Journal of Health and Safety at Work

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Introduction: Workers in car manufacturing industry are at risk of a high prevalence of musculoskeletal disorders, especially low back pain. Therefore, in the present study aimed to design and fabricate a portable device to evaluate the low back kinematics and to compare these variables in workers with and without low back pain (LBP) in assembly lines of an automotive industry.
Material and Methods: In the present research workers postures were assessed using OWAS direct observational method. Moreover, simultaneously, prevalence and intensity of low back pain were evaluated by Dutch Musculoskeletal Questionnaire (DMQ) and Visual Analogue Scale (VAS). After fabricating motion analysis device, a field study was conducted using the designed device among 16 volunteers to investigate low back kinematic variables in two groups of workers: LBP and non-LBP.
Results: The results showed that 62.1 percent of all working postures were high risk with corrective action levels of 3 and 4. On average, 86.1 percent of workers experienced LBP in the previous 12 months. Regarding comparison of kinematic variable in the two groups of LBP and non-LBP, workers without LBP had higher degree and duration (in second) of movements (forward flexion, lateral bending, extension, and twisting), as compared to those with LBP. However, only movement range of forward flexion in non-LBP group (mean: 64.29 and SD: 8.41), was significantly higher than those with LBP (mean: 58.97 and SD: 11.34).  
Conclusion: The device can be used as an effective tool in the ergonomics studies in the field of back pain, due to its potential to record the kinematics of the trunk, as well as its lightweight and non-interference with the task. Device’s validity was acceptable based on the comparison of the results of this device with those obtained from inclinometer.

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Introduction: Carpet-weaving is one of the hard and harmful jobs, which affect the health of the workforce. Based on the previously conducted research, musculoskeletal disorders in the neck, shoulder, and lower back regions are common among carpet weavers. This study conducted to investigate the muscle activity of the shoulder and lower back regions in carpet weavers during work on traditional and ergonomic workstations by surface electromyography.
Material and Methods: 18 experienced male weavers with a mean age of 38 and mean weaving experience of 11.1 years participated in this study. Each weaver took part in two trails of 120 min. Surface EMG signal recordings were done during weaving for four muscles (bilaterally in trapezius and erector spine). The RMS and MPF values were extracted from the raw EMG signal to estimate muscle activity and fatigue.
Results: The results obtained from the 5-time intervals indicated the lowered MPF in the ergonomic workstation compared to the traditional one. The result of the mean RMS in most of the recorded times was lower in the ergonomic workstation than that in the traditional one.
Conclusion: According to the results of the study, the modified workstation was well-suited for trapezius muscles, and the traditional one had an advantage for the erector spine muscles.

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Introduction: Climate change and hot processes in the workplaces has led to an increase in the effects of heat stress on employed people, which has become a major concern, especially in tropical and subtropical countries. Early detection of biomarkers in induction of heat stress-related DNA damage can be used in the identification and evaluation of health and safety, including occupational health professionals, as well as to prevent serious diseases caused by heat stress in various occupations with the nature of hot processes or to help different warm seasons of the year. Therefore, this review study was conducted to identify diagnostic biomarkers heat stress induced- DNA damage in occupational exposure.
Material and Methods: Databases such as PubMed, Scopus, Google Scholar, and Web of Science were systematically searched to meet the study’s goals. Moreover, references to relevant publications were examined. Finally, suitable articles were selected and analyzed using the inclusion (studies on different occupations, different biomarkers in hot work environments, all articles published without time limit until the end of April 2022 , and English and Persian language)  and exclusion criteria.
Results: The results of search in databases showed that 9234 articles were found in the initial search. After removing duplicate and unrelated articles, 2209 eligible articles were selected. Based on abstract full-text screening, 7166 studies were excluded, and based on abstract full-text screening, 21 studies were not accessible. Finally, seven articles were selected to be reviewed. The evidence showed that diagnostic biomarkers included the measurement of 8-hydroxy-2-deoxyguanosine (8-OHdG), micronuclei semen quality, heat shock proteins (HSP70), and leukocytes were extracted to heat stress induced- DNA damage in occupational exposure.
Conclusion: Based on a review of studies,  biomarkers identified are suitable for heat stress induced- DNA damage as a result of occupational exposure to extremely high heat climate conditions. Understanding and identifying appropriate biomarkers in inducing DNA damage can help health and safety professionals determine the amount and magnitude of heat stress responses in occupational exposure to different temperatures and take appropriate measures and interventions to control and reduce the hazard effects of thermal stress. This study can also be considered as a preliminary study for research in the future.

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Introduction: In recent years, the manufacture of air purification media, especially nanofiber filters using polymeric materials and the electrospinning method, has received much attention in air pollution control. The production of high-performance media and low-pressure drops is an important issue in air filtration. This study aimed to investigate the feasibility of fabricating electrospinning polyethylene terephthalate (PET) media to abduct submicron and micron particles from the air stream.
Material and Methods: To determine the optimal device conditions in the manufacture of PET media, different weight percentages of a PET polymer solution in a mixture of trifluoroacetic acid and dichloromethane solvents (70:30) were first prepared in a pilot study, and various parameters of the electrospinning device were examined and analyzed along with performing the electrospinning process. The surface and morphological characteristics of the media were evaluated using SEM. The pressure drop and efficiency of particle trapping were assessed using a mask and media pressure by a pressure drop test device.
Results: The optimal electrospinning conditions of the PET polymer solution were obtained at a concentration of 20%. The average diameter of nanofibers PET was 163 ± 600 nm with a pressure drop of 26.33 ± 5.5 pa, and average efficiencies of 97.42 ± 1.67% and 99.85 ± 0.21 were obtained for submicron and micron particles, respectively, with a quality factor (QF) value of 0.1740.
Conclusion: The produced media can abduct and remove particles from the air stream for submicron and micron particles in ranges of 96-99% and 99-100%, respectively, with an average pressure drop of 26.33±5.5 pa.

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Introduction: Numerous studies have been conducted on the development of modern insulators, including nano-insulators. However, a comprehensive study has yet to be performed to review and investigate the thermal properties of these insulators. Consequently, this study aimed to examine the effect of nanomaterials on thermal insulation function.
Material and Methods: In this review, articles were searched for in English databases (PubMed, Web of Science, and ScienceDirect), Persian databases (Magiran, SID), and Google Scholar. The keywords used in the search were Nano Material, Nano Insulation, Thermal Insulation, Thermal Insulator Stability, and Thermal Conductivity in both English and Persian.
Results: Of the 4068 studies identified through search databases, 15 were selected according to the entry criteria. Among the studies, the three types of silicone, composite, and aerogel insulation had the highest frequency (each 26.67%), and SiO2 nanoparticles were the most prevalent nanomaterial (26.67%). According to the studies, the type of nanomaterial used in insulation will improve its properties such as thermal resistance, mechanical strength, dielectric strength, tensile strength, elasticity, and hardness.
Conclusion: The results of this study showed that using nanotechnology could be an effective step in improving the properties of insulation materials, the most important of which is increased thermal resistance. Moreover, nanotechnology insulators can prevent thermal energy loss, reduce costs, and provide safety and comfort.

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Introduction: The COVID-19 pandemic has been a significant global health challenge. Primary care services, such as screening health centers, were crucial in identifying infected individuals. However, these centers were often crowded and posed a high risk to staff and non-COVID-19 patients. This study aims to assess the risk of airborne transmission of SARS-CoV-2 in such settings through simulation.
Material and Methods: In this study, waiting and sampling rooms of a COVID-19 healthcare center were simulated using different scenarios. Then, the Quanta emission rate was estimated using the viral load in the sputum of infected individuals. Finally, the airborne transmission risk of SARS-CoV-2 was determined using the Wells-Riley method for scenarios of wearing and without masks.
Results: The study showed that the Quanta emission rate in an unmodulated speaking activity was higher than other expiratory activities in both units (p <0.001). Also, the total amount of Quanta was slightly higher in the sampling room than in the waiting room, which was not statistically significant. On the other hand, the calculation of transmission risk showed that the probability of airborne virus transmission in the sampling room was higher (about 2 to 8%). In addition, wearing masks reduced the possibility of airborne transmission of the virus significantly (77 to 81%).
Conclusion: This study shows that the level of risk in the sampling and waiting rooms is moderate. Masks also significantly reduce the possibility of airborne transmission of SARS-CoV-2. Taking appropriate health and safety measures such as avoiding crowds, wearing masks, whispering, and monitoring social distancing can reduce the plausibility of airborne transmission of the SARS-CoV-2 virus.
 

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Introduction: Driving has various harmful factors due to its nature, which affect drivers’ health directly and indirectly. Therefore, it is necessary to know the situation and prevalence of these factors in drivers to implement preventive measures.
Material and Methods: This cross-sectional study is a part of a cohort study conducted (2016 to 2018) among the professional drivers of Shahroud, Iran. Data related to background information, blood pressure, height, weight, waist circumference, body mass index, blood factors, hearing loss (dB), respiratory performance indicators, sleep disorders, and accidents were collected from the participants with standard tools and methods.
Results: This study examined 1461 male professional drivers with an average age of 37.30±6.96 years. A total of 426 participants had metabolic syndrome. 797 and 942 people had different degrees of hearing loss, respectively, in the right and left ear. About 129 people had obstructive sleep apnea, and 1330 people had insomnia. Investigations showed that 351 drivers had at least one accident.
Conclusion: This study showed the prevalence of health risk factors in professional drivers at the examined time point. Considering the vital role of drivers in transportation and the country’s economy, it seems necessary to pay more attention to the health of this occupational group. Regular health screening, healthy lifestyle training, improvement of working conditions, and stress management are some interventions that can effectively improve drivers’ health.
 

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Introduction: Workers who work in warm situations need clothes with better thermal regulation. Nowadays, improving the thermal regulation properties of cotton fabric by treating it with phase change materials (PCMs) has been considered. The type of fabric plays an important role in providing thermal comfort. Cotton fabric is the most popular raw material in the textile industry due to its distinctive features. Therefore, this systematic review aims to investigate the effects of PCM nanoencapsulation in commonly used cotton fabrics, including morphology, thermal properties, thermal stability, tensile strength, abrasion resistance, leakage, water absorption, washing ability, and breathability of the fabric, related challenges, and future research trends.
Material and Methods: This research was conducted with the papers obtained from the systematic search in Science Direct, Web of Sciences, Scopus, and PubMed databases. Keywords “nanoencapsulated phase change materials”, “nanoenhanced phase change materials”, “cotton”, “cotton fabric”, and “cotton textiles” were used.
Results: Of the 1251 studies identified through search databases, 13 were selected according to the entry criteria. The results revealed that in all the studies, PCM nanocapsules were successfully synthesized and inserted into the cotton fabric, improving the fabric’s thermal properties. Most studies used in situ polymerization and mini-emulsion polymerization for nanoencapsulation. The pad-dry-cure method was also widely used for applying nanocapsules to cotton fabric.
Conclusion: This systematic review showed that synthesized nanocapsules of phase change materials and applied them to cotton fabric can improve the thermoregulating properties of the fabric. It is suggested to expand the research to design thermoregulating clothes made from treated fabrics and investigate their cooling performance.

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Introduction: Despite advancements in road safety and vehicle design, road accidents remain prevalent, a quarter of which are caused by driver distraction. This issue is particularly critical in the public transport sector, especially among urban bus drivers, as distraction can lead to serious injuries and fatalities. Accordingly, this study explored the factors influencing distraction among urban bus drivers through a qualitative approach and a macroergonomics perspective.
Material and Methods: In this study conducted in 2024 in Tehran, 18 urban bus drivers were selected through cluster sampling. The participants included 10 drivers from bus rapid transit (BRT) system and 8 drivers from non-BRT services. Data were collected through semi-structured interviews with the drivers as well as on-site observations. Subsequently, a directed qualitative content analysis approach, based on the balance theory model, was used to analyze the collected data.
Results: The findings revealed that the primary sources of distraction belonged to six levels of the work system, the most cited of which were environment, tasks, and organization. Specifically, inappropriate behavior of other street users as an environmental factor and the driver’s interactions with passengers as task-related factors were identified as key sources. Additionally, organizational factors such as interactions with supervisors and colleagues, as well as salary issues, were significantly important. The participants very limitedly expressed using mobile phone while driving as a main distractor to their driving.
Conclusion: The current study identified various influential factors, spanning different levels of the work system, affecting bus drivers’ distraction, including generic factors that impact all urban drivers and specific factors that uniquely affect bus drivers. Addressing these factors through providing appropriate education for both passengers and street users along with implementing management strategies in the organization to enhance intra-organizational relationships and organizational support can lead to the safety of the bus drivers.
 

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Introduction: The increasing advancement of technology in the field of digital technology and automation has led to a change in the line of work and job content, and it seems that organizations are pushing their employees towards harder and longer work, which affects the health of employees. This study investigated the impact of job demands and resources on overtime and work-related health through the mediation of workaholism and work engagement.
Material and Methods: The work is a descriptive survey in terms of purpose and nature. The study’s statistical population consisted of employees of Isfahan Metro Company (320 people), of which (175 people) were studied by Simple Random Sampling. To collect the required information, Spence and Robbin’s (1992) Addiction Questionnaire, Lodahl and Kejner’s (1965), Langseth-Eide’s (2019) Perceived Health-Related Questionnaire, and Bryson Bangers’ Caricature Content (1998) were distributed and supplemented based on a Likert scale. A Structural equation model (SEM) was used to test the hypotheses.
Results: The results showed that job demands on workaholism (β=0.394, T=5.969, P <0.05) and job resources had a positive and significant relationship with work engagement (β =0.502, T =7.832, p <0.05), and workaholism and work engagement on the relationship between job demands and resources over time and health. Mediating work-related perceptions (Z= 4.383, Z= 2.189, Z= 3.797). In addition, job resources did not moderate the relationship between job demands and workaholism (β= -0.049, T =1.333, p> 0.05). 
Conclusion: The results of this study showed that there is a distinction between workaholism and work engagement as two different types of hard work (i.e., negative and positive) in the health process in the JD-R model.