Review of literature on occupational exposure to the dusts in Iran over the past 14 years

Introduction: Nowadays, millions of people are exposed to the dusts in their workplaces. Occupational exposure to dusts is considered as one of the most common and serious occupational hazards to workers' health. The purpose of this literature review was to review the literature related to the occupational exposure to dusts in Iran published over the past 14 years. Material and Methods: In this review, published articles were obtained from Web of Science, PubMed, Google Scholar, Scopus, ScienceDirect, Islamic World Sciences Citation (ISC), Magiran, SID. Iran Medex, and Civilica search engine. The main keywords for search were Occupational Exposure, Lung, Dust, Total Dust, and Respirable Dust. The relevant articles published in Iran over the past 14 years were searched and extracted after checking their relevancy. All articles were classified based on the titles, years of publication, places of publication, type of industries, geographic distributions, sampling and analysis methods, fields of study, and the amounts of exposure. Results: Findings showed that in spite of increases in the rate of published literature in recent years and by considering geographical variation and the large number of dust generating firms and industries, a relatively small number of studies was conducted and published in this field. Majority of the studies in this field considered the levels of dust exposure and respiratory effects of dust exposures. In most studies the levels of occupational exposure to dusts (and crystalline silica dusts) were higher than the recommended limit values. Conclusion: Although an increasing number of studies can be seen in recent years on occupational exposure to dusts and their effect, by considering the presence of large and small size industries with dust generating pollution in Iran, the large number of exposed people, adverse-health effects, and the need for control measures, few studies have been published in this field and further works need to be done in this area

Respiratory effects of exposure to flour dust: A case study among workers of flour production factories in Arak

      Flour dust has been introduced as one of the effective factors in the prevalence of respiratory disorders among the workers of the flour production factories. The purpose of the present study is to examine the effects of this pollutant on the pulmonary functions and survey the prevalence of respiratory symptoms among workers of flour production factories in Arak, Iran.  Exposure to flour dust is used to classify subjects into exposed (38 male workers of production plant) or unexposed groups (37 male employee from administrative section). Exposure level to flour dust, the prevalence of respiratory symptoms and pulmonary function in two group were studied using air sampling (based on method NIOSH 0600), a researcher made questionnaire on respiratory symptoms and Spirometer, respectively. The results indicated that workers of the production plant are exposed to high concentration of flour, which causes a decrease in the ratio of FEV1 / FVC compared to the unexposed ones. Among study respiratory symptoms, subjects had reported significantly more sputum secretion than that in control group. Furthermore intervening parameters, including age, work experience, body mass index and smoking didn’t show a significant effect on the pulmonary function of the individuals. Exposure to flour dust concentration with higher than threshold level values causes a decrease in workers respiratory capacity. Therefore, it is recommended that the reduction of both exposure risk and the 8-hour time-weighted average concentration of flour dust should be considered.

Relationship between oral temperature and sleepiness among night workers in a hot industry

      Night work can have a significant impact on health, well-being, performance and occupational safety of workers. Night workers often complain about the sleep disorder characterized by excessive sleepiness.  The aim of the study was to determine the level of sleepiness among night workers and investigate its relationship with oral temperature in a hot industry. This cross-sectional study involved 80 night workers. Stanford Sleepiness Scale (SSS) has been used to measure the level of sleepiness. Oral temperature and SSS were recorded at different hours of night shift (23 pm to 4 am) for two consecutive nights. The analysis of results showed that there was a positive linear trend in the sleepiness scale (Pvalue<0.001) and an increasing trend in the oral temperature between 23pm and 1am. Then a decreasing trend has been observed after 1am for both of them (Pvalue <0.001).  Comparison of the results for two nights indicated that the mean sleepiness index in the second night is higher than the first (Pvalue <0.001), but the mean oral temperature in the second night was equal to that in the first night. Findings suggest a weak negative association between sleepiness and oral temperature. (r=-0.24, Pvalue =0.03). A substantial proportion of subjects were working while sleepy, especially at late night and early morning hours. The combination of heat stress and sleepiness can lead to impaired performance. The growing amount of sleepiness index indicates the high risk of sleep disorders and the other possible problems related health among night shift workers

Evaluation of the Combined Effects of Heat and Lighting on the Level of Attention and Reaction Time: Climate Chamber Experiments in Iran

Heat exposure and unsuitable lighting are two physical hazardous agents in many workplaces for which there are some evidences regarding their mental effects. The purpose of this study was to assess the combined effect of heat exposure and different lighting levels on the attention rate and reaction time in a climatic chamber. This study was conducted on 33 healthy students (17 M/16 F) with a mean (±SD) age of 22.1±2.3 years. The attention and reaction time test were done by continuous performance test and the RT meter, respectively, in different exposure conditions including the dry temperatures (22°C and 37°C) and lighting levels (200, 500, and 1500 lux). Findings demonstrated that increase in heat and lighting level caused a decrease in average attention percentage and correct responses and increase in commission error, omission error, and response time (P<0.05). The average of simple, diagnostic, two-color selective, and two-sound selective reaction times increased after combined exposure to heat and lighting (P<0.05). The results of this study indicated that, in job task which requires using cognitive functions like attention, vigilance, concentration, cautiousness, and reaction time, the work environment must be optimized in terms of heat and lighting level

The Relationship between exposure to manganese in welding fumes and incidence of migraine headache symptoms

Background: Welding generates complex metal aerosols, inhalation of which is linked to adverse health effects among welders. Exposure to manganese (Mn) fume in welding processes can have a harmful effect on welders&rsquo; health. Long-term, high-level exposure to Mn is associated with impaired central nervous system (CNS) function. The present study aims to investigate relationship between exposure to manganese in welding fumes and incidence of migraine headache symptoms. Methods: This cross-sectional analytic study was conducted in March 2017 in an Iron Smelting Industry. Forty welders were selected as the exposure group and thirty-five employees were selected from the administrative unit as the control group. Data related to symptoms of migraine headache were collected using with Ahvaz migraine questionnaire (AMQ). Air samples were collected on mixed cellulose ester membrane filters in personal air samplers and then analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES) (NIOSH Method 7300). Results: The average concentration of welder&rsquo;s exposure to manganese was 7.24&plusmn;2.91 mg/m3, which is very higher (37 times) than the occupational exposure limit (Threshold limit value-time-weighted average). There was no significant difference between the mean age and work experience of the two groups (P<0.05). Comparison of the mean of migraine headache symptoms in the two groups of welders and office workers also showed that the frequency of these symptoms among welders was significantly higher than those reported by administrative staff (P<0.05). The correlation between the frequency of symptoms of migraine headache and the concentration of manganese in the air of the welders&rsquo; respiratory area was statistically significant (P<0.05). Conclusion: Frequency of migraine headache symptoms was higher among welders compared to control group. Statistically the significant relationship was found between airborne Manganese concentration and occurrence of migraine headache; however, a conclusive conclusion is based on more comprehensive studies with larger sample size

Spatio-Temporal Evolution of the Thermo-Hygrometric Index (THI) during Cold Seasons: A Trend Analysis Study in Iran

Global warming can cause deep and extensive changes in the Earth’s climate and changes in the time and place of climatic phenomena. The present trend analysis study assesses cold stress using the thermo-hygrometric index (THI) in the two seasons of autumn and winter in outdoor environments in Iran. The data related to the average of the two variables of daily air temperature and relative humidity from 60 synoptic meteorological stations for a statistical period of 30 years were obtained from the Iranian Meteorological Organization. The THI index was calculated for autumn and winter, and the level of thermal discomfort was determined for each station. The Mann–Kendall statistical test with the help of Minitab ver17.1.0 software was also used to investigate the changes in air temperature, relative humidity and THI index. The THI for autumn increased in 68% of the stations, and this increasing trend is statistically significant in 51% of these stations. The THI for winter increased in 83% of the stations, and this increasing trend is statistically significant in 51% of these stations. In autumn, 53% of the stations were in the range of thermal discomfort, and in winter only 5% were in the range of thermal comfort. The decreasing trend in THI in some climatic types, along with the increasing trend in air temperature, can indicate the decrease in relative humidity in the monitored stations during the studied years. It is recommended to know the temporal and spatial distribution and the probability of occurrence of cold stress through the use of THI in order to adopt preventive measures and policies in the outdoors in Iran

بررسی حذف بخارات تولوئن با استفاده از جاذب چارچوب آلی- فلزی

Background and Aim: Toluene (methylbenzene) is a volatile organic compound (VOC) that, when chronically exposed to low concentration, can cause a variety of adverse health effects, including immunological and neurological disorders. In addition, the release of toluene in the atmosphere causes various environmental problems, including the reduction of stratospheric ozone, the production of photochemical smog, and the increase of the greenhouse effect. The purpose of this research was to remove toluene from the air flow using imidazolate zeolite framework (ZIF-8) in order to be used in air purification processes and to prevent and reduce the risk of exposure to this hazardous pollutant in occupational settings and environments. Methods: Zeolite imidazolate framework (ZIF-8) was synthesized in situ, and its structure was investigated using X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and BET testing. The absorption performance of toluene by ZIF-8 in the gas phase was studied using a dynamic adsorption system developed according to BS EN ISO 10121-1:2014 and previous studies. Results: The results of the structural tests showed that the synthesis of ZIF-8 was successful. Its specific area has also increased compared to several similar articles. The average toluene adsorption capacity of ZIF-8 at a temperature of 30.5 degrees Celsius, a relative humidity of 33%, and a flow rate of 300 ml/min, with a mass of 10 mg, was equal to 2828.91 mg/g. In addition, the initial removal efficiency is reported to be 88.67%. The breakthrough time for 100% of ZIF-8 was determined to be 21,660 seconds. The recovery rate after 6 cycles of ZIF-8 remained as high as 84.7%. Conclusion: ZIF-8 exhibits a high adsorption capacity for toluene in the gas phase, along with a high initial removal efficiency and breakdown time. Due to its effective ability to adsorb toluene, this MOF can be considered for use in air purification and purification processes. However, further studies are needed to fully evaluate its potential as an industrial adsorbent, taking into account relevant considerations. Please cite this article as: Mohammad-Gholikhan-Khalaj P, Farhang Dehghan S, Hasanzadeh M, Panahi D. The removal of toluene vapors using metal-organic framework adsorbent. Irtiqa Imini Pishgiri Masdumiyat. 2023;11(2):116-127. Doi:https://doi.org/ 10.22037/iipm.v11i1.43147سابقه و هدف: تولوئن (متیل بنزن) یک ترکیب آلی فرار (VOCs) است که مواجهه مزمن با غلظت‌های پایین آن ممکن است باعث طیف وسیعی از اثرات سوء سلامتی مانند اختلالات ایمونولوژیک و عصبی شود. علاوه بر این، انتشار تولوئن در اتمسفر باعث ایجاد مشکلات زیست‌محیطی مختلفی از جمله کاهش ازن استراتوسفر، تولید مه دود فتوشیمیایی و افزایش اثر گلخانه‌ای می‌شود. هدف از این تحقیق حذف تولوئن از جریان هوا با استفاده از چارچوب ایمیدازولات زئولیت (ZIF-8) به منظور کاربرد در فرایندهای پاکسازی هوا و پیشگیری و کاهش ریسک مواجهه با این آلاینده مخاطره‌آمیز محیط‌های شغلی و محیط‌زیست بود. روش کار: چارچوب ایمیدازولات زئولیتی (ZIF-8) به روش سنتز درجا ساخته شد و ساختار آن توسط آزمون‌های ساختاری (پراش اشعه X و طیف‌سنجی مادون‌قرمز تبدیل فوریه، میکروسکوپ الکترونی روبشی نشر میدانی و آزمون BET) بررسی گردید. عملکرد جذب تولوئن بر روی جاذب در فاز گاز با استفاده از یک سیستم جذب دینامیکی در مقیاس آزمایشگاهی مطابق روش استاندارد ایزو   BS EN ISO 10121-1:2014 و مطالعات پیشین مورد مطالعه قرار گرفت. یافته‌ها: نتایج آزمون‌های ساختاری نشان داد سنتز ماف موفقیت آمیز بوده است. مساحت ویژه آن نیز در مقایسه با تعدادی از مقالات مشابه بیشتر تعیین شد. ميانگين ظرفیت جذب تولوئن (سه بار تکرار آزمایش) ماف ZIF-8 در دمای 5/30 درجه سانتی گراد، رطوبت نسبی 33% و دبی 300 میلی‌لیتر بر دقیقه با جرم 10 میلی‌گرم برابر با 91/2828 میلی‌گرم در گرم بود. علاوه بر آن راندمان حذف اولیه ماف ZIF-8  برابر با  %67/88  بود. زمان شکست 100 درصدZIF-8   برابر 21660 ثانیه تعيين شد. ميزان بازیابی جاذب پس از 6 چرخه همچنان تا %7/84 گزارش شد. نتیجه‌گیری: ماف ZIF-8 داراي ظرفيت جذب بالایي براي تولوئن از فاز گازي است، ضمن آنكه راندمان حذف اولیه و زمان شکست بالایی نيز برخوردار است. به سبب عملکرد مناسب این ماف در جذب تولوئن،  مي‌تواند با انجام مطالعات تکمیلی و مد نظر قرار دادن ملاحظات مربوط به جاذب‌های صنعتی، در فرايندهاي تصفيه و پاکسازی هوا مورد توجه واقع شود. به این مقاله، به صورت زیر استناد کنید: Mohammad-Gholikhan-Khalaj P, Farhang Dehghan S, Hasanzadeh M, Panahi D. The removal of toluene vapors using metal-organic framework adsorbent. Irtiqa Imini Pishgiri Masdumiyat. 2023;11(2):116-127. Doi:https://doi.org/ 10.22037/iipm.v11i1.4314

Spatio-Temporal Evolution of the Thermo-Hygrometric Index (THI) during Cold Seasons: A Trend Analysis Study in Iran

Global warming can cause deep and extensive changes in the Earth&rsquo;s climate and changes in the time and place of climatic phenomena. The present trend analysis study assesses cold stress using the thermo-hygrometric index (THI) in the two seasons of autumn and winter in outdoor environments in Iran. The data related to the average of the two variables of daily air temperature and relative humidity from 60 synoptic meteorological stations for a statistical period of 30 years were obtained from the Iranian Meteorological Organization. The THI index was calculated for autumn and winter, and the level of thermal discomfort was determined for each station. The Mann&ndash;Kendall statistical test with the help of Minitab ver17.1.0 software was also used to investigate the changes in air temperature, relative humidity and THI index. The THI for autumn increased in 68% of the stations, and this increasing trend is statistically significant in 51% of these stations. The THI for winter increased in 83% of the stations, and this increasing trend is statistically significant in 51% of these stations. In autumn, 53% of the stations were in the range of thermal discomfort, and in winter only 5% were in the range of thermal comfort. The decreasing trend in THI in some climatic types, along with the increasing trend in air temperature, can indicate the decrease in relative humidity in the monitored stations during the studied years. It is recommended to know the temporal and spatial distribution and the probability of occurrence of cold stress through the use of THI in order to adopt preventive measures and policies in the outdoors in Iran

Evaluating Effects of Heat Stress on Cognitive Function among Workers in a Hot Industry

Background:Heat stress, as one of the most common occupational health problems, can impair operators' cognitive processes. The aim of this study was to evaluate the impact of thermal stress on cognitive function among workers in a hot industry. Methods: In this cross-sectional study conducted in Malibel Saipa Company in 2013, workers were assigned into two groups: one group were exposed to heat stress (n=35), working in casting unit and the other group working in machin-ing unit (n=35) with a normal air conditioning. Wet Bulb Globe Temperature was measured at three heights of ankle, abdomen, and head. In order to evalu-ate the effects of heat stress on attention and reaction time, Stroop tests 1, 2, and 3 were conducted before starting the work and during the work. Results: A significant positive correlation was observed between WBGT and test duration (P=0.01) and reaction time of Stroop test 3 (P=0.047), and be-tween number of errors in Stroop tests 1, 2, and 3, during the work (P= 0.001). Moreover, Stroop test 3 showed a significant higher score for both test dura-tion and reaction time of workers in case group. Conclusion: Results of the present study, conducted in a real work environment, confirmed the impairment of cognitive functions, including selective attention and reaction time, under heat stress conditions