مجله بهداشت و ایمنی کار
سال سیزدهم شماره 3 (پاییز 1402)

Strategic management involves determining the organization’s direction, preparing a strategic vision and mission statement, and providing the basis for growth, profitability, and production. It also includes the inclusion of employee safety and health programs throughout the organization. The existence of a strategic plan for the scientific and practical strengthening of occupational health and safety is one of the country’s academic and industrial priorities. The purpose of this study is to present a strategic plan for developing the specialized field of occupational health and safety engineering in Iran.

The current study is a collaborative action research study that was conducted in 2021. The strategic planning committee consisted of 20 professors, experts, and doctoral students. Over the course of 14 weeks, they held regular weekly meetings, collected information from inside and outside the organization, analyzed the organization’s internal and external environment, and identified its strengths, weaknesses, opportunities, and threats. Based on this analysis, the committee determined the organization’s mission, perspective, values, and general and specific goals for 2021-2024. They also identified the necessary measures to achieve these goals and developed an operational plan to improve the performance of the specialized field of occupational health and safety.

Conducting this applied research led to the strategy of internal and external analysis of the specialized OHS field, determining the direction of the basic strategy, mission, perspective, values, and general goals. Finally, seven specific goals and 286 actions were determined to improve the performance of OHS. The SWOT analysis of OHS’s internal and external environment identified 27 strengths, seven weaknesses, 26 opportunities, and 12 threats. According to the results of the SWOT matrix, the strategic position of the OHS field is to implement preventive strategies and maintain existing conditions.

This plan aligns with the 4-year OHS plan. In developing the program, attention has been paid to the documents and policies of upstream organizations. The strategic position of occupational health and safety engineering is a prudent strategy. In this situation, strategies for maintaining existing conditions can be applied. Therefore, it is suggested to reduce the weaknesses of OHS as much as possible and increase its strategic capabilities by focusing on prudent strategies. From the second year of implementing the strategic plan, the OHS field can gradually focus on developing activities.

Air traffic control is a very complex process, including multiple human-machine interactions. Human mental workload plays an important role in this process. Nowadays, electroencephalography indexes are considered as new indicators in the field of assessment of mental workload. The purpose of the present study was to investigate the relationship between EEG theta power and mental workload in air traffic control simulation.

Fourteen air traffic controllers participated in this study. Controllers carried out two scenarios, including low and high workload, based on task load factors in an air traffic control simulator. Mental workload was assessed in these two scenarios by the NASA-TLX questionnaire. EEG signals were continuously recorded during air traffic control tasks. Afterward, absolute theta power was extracted from participants’ EEG using Fast Fourier Transform (FFT) by the MATLAB software and was compared with each other in terms of high and low workload.

The results showed a significant relationship in absolute theta power during low and high workload scenarios in all regions of the brain (p < 0.05). Absolute theta power increased primarily in the frontal region during the high workload scenario. Also, there was a significant increase in the relationship between work experience and absolute theta power at the F3 region during the high workload scenario (P=0.021, r=0.607).

Absolute theta power provides a good parameter to assess mental workload at different levels of air traffic control tasks. Therefore, it can be used as a tool for the design of human-machine complex systems.

Toluene, benzene, xylene, and ethylbenzene (BTEX) belong to the class of monocyclic aromatic hydrocarbons and are identified as toxic volatile compounds due to their harmful properties. The reliable biomarkers for occupational exposure to these toxic compounds are hippuric acid (HA), trans,trans-muconic acid (tt-MA), mandelic acid (MA), and methylhippuric acid (MHA), which correlate with toluene, benzene, ethylbenzene, and xylene, respectively.

A novel magnetized imine-linked covalent organic framework (Fe3O4@TFPA-Bd) was synthesized, marking its inaugural use as a sorbent in microextraction by packed sorbent (MEPS). The synthesis of Fe3O4@TFPA-Bd was executed in a straightforward and efficient manner, using Fe3O4 nanoparticles as the magnetic core and benzidine (Bd) and Tris (4-formyl phenyl) amine (TFPA) as the structural building blocks. This newly produced sorbent was tested for the microextraction of hippuric acid (HA), mandelic acid (MA), trans, trans-muconic acid (tt-MA), and m-methyl hippuric acid (m-MHA) from urine samples, which were then analyzed using high-performance liquid chromatography (HPLC). In order to optimize the extraction performance, parameters like sample volume, elution volume, extraction cycles, pH, and sample solution temperature were thoroughly adjusted. The synthesized adsorbent underwent thorough characterization via scanning and transmission electron microscopy (SEM and TEM), Fourier transforms infrared spectrometer (FTIR), and X-ray diffraction (XRD).

The developed method showcased promising attributes: low detection limits (0.02 µg/ml for tt-MA, S/N=3), low quantification limits (0.06 µg/ml for tt-MA, S/N=10), a solid linear range (0.5-320 µg/ml for MA, R > 0.99), and commendable intra- and inter-day precision (2.4%-4.3% and 3.1%-7.8%, respectively) for volatile organic compound (VOC) biomarkers. Furthermore, the method demonstrated recoveries in the 81-87.5% range for spiked samples, indicating its practicality and effectiveness.

The developed procedure was suitable for the determination of BTEX biomarkers from urine samples and can be an alternative to previous methods.

The aim of this study was to investigate the effect of particle size (mesh) on the sound absorption coefficient of the absorbers made from Arundo Donax reed and to determine the optimal mesh for sound absorption.

After crushing the reed stems in 10, 30, 20, 16, and 40 mesh sizes, they were washed with 5% NaOH. To make the samples 3 and 10 cm in diameter, 10% PVA was used as a binder, and the impedance of the two-channel tube was used according to ISO 10534-2 standard to determine the absorption coefficient. 22 samples of meshes 16 and 20 were made to achieve the optimal mesh based on the optimized RSM method, and the SAA index was used to compare the samples and determine the optimal mesh.

The highest absorption peak was related to meshes 16 and 20 at the frequency of 2500 Hz, which is 0.94 and 0.98 ,respectively. The effect of increasing the thickness and density on the absorption coefficient is evident. The results have shown the effect of increasing the thickness and density on the absorption coefficient in mesh 20 in such a way that by increasing the density from 150 to 250 and the thickness from 10 to 30 mm, the absorption coefficient has increased from 35 to 63.5%. The optimal sample was mesh 20 with a thickness of 30 and a density of 250 kg/m3, which had the highest average absorption (SAA=0.57). The greater distance between the real and imaginary parts of the impedance shows the reactivity of the sample. In mesh 16 this distance is greater, as a result, mesh 16 has more reactivity and correspondingly less absorption.

The role of particle mesh as one of the important and influencing parameters on absorption coefficient has been investigated in this study.

Prolonged sitting postures are among the risk factors for musculoskeletal disorders in occupational settings, leading to increased musculoskeletal discomfort in various body regions. This discomfort can negatively impact individuals’ health and impose high costs on society in terms of work absences, early disabilities, and reduced productivity. The purpose of this study is to investigate the effect of stretching exercises on the level of discomfort, muscle activity, and muscle fatigue in the neck and trunk region during prolonged sitting tasks.

This experimental study was conducted among 20 healthy male and female participants under two test conditions: control and intervention. In the control condition, participants performed cognitive tasks (watching videos, typing, text editing, and nback cognitive test) without any intervention. In the intervention condition, participants performed stretching exercises before each task. The Visual Analogue Scale was used to assess perceived discomfort. Also, muscle fatigue was evaluated using an electromyography (EMG) device and RMS and MPF measures.

Discomfort in hands and arms (p-value=0.04) and lower back (p-value=0.03) during video-watching was higher in the control condition than in the intervention. Regarding muscle activity, the activity of the right cervical erector spinae during the video-watching task was lower in the control condition than in the intervention. In the n-back cognitive test and text editing, the right lumbar erector spinae muscle activity was significantly higher in the control condition than in the stretching exercises intervention. Regarding the left cervical erector spinae, a significant difference was observed between fatigue in control and intervention conditions during the video-watching task. Also, right thoracic erector spinae fatigue in text editing was higher in the control condition than in the exercise intervention; however, for the n-back test, the level of fatigue was lower in the control condition compared to the intervention.

The perceived discomfort in seated computer tasks is generally lower in the exercise intervention compared to the control condition. The stretching exercises used in this study improved muscle activity and reduced fatigue in some of the trunk muscles, although the effects of the exercises depend on the type of task. Overall, muscle fatigue in two cognitive tasks, text editing and n-back, was more affected by stretching exercises than other tasks.

Toluene is significant pollutants in the air. Long-term exposure to toluene can lead to adverse effects.  Biofiltration is one of the air pollutant control methods. In this study, Pseudomonas putida was selected as a microorganism capable of hydrocarbon degradation and its ability to biodegrade toluene in a suspension growth reactor was also investigated.

Experiments were conducted in two days and in five hours. Each method consisted of three sample reactors (A, B, C) and one control reactor (D). In the first method, the amount of bacteria in the sample reactors is 0.5, 1 and 2 McFarland and the amount of toluene injection into the reactors is the same (0.5 microliters) and in the second method, the amount of toluene injection into the sample reactors is 0.5, 1 and 1.5 microliter and 1.5 microliter in the control reactor and the amount of bacteria in them was the same (1 McFarland).Toluene gas samples and carbon dioxide were periodically analyzed.

In the first method of toluene decomposition, there was a significant difference between the three reactors (p-value = 0.002). The results of the second method were also significantly different between the three reactors (p-value<0.001). The decomposition of toluene in two methods also had a significant difference (p-value = 0.232). The amount of CO2 production was significantly different in the second method (p-value=0.003) and the first method (p-value<0.001), but no significant difference was observed in the comparison of the two methods (p-value=0.15).

Increasing bacterial in suspension growth reactor resulted in increased toluene biodegradation in shorter time while increasing toluene in suspension growth reactor may not have an additive effect on the biodegradation process.

The COVID-19 pandemic caused many businesses to face problems and created job insecurity, leaving many workers and employees stressed about losing their jobs. Therefore, the current research aimed to analyze the impact of workplace safety management measures on the behavior of organizational citizens concerning the role of job insecurity and the perceived risk of COVID-19 among the employees of Mashhad Social Security Organization.

The current applied research is a descriptive survey. The research population is all 560 employees of the social security organization of Mashhad city. The sample size was estimated based on Morgan’s table using a convenience sampling method, with a total number of 225. The data collection instrument was Wu et al.’s (2022) standard questionnaire, used to check construct validity and confirmatory factor analysis. Cronbach’s alpha coefficient and composite reliability were used to measure reliability, and the results showed that the questionnaire was adequately valid and reliable. The data analysis also involved structural equation modeling conducted in Smart PLS.

The results showed that workplace safety management measures have an impact on organizational citizenship behavior and the perceived risk of COVID-19. Also, the perceived risk of COVID-19 has a positive effect on perceived job insecurity. Yet, the perceived risk of COVID-19 does not influence organizational citizenship behavior and does not mediate the relationship between workplace safety management measures and organizational citizenship behavior. Workplace safety management measures have an impact on perceived job insecurity, and job insecurity has an impact on organizational citizenship behavior.

In light of the present findings, it can be concluded that workplace safety management measures are among the most important programs and strategies of organizations to increase citizenship behaviors, support employees, and provide safe conditions in an organization.

Many industries have multiple factors harmful to health, leading to simultaneous exposure of these factors to each other. Noise is one of the most common physical parameters in the work environment. On the other hand, heat is also increasing due to various energy processes in industries. Therefore, this study was conducted with the aim of determining changes in physiological parameters and visual-auditory attention in acute exposure to heat and noise.

In this experimental study, 72 individuals (36 men and 36 women) aged between 23 and 33 years participated according to the inclusion criteria. In total, 12 different test modes were performed (3 temperature levels and 4 noise pressure levels). The test was conducted for each person in 4 steps during a specific day. The duration of exposure to each condition was half an hour, and a half-hour rest was given between each test condition. Saliva samples of each subject were collected before and immediately after exposure to noise and heat. Also, The Integrated Visual and Auditory (IVA) was recorded by the participants simultaneously.

The results of combined exposure to noise and heat on visual and auditory attention showed that only two modes of combined exposure, SPL95+WBGT34 and SPL95+WBGT29, caused a significant increase (P < 0.05) in mental workload and a significant decrease (P < 0.05) in visual and auditory attention. In addition, the results showed that independent exposure to noise at the levels of 85 and 95 dB and exposure to heat at higher temperature levels of 34 and 29 degrees Celsius cause a significant increase (P < 0.05) in salivary cortisol after exposure. The results of the effect of combined exposure to noise and heat on salivary cortisol showed that three experimental modes of combined exposure (SPL85+WBGT34, SPL95+WBGT29, and SPL95+WBGT34) caused a noticeable and significant (P<0.001) increase in salivary cortisol.

Indeed, salivary cortisol can be recommended as a physiological index to evaluate noise and heat exposure. It’s also noteworthy that salivary cortisol is more affected by noise and heat exposure than cognitive performance.

Several extraction techniques have been developed in recent years to determine the concentration of volatile metabolites in a biological sample. This study conducted with the aim of using the needle trap device- molecularly imprinted polymer (NTD-MIP) for the co-extraction of n-hexane and methyl ethyl ketone (MEK) in the urine matrix.

Characterization of MIP was investigated by fourier-transfer infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), and brunauer–emmett–teller (BET). The response surface methodology - central composite design (RSM-CCD) was used to optimize the extraction conditions of n-hexane and MEK with the input variables of absorption temperature, absorption time, salt percent, and stirring speed. Method validation was performed with determination of the precision, accuracy, the limit of detection (LOD), limit of quantification (LOQ), and dynamic linear range.

The optimum conditions were an extraction time of 60 min, an absorption temperature of 65 °C, 22% of salt, and a stirring speed of 250 rpm. The linear ranges of n-hexane and MEK were determined in ranges of 30-500 and 30-4000 µg/L, respectively. The intra-day and enter-day relative standard deviation were evaluated in the range of 3 to 10 and 1 to 7, respectively. The average recovery of n-hexane and MEK were estimated 99.3 ± 0.8 and 99 ± 0.9, respectively.

The HS-NTD method is suggested as a suitable method for determining very low amounts of MEK in urine along with n-hexane.

Nurses’ high workload may affect their ability to work, cause health problems, and reduce nurses’ quality of life. Considering the important role of nurses in society’s health, it is important to identify the factors affecting their physical and mental health. The current study investigates and correlates nurses’ workload, quality of life, workability, and contextual variables.

In this descriptive-analytical and cross-sectional study, 142 subjects from the ICU, CCU, emergency department, and other departments of Qazvin educational-therapeutic hospital participated. Data collection tools included a demographic information questionnaire, NASA-TLX (Task Load Index), Short Form Health Survey (SF-36), and work ability index (WAI). Data were analyzed with an independent t-test, Pearson’s correlation coefficient, and a one-way ANOVA test.

The mean and standard deviation of nurses’ age and work experience were 31.3±6.1 and 7.6±5.8, respectively. The mean and standard deviation of nurses’ workload score, quality of life, and workability were 80.4±13.4, 55.5±18.7, and 31.8±7.3, respectively. According to the results, nurses’ workload had a significant relationship with quality of life (P-value=0.001) and workability (P-value=0.000). Significant relationships were also observed between quality of life and workability (P-value=0.001). Quality of life had a significant negative correlation with age, work experience, and the number of nurses’ shifts per month (P-value<0.05). Nurses with higher education had lower workload and higher workability.

Nurses working in ICU and CCU units had a higher workload. Nurses with higher education levels had less workload and more ability to work. There was an inverse correlation between workload quality of life and nurses’ workability. It is possible to reduce nurses’ workload by reducing their tasks and working hours.

Compared to other hospital departments, emergency department (ED) nurses experience higher levels of occupational fatigue. However, despite the importance of fatigue in EDs, limited studies have investigated the issue. Therefore, the present study aimed to identify factors affecting ED nurses’ fatigue with a systemic approach and provide a comprehensive model of fatigue.

The present study was the first phase of a mixed-methods study with an exploratory sequential design that was conducted qualitatively. Data was collected using a semi-structured interview technique among ED nurses in TUMS hospitals in Tehran. The data was analyzed with a systematic approach and qualitative content analysis method. To check the credibility and trustworthiness of the study results, Goba and Lincoln criteria, including transferability, peer review, and member check, were used.

Extensive factors were identified in the four levels of nurses’ work system, including individual factors, work unit, organization, and extra-hospital factors that could facilitate or prevent nurse fatigue. Specifically, the categories that were mentioned the most by the nurses were aggression and conflict with visitors, ED workload, understaffing, crowding and noise, obligatory overtime, acknowledgement, visitor’s expectations, reporting (paperwork), and clients’ distrust of nurses. Finally, based on the qualitative results, a conceptual model of factors affecting occupational fatigue of ED nurses in Tehran was presented.

Traditionally, fatigue management programs in hospitals only consider issues related to work shifts and sleep hygiene. However, the results of the present study revealed other fatiguing factors in the work system of ED nurses. These findings can help health system decision makers and HFE experts in designing effective fatigue risk management systems in Iranian hospitals, especially in emergency departments.

Studies have demonstrated that teaching carries a substantial burden of health risks. Prevalent health issues among teachers include asthma, respiratory diseases, musculoskeletal problems, and mental disorders. These problems can be attributed to the specific attributes of their work environment. Consequently, this study aims to investigate the correlation between air quality within educational establishments and the overall health of teachers.

This systematic review aims to examine the impact of temperature, humidity, and ventilation rates within educational environments on teachers’ health status and thermal comfort. Relevant studies were searched for using the PubMed and Web of Science databases, employing keywords such as teacher, temperature, humidity, ventilation, school, classroom, health symptoms, and thermal comfort (2000-2022). The inclusion criterion was that articles examined teachers’ health and comfort with temperature, relative humidity, and ventilation of the educational place.

Out of the 103 articles found in the initial search, 13 articles were finally reviewed. Six studies investigated the voice abnormalities of teachers due to various factors (including temperature, relative humidity, and the ventilation rate of the educational place) and found that these abnormalities were affected by these factors. Two studies explored the relationship between the prevalence and exacerbation of respiratory symptoms and quality parameters of the indoor environment of educational places. Additionally, five studies investigated the relationship of air quality parameters of educational places with common non-specific symptoms among teachers.

Teachers frequently experience symptoms such as voice disorders, respiratory difficulties, allergies, and other nonspecific ailments, which may be associated with the quality parameters of the indoor environment in educational settings. These parameters include temperature, humidity, and ventilation rate. Consequently, controlling and regulating these parameters within the recommended values can help prevent the onset or exacerbation of these symptoms.