IRAN OCCUPATIONAL HEALTH JOURNAL
Year:2018 | Volume:14 | Issue:6 |Papers Count:18

Background and aims: Shift work and in particular night shift work is associated with many problems such as sleep deprivation, sleepiness, decreased cognitive performance, increased human errors, and fatigue; it is also one of the major contributors of increasing the likelihood of risk of accidents in the industry. Better matching between individuals’ circadian rhythm and night shift and higher work performance can be achieved via designing an appropriate work shift pattern. The aim of this study was to compare the effect of two different rotating night shifts on information processing and alertness.Methods: This cross-sectional study conducted among 60 employees of the petrochemical industry control rooms with two different shift pattern consists of 7 consecutive nights (or 7 N) and 4 nights (4N). To assess the cognitive performance, n-back test, continuous performance test and simple reaction time test were employed. For assessing alertness the Karolinska Sleepiness Scale (KSS) were used.Results: Results from the both schedules indicated that the accuracy and speed of working memory and reaction time were significantly reduced (p<0.001), while attentional errors and sleepiness increased (p<0.01) during the shift work. Consecutive night shifts had a significant impact on reaction time and commission errors (p>0.05).Conclusion: The main duty of control room operators (CROs) at a petrochemical plant is checking hazardous processes which require appropriate alertness and cognitive performance. As a result, planning for appropriate working hours and suitable number of consecutive night shifts in a rotating shift system is a contribution to improving CROs performance and alertness and enhancing the safety.

Background and aims: Spray tower is a cost effective and simple equipment for ammonia gas purification. However, its’ appropriate performance in the removal of ammonia gas is under question. In this study, the effect of nozzle number, concentration of input ammonia gas and scrubbing liquid pressure over the removal efficiency of spray tower was studied.Methods: In present study, a spray tower was used to remove ammonia from air at room temperature and barometric pressure of Tehran. Ammonia gas at average concentration of 24.1, 52 and 68 parts per million was injected into the tower. Water was applied at a volumetric flow rate of 5 liters per minute and at 9, 10 and 12 bar head as the scrubbing liquid. The air flow rate in 3737.8 liters per minute was adjusted by a variable speed fan.Scrubbing liquid was sprayed using 1, 2 and 3 nozzle settings with a 20 mm size. The collected data were analyzed using the SPSS software.Results: The highest removal efficiency of 88.38% and the lowest removal efficiency of 51.47% were obtained. Increasing the number of nozzles did not increase the removal efficiency significantly (p=0.06).Conclusion: Removal efficiency of spray tower decreased by increasing the input ammonia gas concentration. Increasing the number of nozzles mounted on the spray tower from 1 to 3 increased the removal efficiency. Increasing the scrubbing liquid pressure increased the removal efficiency of ammonia gas by spray tower. It is advisable to increase the size of the nozzle outlet and apply caustic scrubbing solution to get removal efficiencies of higher than 90%.

Background and aims: The hospital staff services due to their jobs are daily exposed with disinfectant and cleaning substances and the exposure with these materials will cause dermatitis. The aim of this study was to determine the affection risk to skin symptoms in hospital staff services due to continuous exposure to detergents and disinfectants.Methods: In this cross-sectional study 170 male and female staff services in both Educational hospitals of Yazd were evaluated. Using Nordic questionnaire about the frequency of skin symptoms including: skin redness, swelling, scaling and small blisters, scaly and itching on the hands, forearms, and between the fingers of the employees were collected and analyzed by SPSS v.16.Results: In this study the overall prevalence of hand dermatitis among the staff service was 36.8 percent. The most common symptom of skin dermatitis was scaling of the hands, forearms or fingers along with cracking (25.5 percent). Symptoms of redness and itching of the skin, hands, forearms or fingers with cracked skin were more in women than men.Symptoms of red skin and scaly hands, forearms or fingers and cracking of skin were more in individuals with less work experience.Conclusion: The results showed a strong correlation between exposure in the workplace and skin dermatitis among workers in the service. In order to reduce exposure to detergents and reducing the incidence of skin dermatitis symptoms, use of appropriate gloves and proper training required in their use is recommended.

Background and aims: Clutch pedal is one of the most important control systems of automobile. As a foot controller due to the location and mechanisms of action, in case of improper design pedal clutch can reduce driver fatigue, as well as the comfort and safety of the vehicle. In the present research, clutch comfort of some common models of vehicles in taxi routes in Tehran were investigated from the viewpoint of ergonomics.Methods: In this cross-sectional and practical study, 120 drivers of taxi routes in Tehran were selected by stratified random sampling. Both objective (pressure-release force, frequency and duration of clutching) and subjective (specialized questionnai res) were used in order to assess fatigue and clutch comfort. Regarding objective assessments, the pressure-release force was measured using piezoelectric pressure dynamometer, and frequency and duration of clutching was estimated by means of a micro-switch named Data Logger.Results: Significant differences were observed in percieved discomfort in all bady parts involved in clutching, after the working shift. The highest discomfort belonged to back (3.97) and Knee (3.86) while the lowest value wer for upper thigh (1.45) and upper leg (1.98). Furthermore, drivers of Peykan and Roa automobiles reported the highest discomfort. Regarding the force and frequency of clutching, the hghest value was belonged to Peykan.Conclusion: According the the results, long-term use of the clutch pedal in all studied models of automobiles causes significant discomfort after the working shift. It is suggested that automobiles in Tehran taxi routes replace with the automatic gear ones and the Paykan and Roa, which showed the reatest discomfort) with other models.

Background and aims: The aim of this present study was to examine the effectiveness of work- life conflict management model on life satisfaction and work engagement of male employees.Method: Population of this study was male employees of Parsian Bank in Tehran. In a pretest- posttest experimental research design with control group, a total of 24 male employees selected via simple sampling and accidently divided into experimental group (n=12) and control group (n=12). The experimental group was undergone six-session format of work- life conflict management program and the control group didn’t receive any training program. Data was collected using Satisfaction with Life Scale (SWLS) and work engagement scale (UWES) and then data were analyzed using descriptive statistics and covariance analysis (ANCOVA).Results: Findings showed significance difference between both experimental and control group in satisfaction of life and work engagement score (P<0.01).Conclusion: according to the finding of this study it can be concluded that when employees can manage Work-life conflict, stress caused by role ambiguity and role conflict significantly reduced and at the level of life satisfaction and work engagement is increased.

Background and aims: The impact of work-related accidents due to multiple psychological consequences, financial and material outcomes, is in the focus of industrial and organizational psychology, management and health and safety specialist’s attention. For this purpose, this study aimed to compare personality characteristics and attitude towards safety among injured and non- injured workers was conducted in a large industrial plant.Methods: This research is done with the method Causal-comparative and sample of 32 persons of injured and 30 persons non- injured that were selected randomly, and for data collection questionnaire of Personality Traits and questionnaire of safety attitudes were used, both questionnaires have satisfactory reliability and validity. Findings were analyzed by use of multivariable analysis of variances and t test for independent groups. Analyzing and comparing is done by SPSS software version 16.Results: Scores of injured workers in the personality characteristic components as neuroticism, extraversion, openness to experience, agreeableness, conscientiousness, and attitude towards safety for injured workers are respectively 2.58, 3.39, 3.21, 3.51, 3.91 and 3.71, and for non- injured workers 2.48, 3.52, 3.25, 3.55, 3.90, 3.92 respectively. Despite the existence of differences between injured and non- injured workers in the scores of neuroticism, extraversion, openness to experience, agreeableness and attitude towards safety, but the differences was not significant (p<0.05).Conclusion: According to existence of differences between scores of personality characteristic components and attitudes toward safety among injured and non- injured workers and lack of significant differences in research findings, it is likely that the one of most causes of many occupational accidents in the industry is insecure environment. Hence, attention to safe work environment should be the first priority for officials and industry executives.

Background and aims: Safety in companies related to oil and gas is very important. Hence, the purpose of current study is to assess safety culture using behavioural and environmental forms in staffs of South Pars Gas Company.Methods: Totally, 1000 participants were randomly selected for this descriptive study from different parts of South Pars Gas Company. After selection of participants, demographic data were collected from each participant and behavioural and environmental forms based on Geller model were completed for all individuals through interview.Results: Totally, one hundred persons with mean age of 30.33±4.59 years participated in this study. Findings from behavioural form showed that safety status is in an appropriate condition, although some safety items in this form should be paid more attention. Findings from environmental form showed that this company not have appropriate function in some items including education, first aids, equipment safety, chemical substances, pressured cylinders, lighting, sound, vibration, atmospheric condition and ergonomics. Therefore, an appropriate plan is necessary to promote safety culture for these items.Conclusion: This study showed a good condition for behavioural safety status of South Gas company staffs, but no appropriate condition was seen for environmental safety status.Therefore, this condition should be more attention by the company's managers.

Background and aims: One of the most important and preventable hazard related to Healthcare Workers (HCWs) are Needle Stick Injuries (NSI). Biologic outcomes of these injuries can be so hazardous and can cause to transmission of disease such as AIDS, Hepatitis B and C. The aim of this study was determination of occupational exposure to needle stick and its risk factors in one of Sabzevar’s hospital.Methods: This is a cross sectional study on HCWs that by the help of related questionnaire, rate and characteristics of exposure of healthcare personnel was determined. Sampling method was in form of consensus and finally collected data with the help of STATA software and using descriptive and chi-square test were analyzed.Results: Occupational exposure to needle stick among participated HCWs with at least one injury in 12 months before study was close to 32.99%. Among the different variables that might have influenced on the needle stick injuries only training, education level and work experience had significant relationship. (p=0.001, 0.009, 0.009). About organizational factors, the result showed there is a good guideline for reporting injuries and about 79% of employees said they are familiar with how to report.Conclusion: The study showed that occupational exposure to needle stick among HCWs has a high frequency in this hospital. This problem should also be controlled in according to hierarchy. It seemed educational intervention could be useful in decrease of needle stick injuries problems.

Background and aims: Iranian lifting guidelines are used as a risk assessment tool to prevent back pain in various industries. It is believed that the tools and methods used for the assessment should be simple and yet accurate. Given that this guideline adopted the American Conference of Governmental Hygienists (ACGIH) threshold limit values (TLVs) for lifting as allowable load limits and the accuracy of the allowable weight values has not been investigated. The objective of this study was to investigate the effect of trunk angle and anthropometric dimensions on the accuracy of the allowable weight limits.Methods: In this study, 25 workers who had experience in manual handling were asked to perform lifting tasks in accordance with the Iranian guidelines. The subjects’ anthropometric and trunk inclination angles were recorded using a triaxial accelerometer (inclinometer) for each task, and the compressive forces were estimated using 3DSSPP and then compared with NIOSH’s recommended limits (3400N).Results: The results showed that among 25 tasks, the mean trunk angle of 13 tasks was between 90 and 130 degrees. Statistically, considering a standard deviation above the determined mean, the average compressive forces estimated for 9 tasks were greater than NIOSH recommendation (3400).Conclusion: In most tasks, vertical height and horizontal distance of external loads from the body leads to awkward postures that can be the main reasons for increased compressive force. Lack of adaption in some anthropometric measurements would result in increased mechanical loads on the back. Therefore, it seems that the limit values for Iranian lifting guideline are not sufficiently accurate to assess the risk of back injuries and thus should be revised.

Background and aims: Thousands of people die in road crashes each year and several hundred thousands are disabled as a result of road traffic accidents. Counts of fatal accidents are caused by drivers who are not complying with their jobs. Studies indicated that small percentage of people are more likely to have accidents in a similar situation, whom named as accident-prone drivers. This study aims to determine the effects of personality and demographic characteristics on accident proneness of Iranian bus drivers.Methods: This cross-sectional study conducted in the winter of 2016, in order to identify the relationship between driver’s personality and demographic characteristics with accident proneness. To obtain demographic and personality characteristics, NEO questionnaires was used. All samples were selected through drivers of a transportation company with similar work schedule. In order to control environmental parameters all sample were collected during certain hours of the day with similar traffic and weather conditions, during 20 days.To investigate the relationship between parameters, spearman as a non-parametric statistical tests was used by SPSS version 19.Results: Statistical analysis result indicated that in terms of personality neuroticism, extraversion, desire for new experiences, agreeableness, 72%, 33%, 69%, 41% and 100% of drivers were placed between 12-24, respectively, and 27%, 66%, 30%, 58% of them were categorized in the intermediate range 24 to 48. Results indicated significant correlation between the number of driver’s errors and each of the five measured personality inventory (P<0.05).Conclusion: The number of driver’s errors and NEO questionnaire score correlation indicated that use of this questionnaire provide a great opportunity to identify accident-prone drivers, especially when historical data is not available.

Background and aims: Research show exposure to pesticides is occupationally common in agricultural task. Organophosphate (OP) compounds are diverse classes of pesticides with the most well-known applications as insecticides and, to a lesser extent, as herbicides in agriculture. Organophosphate poisoning (OPP) is a major problem worldwide, especially in developing countries, with millions of cases and hundreds of thousands of deaths occurring each year.Methods: A total of 34 patients of male farmers spraying 20 to 60 years that exposure to organophosphate insecticides in the South West region were selected and were divided into two groups.17 patients as controls were studied among people who were not farmers.Protective clothing was offered to a group of farmers to use them during spraying. While another group of farmers in their daily work without the use of protective clothing were studied in this way. After spraying operation a blood sample collected from the three groups and their plasma cholinesterase activity was evaluated by DGKC method.Results: After spraying, the mean plasma cholinesterase enzyme in the control group was 8516.3 and in without clothes was 13655.8. But in the group with clothes enzyme average was 11639.3.Conclusion: Organ phosphorus pesticide poisoning in our country is one of the main causes of poisoning among farmers. However, according to the results of research and assessment of exposure to organophosphate insecticides and affect the levels of cholinesterase enzyme indicated, it can be said that the use of appropriate personal protective equipment has essential role in reducing the level of damage to the enzyme cholinesterase.

Background and aims: The application of computer codes and numerical modeling in studies and industry is growing. When using computer codes, the accuracy of these encodings and modeling are big questions. Comparing the results of the software with experimental results is the best method of evaluating these programs. The objective of this study was to experimentally validate a software program developed for local exhaust ventilation design.Methods: In this experimental study, seven different local exhaust ventilation systems were designed and constructed. Velocity pressure, static pressure, total pressure and air velocity were measured at key points of each system. All measured values were compared with similar calculated values by computer software. One-sample T test and Bland Altman plot were used to compare the similar measured and computed parameters. SPSS version 19 was applied for statistical analysis.Results: The percentage difference of measured and calculated air velocities at all channels and hoods were ignorable with maximum amount of 0.5%. Difference between the measured and the calculated values of velocity pressure, static pressure and total pressure in the entire systems were less than 5 percent. Bland-Altman plot and one sample T test showed that the differences were in the range of 2SD and confirmed matching.The results revealed that the air velocities measured with Pitot tube are much more accurate than those measured by thermal anemometer with maximum difference of 14.7%.Conclusion: This study showed that the tested software has an acceptable accuracy with less tha ±5% of error. It also revealed that the application of Pitot tube is much more accurate that thermal anemometer.

Background and aims: Car accident reports shows that the main cause of accidents is driver error and unsafe behavior. Workload of the major factors affecting driver has a direct impact on the incidence of traffic accidents. This study aimed to evaluate aspects of mental work load of auditory-verbal secondary task was performed while driving.Methods: Twenty professional bus driver randomly selected and participated in this study.The bus driving simulator and the burden of driver activities (DALI) was used. Experiment was created from two blocks: the first block drivers are only driving activity carried out and the second block in addition to the driver, auditory-verbal secondary task also responded to.To compare the results of two blocks, independent t-test and to investigate the relationship between a brake reaction time and mental load analysis, Pearson correlation coefficient was used.Results: The results showed that secondary task all aspects of mental workload increases significantly. A brake reaction time and the number of collisions dramatically increased in terms of the secondary task. The relationship between mental workload and increase reaction time was seen braking and collision numbers.Conclusion: The results of this study suggest that secondary task during driving can cause to increase the brake reaction time and risk of accidents by increasing the drivers’ mental workload of drivers and interfering with driving activity. These results indicate that driving experience does not reduce the effect of secondary activity during driving.

Background and aims: Body anthropometric dimensions are among the factors affecting the maximum oxygen consumption. This study aimed to predict maximum oxygen consumption based on anthropometric dimensions in medical emergency students.Methods: This cross-sectional analytical study was conducted among 56 medical emergency students from Qazvin University of medical sciences. Initially, physical activity readiness Questionnaire (PAR-Q) was applied to ensure the full health of participants to inter the study. Maximum oxygen consumption measured using Gerkin treadmill test.Anthropometric dimensions were measured by tape measure, anthropometer and kolis.Obtain data was analyzed by Pearson product moment correlation and multiple linear regressions in SPSS 19 software.Results: The mean age of participants was 21.69 years. The mean of maximum oxygen consumption and mean of foot length estimated 4.17 L/min and 96.35 cm, respectively.There was significant correlation between the maximum oxygen with the anthropometric dimensions. Variables of dimensions of abdomen circumstance, foot length and leg circumstance predicted 63.7 percent of the maximum oxygen consumption.Conclusion: The results indicated that the anthropometric dimensions are the factors affecting the maximum oxygen consumption among medical emergency student. Thus, it is necessary to be paid attention to anthropometric dimension in selection of students and matching between person capabilities with energy.

Background and aims: Today job stress is one of the most important problems of staffs that has physical and mental impact on them and also reduces their efficiency; therefore, it can affect organizations’ productivity and economy. Besides, regarding offices around the world and their improvements in 20th century comparing to offices in Iran shows that we need to research and change Iranian official spaces design. The aim of this study was to analyze the role of natural lighting, window views and indoor plants on stress reduction of offices’ staffs.Methods: To achieve this end, psychophysics method was used. To evaluate stressful conditions, a researcher-made test based on Stroop Word-Color Test was used to collect data analyzed by using MATLAB. The examinees were teachers from all provinces in Iran.Results: The analysis showed that the reaction time is increased in stimulus showing lack of natural light, window view and indoor plants. Accordingly, the average reaction time in unpleasant images is significantly more than pleasant ones (p<0.1).Conclusion: Data analysis shows that the degree of stress is influenced by natural lighting, window view and indoor plants of workplace that can be improved by giving attention to these three factors in interior design to design a pleasant and dynamic workplace.