition of the NFS. We found that the FFR model and the strap system version are significant factors affecting the QNFT-determined respirator fit factor (FF), as well as the OSHA QNFT pass rate (FF ≥100). The findings suggest that the current NFS, if further improved, has a potential for developing a ‘universally fitting’ ELSS-equipped N95 FFR that can be used by the general public, the vast majority of whom do not have access to OSHA fit requirements.

In Silico Fit Evaluation of Additively Manufactured Face Coverings.

In response to the respiratory protection device shortage during the COVID-19 pandemic, the additive manufacturing (AM) community designed and disseminated numerous AM face masks. Questions regarding the effectiveness of AM masks arose because these masks were often designed with limited (if any) functional performance evaluation. In this study, we present a fit evaluation methodology in which AM face masks are virtually donned on a standard digital headform using finite element-based numerical simulations. We then extract contour plots to visualize the contact patches and gaps and quantify the leakage surface area for each mask frame. We also use the methodology to evaluate the effects of adding a foam gasket and variable face mask sizing, and finally propose a series of best practices. Herein, the methodology is focused only on characterizing the fit of AM mask frames and does not considering filter material or overall performance. We found that AM face masks may provide a sufficiently good fit if the sizing is appropriate and if a sealing gasket material is present to fill the gaps between the mask and face. Without these precautions, the rigid nature of AM materials combined with the wide variation in facial morphology likely results in large gaps and insufficient adaptability to varying user conditions which may render the AM face masks ineffective.

Fiber-Based Masks and Respirators: Using Decontamination Methods and Antimicrobial Treatment to Improve Its Reusability during Pandemic

Shortage of personal protective equipment (PPE) is often projected in response to public health emergencies such as infection outbreaks and pandemics. Respiratory protective devices (RPDs), namely medical face masks and respirators, are considered the last defense for the front-line healthcare workers. Cleaning, decontamination and reuse of the disposable RPDs have been accepted by local health authorities during the pandemic period. To contribute to the mitigation of RPD shortage and ensure the safe adoption of decontamination protocols, this review discusses the regulated testing standards and the most commonly studied decontamination methods in the literature. The reuse of RPDs must fulfill three criteria: remove the microbial thread, maintain original function and structural integrity (including fitting tests) and leave no harmful residuals. Decontamination methods such as ultraviolet germicidal irradiation, moist heat and vaporized hydrogen peroxide appeared to be the most promising methods in balancing the above-mentioned criteria. However, the effectiveness of decontamination methods varies depending on the RPDs’ models, materials and design. Therefore, the adoption of protocols needs to be evidence-based with full validation in the local institutes. Additionally, new technology such as antimicrobial treated PPE that can reduce the risks of fomite during donning and doffing process with an extended lifespan should be encouraged. Overall, good training and guidance for appropriate reuse of RPDs are fundamental to ensure their efficiency in protecting front-line healthcare workers.

Evaluation of the Microbiological Effectiveness of Three Accessible Mask Decontamination Methods and Their Impact on Filtration, Air Permeability and Physicochemical Properties.

The need to secure public health and mitigate the environmental impact associated with the massified use of respiratory protective devices (RPD) has been raising awareness for the safe reuse of decontaminated masks by individuals and organizations. Among the decontamination treatments proposed, in this work, three methods with the potential to be adopted by households and organizations of different sizes were analysed: contact with nebulized hydrogen peroxide (H2O2); immersion in commercial bleach (NaClO) (sodium hypochlorite, 0.1% p/v); and contact with steam in microwave steam-sanitizing bags (steam bag). Their decontamination effectiveness was assessed using reference microorganisms following international standards (issued by ISO and FDA). Furthermore, the impact on filtration efficiency, air permeability and several physicochemical and structural characteristics of the masks, were evaluated for untreated masks and after 1, 5 and 10 cycles of treatment. Three types of RPD were analysed: surgical, KN95, and cloth masks. Results demonstrated that the H2O2 protocol sterilized KN95 and surgical masks (reduction of >6 log10 CFUs) and disinfected cloth masks (reduction of >3 log10 CFUs). The NaClO protocol sterilized surgical masks, and disinfected KN95 and cloth masks. Steam bags sterilized KN95 and disinfected surgical and cloth masks. No relevant impact was observed on filtration efficiency.