Respiratory Protective Equipment Research Articles

Personal protective equipment for preventing asbestos exposure in workers.

Asbestos exposure can lead to asbestos-related diseases. The European Union (EU) has adopted regulations for workplaces where asbestos is present. The EU occupational exposure limit (OEL) for asbestos is 0.1 fibres per cubic centimetre of air (f/cm3) as an eight-hour average. Different types of personal protective equipment (PPE) are available to provide protection and minimise exposure; however, their effectiveness is unclear. To assess the effects of personal protective equipment (PPE), including donning and doffing procedures and individual hygienic behaviour, compared to no availability and use of such equipment or alternative equipment, on asbestos exposure in workers in asbestos demolition and repair work. We searched MEDLINE, Embase, CENTRAL, and Scopus (September 2022), and we checked the reference lists of included studies. We included studies that measured asbestos concentration outside and inside PPE (considering outside concentration a surrogate for no PPE), exposure to asbestos after doffing PPE, donning and doffing errors, nonadherence to regulations, and adverse effects of PPE. Two review authors selected studies, extracted data, and assessed risk of bias using ROBINS-I. We categorised PPE as full-face filtering masks, supplied air respirators (SARs), and powered air-purifying respirators (PAPRs). Values for asbestos outside and inside PPE were transformed to logarithmic values for random-effects meta-analysis. Pooled logarithmic mean differences (MDs) were exponentiated to obtain the ratio of means (RoM) and 95% confidence interval (95% CI). The RoM shows the degree of protection provided by the respirators (workplace protection factor). Since the RoM is likely to be much higher at higher outside concentrations, we presented separate results according to the outside asbestos concentration, as follows. • Below 0.01 f/cm3 (band 1) • 0.01 f/cm3 to below 0.1 f/cm3 (band 2) • 0.1 f/cm3 to below 1 f/cm3 (band 3) • 1 f/cm3 to below 10 f/cm3 (band 4) • 10 f/cm3 to below 100 f/cm3 (band 5) • 100 f/cm3 to below 1000 f/cm3 (band 6) Additionally, we determined whether the inside concentrations per respirator and concentration band complied with the current EU OEL (0.1 f/cm3) and proposed EU OEL (0.01 f/cm3). We identified six studies that measured asbestos concentrations outside and inside respiratory protective equipment (RPE) and one cross-over study that compared the effect of two different coveralls on body temperature. No studies evaluated the remaining predefined outcomes. Most studies were at overall moderate risk of bias due to insufficient reporting. The cross-over study was at high risk of bias. Full-face filtering masks Two studies evaluated full-face filtering masks. They provided insufficient data for band 1 and band 6. The results for the remaining bands were as follows. • Band 2: RoM 19 (95% CI 17.6 to 20.1; 1 study, 3 measurements; moderate certainty) • Band 3: RoM 69 (95% CI 26.6 to 175.9; 2 studies, 17 measurements; very low certainty) • Band 4: RoM 455 (95% CI 270.4 to 765.1; 1 study, 16 measurements; low certainty) • Band 5: RoM 2752 (95% CI 1236.5 to 6063.2;1 study, 3 measurements; low certainty) The inside measurements in band 5 did not comply with the EU OEL of 0.1 f/cm3, and no inside measurements complied with the proposed EU OEL of 0.01 f/cm3. Supplied air respirators Two studies evaluated supplied air respirators. They provided no data for band 6. The results for the remaining bands were as follows. • Band 1: RoM 11 (95% CI 7.6 to 14.9; 1 study, 134 measurements; moderate certainty) • Band 2: RoM 63 (95% CI 43.8 to 90.9; 1 study, 17 measurements; moderate certainty) • Band 3: RoM 528 (95% CI 368.7 to 757.5; 1 study, 38 measurements; moderate certainty) • Band 4: RoM 4638 (95% CI 3071.7 to 7044.5; 1 study, 49 measurements; moderate certainty) • Band 5: RoM 26,134 (16,647.2 to 41,357.1; 1 study, 22 measurements; moderate certainty) All inside measurements complied with the current OEL of 0.1 f/cm3 and the proposed OEL of 0.01 f/cm3. Powered air-purifying respirators Three studies evaluated PAPRs. The results per band were as follows. • Band 1: RoM 8 (95% CI 3.7 to 19.1; 1 study, 23 measurements; moderate certainty) • Band 2: RoM 90 (95% CI 64.7 to 126.5; 1 study, 17 measurements; moderate certainty) • Band 3: RoM 104 (95% CI 23.1 to 464.1; 3 studies, 14 measurements; very low certainty) • Band 4: RoM 706 (95% CI 219.2 to 2253.0; 2 studies, 43 measurements; very low certainty) • Band 5: RoM 1366 (544.6 to 3428.9; 2 studies, 8 measurements; low certainty) • Band 6: RoM 18,958 (95% CI 4023.9 to 90,219.4; 2 studies, 13 measurements; very low certainty) All inside measurements complied with the 0.1 f/cm3 OEL when the outside concentration was below 10 f/cm3 (band 1 to band 4). From band 3, no measurements complied with the proposed OEL of 0.01 f/cm3. Different types of coveralls One study reported the adverse effects of coveralls. A polyethylene suit may increase the body temperature more than a ventilated impermeable polyvinyl (PVC) coverall, but the evidence is very uncertain (MD 0.17 °C, 95% CI -0.08 to 0.42; 1 study, 11 participants; very low certainty). Where the outside asbestos concentration is below 0.1 f/cm3, SARS and PAPRs likely reduce exposure to below the proposed OEL of 0.01 f/cm3. For outside concentrations up to 10 f/cm3, all respirators may reduce exposure below the current OEL, but only SAR also below the proposed OEL. In band 5 (10 to < 100 f/cm3), full-face filtering masks may not reduce asbestos exposure below either OEL, SARs likely reduce exposure below both OELs, and there were no data for PAPRs. In band 6 (100 f/cm3 to < 1000 f/cm3), PAPRs may not reduce exposure below either OEL, and there were no data for full-face filtering masks or SARs. Some coveralls may increase body temperature more than others. Randomised studies are needed to directly compare PAPRs and SARs at higher asbestos concentrations and to assess adverse effects. Future studies should assess the effects of doffing procedures.

Assessment of Left Lung Remodeling With Magnetic Resonance Imaging in a Murine Model Following Exposure to Douglas Fir Smoke.

Wildland firefighters (WLFFs) experience lung function decline due to occupational exposure to fire smoke. WLFFs typically do not wear respiratory personal protective equipment, and if they do, it is a simple bandana, which is not effective at filtering smoke. To pinpoint the biological underpinnings of abnormal respiratory function following 3-7 years of WLFF service, we exposed mice to Douglas fir smoke (DFS) over 8 weeks. Following exposure, we assessed changes in lung structure through Magnetic Resonance Imaging (MRI) and histological analysis, which was supported by immunohistochemistry staining. With MRI, we found that the signal decay time, T2*, from ultrashort echo time (UTE) images was significantly shorter in mice exposed to DFS compared to air controls. In addition, the variation in T2* was more heterogeneously distributed throughout the left lung in DFS-exposed mice, compared to air controls. As confirmed by histological analysis, shorter T2* was caused by larger parenchyma airspace sizes and not fibrotic remodeling. Destruction of the alveolar spaces was likely due to inflammation, as measured by an influx of CD68+ macrophages and destruction due to enhanced neutrophil elastase. In addition, measurements of airspace dimensions from histology were more heterogeneously distributed throughout the lung, corroborating the enhanced relative dispersion of T2*. Findings from this study suggest that the decline in lung function observed in WLFFs may be due to emphysema-like changes in the lung, which can be quantified with MRI.

Self-reported exposure to dust and diesel exhaust, respiratory symptoms, and use of respiratory protective equipment among Arctic miners

ABSTRACT Arctic miners face significant risks from diesel exhaust and dust exposure, potentially leading to adverse respiratory health. Employers must limit harmful exposures, using personal protective equipment (PPE) as a last line of defense. This study explored the association between reported respiratory exposure and symptoms, and PPE training and usage. Data from the MineHealth study (2012–2014) included a total of 453 Arctic open pit miners in Norway, Sweden, and Finland. Participants answered questions on exposure to dust and diesel exhaust, respiratory symptoms, and PPE use, in addition to age, gender, BMI, smoking, and self-rated health. Estimated exposure to dust was common, reported by 91%, 80%, and 82% and that of diesel exhaust by 84%, 43%, and 47% of workers in Sweden, Finland, and Norway, respectively. Reported dust exposure was significantly related to respiratory symptoms (OR 2.2, 95% CI 1.3–3.7), diesel exposure increased the occurrence of wheezing (OR 2.6, 95% CI 1.3–5.4). PPE use varied between the studied mines. Non-use was common and related to reduced visibility, wetness, skin irritation and fogging of the respiratory PPE. Future research should employ more precise exposure assessment, respiratory function as well as explore the reasons behind the non-compliance of PPE use.

Welding fume exposure and prevalence of chronic respiratory symptoms among welders in micro- and small-scale enterprise in Akaki Kality sub-city, Addis Ababa, Ethiopia: a comparative cross-sectional study.

Exposure to welding fumes can lead to different respiratory health disorders, including lung cancer, due to long-term exposures. In Ethiopia, large numbers of people are engaged in the welding sector. Often, these workers are exposed to welding fumes at their workplaces, however, the level of exposure and its health effects have never been studied. To measure the level of personal welding fume exposure and assess chronic respiratory symptoms and associated factors, among micro and small-scale enterprise metal workshop workers, in Akaki Kality Sub city, Ethiopia. A comparative cross-sectional study involving 226 welders and 217 controls. Chronic respiratory symptoms were assessed using a standardized questionnaire adopted from the American Thoracic Society (ATS). Welding fumes were collected from the welder's breathing zone using 37mm close-faced plastic cassettes fitted with Polyvinyl Chloride (PVC) filters connected to Casella pumps at an airflow rate of 2L/min. The overall prevalence of chronic respiratory symptoms among welders and controls were 54 (23.9%) and 20 (9.2%) respectively. The geometric mean and geometric standard deviation (GSD) of personal welding fume exposure, among welders was 5.98 mg/m3 (± GSD = 1.54). In this study, 53.3% of the samples exceeded the Occupational Exposure Limit defined by the American Conference of Governmental Industrial Hygiene. Chronic respiratory symptoms were significantly associated with educational status (Adjusted Odds Ratio (AOR): 5.11, 95% CI: 1.35, 19.33), respiratory protective equipment use (AOR: 3.33, 95% CI: 1.52, 7.31), safety training (AOR: 2.41, 95% CI: 1.10, 5.28), smoking (AOR:3.57, 95% CI: 1.54, 8.23), welding machine maintenance (AOR: 1.87, 95% CI: 1.01, 3.59) and welding site (i.e. indoors vs. outdoor) (AOR: 6.85. 95% CI: 2.36, 19.89). The prevalence of chronic respiratory symptoms among welding workers was significantly higher than controls. More than half of the samples exceeded the Occupational Exposure Limit. Educational status, implementation of safety training, and welding sites were significantly associated with chronic respiratory symptoms. The results suggested a need to reduce welding fume exposure to improve the respiratory health of the workers.

Gas mask wearing detection based on Faster R-CNN

Gas masks are essential respiratory protective equipment commonly used by laborers who work in harsh environments. However, respiratory diseases and accidents can occur due to the absence of gas masks. To prevent these accidents, this paper developed an object detector that uses convolutional neural networks (CNNs) to detect whether workers are wearing gas masks. To achieve this goal, a gas mask detection dataset was constructed derived from real industrial scenarios and Faster R-CNN was improved for gas mask wearing detection. Firstly, to address the multi-scale problem in real scenes, the Feature Pyramid Network was introduced into Faster R-CNN to effectively fuse features between different levels and improve the detection ability of small objects. Secondly, the Online Hard Sample Mining algorithm was used to alleviate the class imbalance problems in the dataset. Finally, Mixup and Mosaic were used in the training process to augment the data and make the model better adapt to different scenes and complex backgrounds. After multiple experiments, the combination of the three optimization strategies improved the mAP 0.5 : 0.95 by 23.2%. This work is an initial attempt at gas mask wearing detection and there is still much room for improvement in terms of model and dataset.

Improved non-woven surgical masks with nanostructured cellulosic reinforcement from sugarcane bagasse waste

The COVID-19 pandemic has brought concerns about the efficacy of respiratory protection equipment, primarily due to their widespread usage during this period. Among the various types of face masks, the N95, PFF3, and PFF2 surgical masks have gained great prominence due to their efficiency, despite the discomfort they may cause. Therefore, thinking of a cost-effective and more comfortable solution, this work aimed to reinforce non-woven face masks with cellulose nanofibrils (CNFs), to improve their filtration efficiency. For this, CNFs were produced using the mechanical processing of sugarcane bagasse (SCB) residues, which underwent plain alkaline pretreatment (CNF-PA) or alkaline pretreatment followed by enzymatic pretreatment (CNF-AE). It was observed that the CNF-AE films developed better characteristics regarding the contact angle, density, porosity, transmittance and transparency as well as vapor permeability compared to the CNF-PA films. The application of CNF on non-woven masks was performed using the spray technique. Bacterial filtration analysis showed filtration efficiency of 99.68% and 99.80% for masks that were coated with CNF-PA and CNF-AE, respectively. Whereas uncoated masks presented a filtration efficiency below 95%, which is the minimum required value. The masks obtained breathability values of 79.75 Pa/cm2 and 106.00 Pa/cm2 for CNF-AE and CNF-PA, respectively, whereas the uncoated masks showed values below 30.00 Pa/cm2. This work shows that the CNF obtained from SCB present good barrier capabilities and should be used for this purpose, especially on protective masks.

Determination of the Convergence of Intra-Laboratory Measurements of Dust Content on a Construction Site

Introduction. Intra-laboratory comparison tests play an important role in ensuring the quality and reliability of research outcomes in laboratories. These tests allow researchers to evaluate the accuracy and reproducibility of the methods they use in their work, as well as to identify potential sources of error and inconsistency. The results of these tests are shared with experts to confirm competence within the accreditation. Typically, comparison tests are carried out in laboratory conditions in a familiar and calm environment for the testers. However, when laboratories conduct research as part of a special assessment of working conditions (SAWC) they are required to conduct on-site comparisons at real-world facilities, where customers may unwittingly disrupt the process and directly affecting the quality of the measurements. The aim of this study is to evaluate the quality of on-site intra-laboratory comparison tests using the example of determining the dust content in a bricklayer's work environment on a construction site, and to determine the minimum number of measurements necessary and sufficient for this purpose.Materials and Methods. To determine the dustiness of the bricklayer's workplace, a weighing method was used. This involved collecting dust on filters and then weighing them to determine the concentration. The quality assessment of intra-laboratory tests was conducted in accordance with GOST R ISO 5725-1-2002 "Accuracy (trueness and precision) of measurement methods and results. Part 1. General principles and definitions".Results. At the bricklayer's workplace, a 1.6-fold excess of the one-time maximum permissible dust concentration was detected. The average dust concentration at the workplace under study was: Kp2 = 9.57 ± 0.81 mg/m3, the convergence of the results obtained was r = 8.68 %, the relative error δ = 8.50 %. It was revealed that the maximum allowable difference between the results of the two tests was 0.84 mg/m3. The difference in direct measurements of the mass of the two samples should be no more than 0.1 mg.Discussion and Conclusion. The results obtained demonstrated the possibility of conducting a minimum number of measurements that, under reproducible conditions, are considered satisfactory and could be provided to experts for confirming the competence of the laboratory. As part of a special assessment of working conditions, employees of the object under study are recommended to use personal respiratory protection equipment that offers protection against highly dispersed dust particles.

Use, failure, and non-compliance of respiratory personal protective equipment and risk of upper respiratory tract infections-A longitudinal repeated measurement study during the COVID-19 pandemic among healthcare workers in Denmark.

Upper respiratory tract infections (URTI) are common and a common cause of sick-leave for healthcare workers, and furthermore pose a threat especially for patients susceptible to other diseases. Sufficient use of respiratory protective equipment (RPE) may protect both the workers and the patients. The COVID-19 pandemic provided a unique opportunity to study the association between use of RPE and URTI in a real-life setting. The aim of this study was to examine if failure of RPE or non-compliance with RPE guidelines increases the risk of non-COVID-19 URTI symptoms among healthcare workers. In a longitudinal cohort study, we collected self-reported data daily on work tasks, use of RPE, and URTI symptoms among healthcare workers with patient contact in 2 Danish Regions in 2 time periods during the COVID-19 pandemic. The association between failure of RPE or non-compliance with RPE guidelines and URTI symptoms was analyzed separately by generalized linear models. Persons tested positive for severe acute respiratory syndrome coronavirus 2 were censored from the analyses. The 2 waves of data collection were analyzed separately, as there were differences in recommendations of RPE during the 2 waves. We found that for healthcare workers performing work tasks with a risk of transmission of viruses or bacteria, failure of RPE was associated with an increased risk of URTI symptoms, RR: 1.65[0.53-5.14] in wave 1 and RR: 1.30[0.56-3.03] in wave 2. Also non-compliance with RPE guidelines was associated with an increased risk of URTI symptoms compared to the use of RPE in wave 1, RR: 1.28[0.87-1.87] and wave 2, RR: 1.39[1.01-1.91]. Stratifying on high- versus low-risk tasks showed that the risk related to failure and non-compliance was primarily associated with high-risk tasks, although not statistically significant. The study was conducted during the COVID-19 pandemic and thus may be affected by other preventive measures in society. However, this gave the opportunity to study the use of RPE in a real-life setting, also in departments that did not previously use RPE. The circumstances in the 2 time periods of data collection differed and were analyzed separately and thus the sample size was limited and affected the precision of the estimates. Failures of RPE and non-compliance with RPE guidelines may increase the risk of URTI, compared to those who reported use of RPE as recommended. The implications of these findings are that the use of RPE to prevent URTI could be considered, especially while performing high-risk tasks where other prevention strategies are not achievable.

Effectiveness of respiratory protective equipment on source control of exhaled pollutants

Respiratory protective equipment (RPE) is used either to protect the wearer (protection effect during inhalation) or to protect others from potential transmission of pathogens from the wearer (source control effect during exhalation). Inhalation and exhalation are two processes that generate microenvironments with different characteristics inside the RPE. In order to quantitatively evaluate the source control effectiveness (SCE) of RPE, the gap size between the RPE and the face was measured using volunteers, and the tracer-gas-based method and aerosol-based method were applied to visualize and quantify the dispersion of exhaled pollutants through the face mask and the gap using a manikin. The tracer-gas-based method (using CO2) largely overestimated the concentration of exhaled pollutants in front of the RPE. The SCE of RPE was 76–99% for aerosols and 79–92% for tracer gas. The top gap of the face mask was the dominant leakage route of exhaled pollutants. When the size of the top gap increased from 8 mm to 20 mm, the SCE for aerosols smaller than 1 μm decreased by about 15%. The SCE of the combined RPE with an N95 mask and a face shield was about 7% higher than that for an N95 mask alone. Increasing the pulmonary ventilation rate from 6 to 13 L/min and the respiratory cycle from 3 to 5 s decreased the SCE of RPE by 16% and 9%, respectively, indicating the importance of considering the activity level. The data obtained provides a basis for evaluating and improving the performance of RPE.

Virtual fit and design improvements of a filtering half-mask for sub-adult wearers

The recent pandemic has shown that protecting the general population from hazardous substances or pathogens can be a challenging and urgent task. The key element to adequate protection is appropriately sized, well-fitted and sufficiently distributed personal protective equipment (PPE). While these conditions are followed for adult PPE wearers, they are less considered when it comes to protecting subadults. In this study, the assessment of the fit and design improvements of a 3D-printed facial half mask for subadult wearers (4–18 years) is designed. The target population was represented by 1137 subadults, aged 4.06–18.94 years, for whom 3D face models were acquired. The half mask tested, which was originally provided in one subadult size, did not fit appropriately the target population. This finding prompted the creation of four size categories using the age-dependent distribution of the centroid size calculated from 7 facial landmarks. For each size category, a modified half-mask virtual design was created, including resizing and reshaping, and fit was evaluated visually and numerically using averaged and random 3D face representatives. Practitioner summary: The reason for this study was to describe procedures which led to design improvement of an existing half-mask and provide respiratory protection for subadults. To address this, fit was assessed using an innovative metric approach. Four sizes were then created based on centroid size, resulting in improved fit and design. Abbreviations: CH: cheilion landmark; CS: centroid size; EX: exocanthion landmark; GN: gnathion landmark; N: nasion landmark; PPE: personal protective equipment; PR: pronasale landmark; RPE: respiratory protective equipment

Features of occupational diseases caused by fibrogenic aerosols at enterprises in the Arctic

Introduction. Industrial dust aerosols with a predominantly fibrogenic effect remain an important risk factor for the health of the working population in the Arctic.&#x0D; The study aims to explore the features of the development, structure and prevalence of occupational diseases caused by fibrogenic aerosols at enterprises in the Arctic.&#x0D; Materials and methods. The authors have studied the archival data of the socio-hygienic monitoring "Working conditions and occupational morbidity" and the register of extracts from occupational disease records (Order of the Ministry of Health of the Russian Federation No. 176 dated 05/28/2001).&#x0D; Results. At enterprises in the Arctic in 2007–2021, fibrogenic aerosols ranked ninth (4.8%) in terms of the number of exposed workers, and fifth among harmful production factors in terms of the number of occupational diseases caused by their action (491 cases or 9.1%). They were characterized by the formation of employees of coal enterprises (83.1%), dominance in the structure of the pathology of chronic bronchitis (87.7%), etiological association with weakly fibrogenic aerosols (94.3%). The risk of diseases from exposure to fibrogenic aerosols in miners was higher than in metallurgical workers (RR=12.9; 95% CI 9.63–17.26; p&lt;0.001), construction (RR=11.7; 95% CI 10.78–19.11; p&lt;0.0001) and transport (RR=31.3; 95% CI 10.11–77.19; p&lt;0.001) enterprises. For 15 years, researchers have observed a decrease in the number of diseases caused by the action of fibrogenic aerosols, and the risk of their development in 2007–2009 was higher than in 2019–2021: RR=2.10; 95% CI 1.19–3.71; p=0.009.&#x0D; Conclusion. In the prevention of occupational pathology from the effects of fibrogenic aerosols, the priority remains to improve dust suppression methods and respiratory protection equipment for sinkers, miners of the treatment face, machinists of mining machines and other specialists of coal mining enterprises in the Arctic

Health and Safety Executive research on wood dust exposure controls in British manufacturing.

To generate new intelligence on occupational exposure to wood dust in woodworking manufacturing activities in Britain, the Health and Safety Executive (HSE) performed 22 occupational hygiene site visits to assess exposure and exposure controls between 2014 and 2017. The work aimed to characterise good practice and therefore sites with a poor health and safety record, as identified from HSE inspection records, were not invited to participate. Sites selected covered furniture production, joinery, saw milling, and boat building and repair. Twenty-three follow-up telephone interviews were also carried out across 15 of the companies with supervisors and managers to explore how they tried to promote good practice among the workforce, and if there are any potential challenges encountered. The aim of the interviews was to gain a better understanding of how to enable organisations to improve the management of wood dust exposure. This study found that 6.0% of all wood dust exposure measurements (15 out of 252) were above 5 mg/m³, and 17.6% of exposures to hardwood dust or mixtures of hardwood and softwood dust (38 out of 216) were above 3 mg/m³ (the then current and future workplace exposure limits). Sanding, cleaning, and maintenance activities were of particular concern. Improvements to exposure controls are required, in particular, improvements to local exhaust ventilation controls for hand-held power tools and hand sanding. The management, selection, and use of respiratory protective equipment were poor. All the managers and supervisors recognised that exposure to wood dust can pose serious health risks, and that controls were crucial to protecting workers' health. The findings from the telephone interviews suggest that supervision and provision of information about the health effects of exposure to wood dust were common approaches that organisations used to raise awareness and promote good practice, in relation to managing wood dust exposure. Worker attitudes towards controls, such as perceptions that they hinder task completion and habitual ways of working, were identified as factors influencing the use of controls. Risk communication approaches that focus on increasing workers' awareness of their susceptibility to ill-health using credible sources, such as peers, can help enhance the uptake of messages on the use of controls. Financial constraints were identified as a challenge to improving the control of wood dust, particularly for small companies.

A mathematical model for accurately predicting face mask wearer’s inhalation exposure to self-exhaled and external pollutants

Face masks reduce the wearers’ inhalation exposure to external pollutants, but intensifying the exposure to their self-exhaled pollutants. To quantify the wearers’ inhalation exposure to the two sources of pollutants, a mathematical model for transient-state conditions was firstly established and scientifically validated, with an average relative deviation of only 3 % from the experimental data and only 6 % from the validated CFD simulated results. Proportion of leakage flow rate via gap (γ) was mainly affected by breathing flow rate (Lexh/inh) and gap’s area (Sg), followed by face mask’s surface area (Sm) and thickness (Mm). The 7 L/min of Lexh/inh led to the maximum inhalation fraction (IF) of self-exhaled pollutants at about 54 %, implying that wearing face masks poses a threat to the wearer’s health. When face mask’s volume increased from 50 mL to 150 mL, the relative intake dose (ID∗) of external pollutants decreased by 0.12 but the IF of self-exhaled pollutants increased by 9 %. When face mask’s filtration efficiency increased from 10 % to 90 %, the IF of self-exhaled pollutants and the ID∗¯ of external pollutants decreased by 13 % and 0.23, respectively. The increase of 0.80 in γ decreased the IF of self-exhaled pollutants by 8 % but increased ID∗¯ of external pollutants by 0.19, implying that protective performance always contradicts on the inhalation exposure to self-exhaled pollutants. The model established provides a new method to evaluate the performance of face masks rapidly and accurately, and further benefits the improvement of face masks and even other respiratory protective equipment.

Respiratory protective equipment fit tests for researchers at the national synchrotron radiation research center

Researchers at the National Synchrotron Radiation Research Center should use respiratory protective equipment to prevent respiratory damage caused by gases, steam, solvents, chemicals, materials containing toxic substances, and oxygen-deficient environments. Those working with organic matter and certain chemical substances and those exposed to occupation dust should use respiratory protective gear to ensure their health. This study conducted qualitative and quantitative fit tests for various mask brands and sizes, namely 3M-9042, N95-9211, P95-8576, and 3M-6200 masks. The gear worn by all 18 participants in the qualitative fit test passed. By contrast, the gear worn by 12 of the 15 participants in the quantitative test passed; the failure of the remaining gear was due to differences in face shape. The N95-9211 mask can be used in three-piece protective gear because it exhibited a tight fit. Additionally, the 3M-6200 negative-pressure half-face mask exhibited the most satisfactory fit and can be used in protective gear.

Pooled Prevalence of Byssinosis in India: A Systematic Review and Meta-analysis

Abstract Byssinosis is an occupational lung disease affecting textile workers exposed to cotton, jute and hemp dust. It causes symptoms like cough, breathlessness, and wheezing which is more during Mondays. Diagnosis is mainly clinical. The true burden of byssinosis in India remains unknown, and this systematic review and meta-analysis (SR-MA) aims to estimate its prevalence among textile industry workers in India. This study was registered in PROSPERO. The search spanned from January 2000 to September 2023, focusing on observational studies that met specific criteria. Two independent reviewers screened the literature, extracted relevant data, and assessed the risk of bias. Statistical analysis included a random effects model, assessment of heterogeneity and publication bias. Eighteen studies (5678 individuals) were included in the analysis. Byssinosis diagnosis was based on Schilling’s criteria in the majority of studies. Seven studies had low risk of bias, three had high risk, and the rest were moderate. There was no significant publication bias. The pooled prevalence of byssinosis was 24% (95% CI = 13%-36%) with high heterogeneity (I 2 = 99.02%). Sub-group analysis of studies with low risk of bias showed a prevalence of 20% (95% CI = 11% - 29%). Extrapolation of these findings to India suggests that about 10 million people are affected by byssinosis. The authors recommend development and practice of tailored health surveillance guidelines and the promotion of respiratory protective equipment (RPE) among those employed in textile industries.

Продвижение пожарных в зонах повышенных температур

Purpose. This article addresses the issue of the impact of hazardous fire factors (HFF) on firefighters in an environment unsuitable for breathing. Currently, there are no regulatory criteria for permissible exposure of firefighters to HFF, particularly elevated ambient temperatures. To reach the position for deploying fire extinguishing agents, firefighters are forced to traverse a zone of elevated temperatures, and in some cases, remain in it for some time. The authors have studied the effect of elevated temperatures during firefighting on the ability of smoke divers to advance towards the fire zone in personal respiratory and vision protective equipment, as well as in firefighting gear. Methods. A field experiment was conducted to assess the ability of firefighters to advance in high-temperature zones. Temperature values and corresponding sensations of firefighters were studied to identify the peculiarities of the smoke divers teams' (SDT) work when advancing in different zones of elevated temperatures. Findings. The experiment demonstrated the peculiarities of advancement of smoke divers in high-temperature zones and the limiting conditions thereof. The experiment was conducted under conditions approximating real ones, created in the “Ugolyok” training complex. The analysis conducted based on the experiment results allowed determining the range of tolerance for elevated temperatures by firefighters, depending on the protective properties of firefighting gear, their own tolerance threshold, experience working in high-temperature zones, and the use of other protective methods. For instance, at temperatures of 150–180°C, SDT were able to reach the fire zone, but they reported feeling the temperature already, making it difficult to work near the fire zone for an extended period. When the temperature rose to 280–350°C, poorly protected areas (knees and elbows in contact with firefighting gear, hands, head, and legs between the boot shin guards and liners) began to burn, making advancement difficult and unsafe for the lives and health of smoke divers at such temperature levels. Research application field. The results of the conducted experiment justify measures aimed at increasing the effectiveness of personnel work in high-temperature zones and minimizing risks during the performance of professional tasks. The results can also be used in expert examinations of firefighting organization (e.g., in determining the possibility of advancing SDT into various zones). Conclusions. The authors have more thoroughly studied the mechanism of SDT work when advancing under the influence of hazardous fire factors, describing the sensations of smoke divers under different temperature conditions. The conducted experiment allowed determining the levels of tolerance for elevated temperatures by firefighters in firefighting gear and respiratory and vision protective equipment.

MINIMISATION OF THE NEGATIVE EFFECTS OF EXPOSURE TO OF THE IMPACT OF INCENDIARY WEAPONS ON THE CIVILIAN POPULATION

Incendiary weapons are understood as incendiary substances and means of their combat use. Incendiary weapons are intended to defeat personnel, destroy and damage weapons and military equipment, structures and other objects. Throughout the history of warfare, incendiary weapons have caused suffering to millions of people who were not directly involved in the armed conflict. The situation remains unchanged today, with civilians being killed, injured or disabled for life, often losing loved ones or property as a result of the use of incendiary weapons. Virtually all existing publications on protecting people from incendiary weapons are focused on the protection of military personnel. There is very little information on how to protect civilians.&#x0D; An algorithm of actions for a civilian to minimise the negative effects of the impact of incendiary weapons has been developed. This algorithm includes the following actions: timely warn others about the use of incendiary weapons, help and, if necessary, guide the actions of those who need it (elderly people, children, people in panic); take shelter in the nearest civil defence structure, shelter (shelter). In the absence of such facilities, use underground passages, subway stations, basements and entrances of residential buildings, and shops; in the event of a sudden attack and the absence of nearby civil defence structures, shelters and refuges, use the protective properties of vehicles. It should be borne in mind that cars, buses and vehicles covered with tents provide only short-term protection, as they quickly catch fire.&#x0D; Use the protective properties of the terrain (uneven terrain, pits, covered public transport stops, fences, benches, curbs) to reduce the chance of pieces of incendiary material falling on a person; if it is impossible to find any shelter, lie down on the ground. Use local materials available to protect the surface of the body from incendiary weapons (suitcases, backpacks, billboards, paper clips). Burning surfaces are immediately thrown off and extinguished. Use personal respiratory protection equipment (handkerchiefs soaked in liquid, pieces of cloth) and skin protection equipment (cotton jackets, half-coats, raincoats, which are short-term protection equipment and should be immediately discarded if they come in contact with pieces of incendiary mixture); provide first aid to the victims. First aid shall begin with extinguishing by the victims themselves or with the help of surrounding inflammable substances that have got on their skin or clothing. At this point (period), no loss of self-control is allowed. To extinguish a small amount of inflammable substance, it is necessary to cover the burning area with a sleeve, jacket, wet clay, earth or snow. If several pieces of clothing are burning on your person, the flames should be knocked down by rolling them successively on the ground.&#x0D; If a significant amount of inflammable substance gets on a person, extinguishing is carried out by covering the victim with clothes, pouring water, covering with earth or sand.

Antimicrobial activity of silver-copper coating against aerosols containing surrogate respiratory viruses and bacteria

The transmission of bacteria and respiratory viruses through expelled saliva microdroplets and aerosols is a significant concern for healthcare workers, further highlighted during the SARS-CoV-2 pandemic. To address this issue, the development of nanomaterials with antimicrobial properties for use as nanolayers in respiratory protection equipment, such as facemasks or respirators, has emerged as a potential solution. In this study, a silver and copper nanolayer called SakCu® was deposited on one side of a spun-bond polypropylene fabric using the magnetron sputtering technique. The antibacterial and antiviral activity of the AgCu nanolayer was evaluated against droplets falling on the material and aerosols passing through it. The effectiveness of the nanolayer was assessed by measuring viral loads of the enveloped virus SARS-CoV-2 and viability assays using respiratory surrogate viruses, including PaMx54, PaMx60, PaMx61 (ssRNA, Leviviridae), and PhiX174 (ssDNA, Microviridae) as representatives of non-enveloped viruses. Colony forming unit (CFU) determination was employed to evaluate the survival of aerobic and anaerobic bacteria. The results demonstrated a nearly exponential reduction in SARS-CoV-2 viral load, achieving complete viral load reduction after 24 hours of contact incubation with the AgCu nanolayer. Viability assays with the surrogate viruses showed a significant reduction in viral replication between 2–4 hours after contact. The simulated viral filtration system demonstrated inhibition of viral replication ranging from 39% to 64%. The viability assays with PhiX174 exhibited a 2-log reduction in viral replication after 24 hours of contact and a 16.31% inhibition in viral filtration assays. Bacterial growth inhibition varied depending on the species, with reductions ranging from 70% to 92% for aerobic bacteria and over 90% for anaerobic strains. In conclusion, the AgCu nanolayer displayed high bactericidal and antiviral activity in contact and aerosol conditions. Therefore, it holds the potential for incorporation into personal protective equipment to effectively reduce and prevent the transmission of aerosol-borne pathogenic bacteria and respiratory viruses.

Post-acute COVID-19 complications in UK doctors: results of a cross-sectional survey.

As a consequence of their occupation, doctors and other healthcare workers were at higher risk of contracting coronavirus disease 2019 (COVID-19), and more likely to experience severe disease compared to the general population. However, systematic information on post-acute COVID complications in doctors is very limited. This study aimed to determine the symptoms, perceived determinants, health and occupational impact, and consequent needs relating to post-acute COVID complications in UK doctors. An online cross-sectional survey was distributed to UK doctors self-identifying as having Long COVID or other post-acute COVID complications. Of 795 responses, 603 fulfilled the inclusion criteria of being a UK-based medical doctor experiencing one or more post-acute COVID complications. Twenty-eight per cent reported a lack of adequate Respiratory Protective Equipment at the time of contracting COVID-19. Eighteen per cent of eligible respondents reported that they had been unable to return to work since acquiring COVID. Post-acute COVID (Long COVID) in UK doctors is a substantial burden for respondents to our questionnaire. The results indicated that insufficient respiratory protection could have contributed to occupational disease, with COVID-19 being contracted in the workplace, and resultant post-COVID complications. Although it may be too late to address the perceived determinants of inadequate protection for those already suffering with Long COVID, more investment is needed in rehabilitation and support of those afflicted.

COVID-19 in Workplace Settings: Lessons Learned for Occupational Medicine in the UK.

This paper addresses lessons learned from the COVID-19 pandemic from a UK Occupational Medicine perspective to permit comparison with other national accounts. In spite of good prior research and statute, the necessary resources to protect workers' health were seriously lacking when the pandemic struck. Weak public health guidance, which did not recognise dominant airborne transmission, was applied to workplaces, leaving workers and others unprotected, especially in respect to Respiratory Protective Equipment (RPE). The Health and Safety Executive (HSE) as regulator was lacking, for example, in not producing guidance to protect HealthCare Workers (HCW) who were amongst the most at risk. The UK COVID-19 Public Inquiry should address shortcomings such as these, but recommendations must be accompanied by robust means to ensure appropriate implementation. These should range from substantial measures to improve indoor air quality, to a permanent pandemic management organization with adequate resources. The enforcing authority has to be obliged to publish more specific workplace guidance than the public health authorities. Occupational medicine as a discipline needs to be better prepared, and hence to assert its responsibility towards high standards of workers' health protection. Future research has to include investigating the best means of mitigation against airborne infection and the management of post-acute covid sequelae.