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Introduction: Toluene is considered as a group of chemical contaminants, causing problems for people’s health. Due to the high rate of evaporation and rapid emission in the surrounding environment, it leads to the exposure of many employees and people at risk and, subsequently, its irreparable effects on their health in different jobs. Therefore, its removal is very important. In the present study, this contaminant was removed using the copper metal-organic framework (MOF) under different operating conditions. Material and Methods: In this study, the copper MOF was synthesized using the one-pot and in situ method. Physical and morphological properties of the adsorbent were investigated using BET, XRD, FTIR and SEM techniques. The efficiency of the adsorbent in removing toluene from the air stream under the dynamic adsorption system was investigated by examining the effect of the variables of adsorbent mass, pollutant concentration and humidity. Isotherm, thermodynamics and kinetics equations were used to evaluate the data. Results: The results of experiments determining the properties of the metal-organic framework showed the formation of pure Cu-BDC crystals with mean and particle size distribution of 1.95 nm. The specific surface area calculated by the BET method for the mentioned sample was 686 m2 g-1 and the total volume of structural pores was 0.335 g3 cm3. The presence of micropores increased the dynamic adsorption capacity of toluene. The findings follow the Langmuir isotherm model and the Pseudo-second order kinetic model. Based on the results of thermodynamic studies, entropy change (ΔS°) and enthalpy change (ΔH°) were equal to -0.44 kJ mol-1 K-1 and -15.67 kJ mol-1, respectively. Gibbs free energy change (ΔG°) was also calculated negatively, indicating that the adsorption process was spontaneous and exothermic. The regeneration of the adsorbent was 77% after three cycles. Conclusion: According to the results of this study, the microporous copper MOF can be used as a result of cheapness, high access, high adsorption capacity and appropriate regeneration rate in different operating conditions for adsorption of toluene.

Introduction: The respiratory system, one of the most important organs of the body, can be affected by adverse effects, disorders and consequences in the workplace. Spirometry is one of the most important screening and testing tools in the periodic medical examination of every employee. This study was aimed to evaluate the factors affecting the respiratory function of staff of Tehran University of Medical Sciences (TUMS). Material and Methods: This descriptive-analytical and cross-sectional study carried out on 300 employees of TUMS according on during the enrollment phase of the Tehran University of Medical Sciences employee’s cohort (TEC) study was in order to survey the parameters affecting pulmonary function. Demographic data were collected through a demographic questionnaire. Spirometry was used to evaluate respiratory function parameters and bioelectric impedance was used to analyze body composition. Data analysis was performed by SPSS software version 25. Two-sample t-test, one-way ANOVA, and Pearson correlation coefficient were used for statistical analysis. Multiple linear regression was used to determine the effect of independent variables on the parameters of pulmonary function. Results: It was found that 73.6% of the subjects had a normal lung pattern, 7% had an obstructive pattern, 14.7% had a threatening pattern and 4.7% had a mixed pattern. There was a significant negative correlation between FVC and FEV1 parameters and smoking (P-value

Introduction: The skin, can be exposed to harmful factors like ultraviolet radiation (UV). Exposure to this physical hazardous agent could be contributed to pigmentation, erythemas, early aging, skin cancer, and DNA damage. The aim of this study, therefore, was to fabricate the polyacrylonitrile (PAN) nanofibers with the UV protection property by the use of various concentrations of titanium dioxide (TiO2) nanoparticles. Material and Methods: The PAN nanofibers (10%wt) containing 0, 1, 5, 10 and 15% wt of TiO2 nanoparticles were produced using electrospinning method. The morphological propertis of nanofibers were studied by scanning electron microscopy (SEM) and the functional groups were investigated by Fourier transform infrared spectrophotometer (FTIR). The UV protection property of nanofibers was studied by measuring UV transmittance as well as calculating UV protection factor (UPF). Results: The results showed that the diameter and morphological characteristics of nanofibers are different at various concentrations of TiO2 and increasing the concentration of TiO2 has resulted to an increase in nanofibers diameter. The analysis of FTIR results showed that TiO2 nanoparticles have been successfully loaded on nanofibers for UV protection purposes. The findings clarified that nanofibers loaded with TiO2 could increase the UV protection property up to 15%. Conclusion: Totally, our findings show the successful fabrication of UV-protective nano webs using TiO2 nanoparticles. the new combination used in nano matcould protect employees from UV radiation.

Background: Human in hot environments are exposed to several risks and discomforts which seriously affect their physiological and mental workload. However, they are required to take frequent rest breaks to prevent heat strain when working in hot environments. The main objective of this study is to systematically summarize the literature about the effect of cooling vests on physiological and perceptual responses that might help research and practice in the future.Inclusion criteria: Studies in scientific journals and other databases, focusing on the effect of cooling vests on physiological and perceptual responses will be included.Methods: Three main databases such as PubMed, Scopus, and Web of Science will be searched to find relevant literature on type of cooling vest and effects using subject headings and appropriate MeSH terms. Inclusion and exclusion criteria will be used for screening. Two authors will participate in all of the search stages including preliminary search, screening, quality assessment, data extraction, and data synthesis. We will limit our search to articles published in a peer review journal between 2000 and 2019. The protocol has been written according to PRISMA-P checklist. Three main databases such as PubMed, Scopus, and Web of Science will be searched to find relevant literature on type of cooling vest and effects using subject headings and appropriate MeSH terms. Inclusion and exclusion criteria will be used for screening. Two authors will participate in all of the search stages including preliminary search, screening, quality assessment, data extraction, and data synthesis. We will limit our search to articles published in a peer review journal between 2000 and 2019. The protocol has been written according to PRISMA-P checklist.Objective: The aim of this systematic review is to investigate and compare the effect of different types of cooling vests on physiological and perceptual responses in order to choose the best one according to affecting factors.PROSPERO Registration Number: CRD42019140820

Background: Heat stress evaluation and timely notification, especially using meteorological data is an important issue attracted attention in recent years. Therefore, this study aimed at answering the following research questions: 1) can enthalpy as a common environmental parameter reported by meteorological agencies be applied accurately for evaluation of thermal condition of outdoor settings, and 2) if so, what is it’s the best criterion to detect areas in stress or stress-free situations, separately. Methods: Nine climatic regions were selected throughout Iran covering a wide variety of climatic conditions like those, which exist around the world. Three types of parameters including measured (ta, RH, Pa and WBGT), estimated (metabolic rate and cloth thermal insulation), and calculated parameters (enthalpy and effective WBGT) were recorded for 1452 different situations. Enthalpy as a new indicator in this research was compared to WBGT in selected regions. Results: Altogether, a good consistency was obtained between enthalpy and WBGT in selected regions (Kappa value: 0.815). Based on the good ROC curve obtained using MedCal software, the criterion of the values more than 74.24 for the new index was determined to explain heat stress situation for outdoor environments. Conclusions: Because of simplicity in measurement, applicability of the indicator for weather agencies, the consistency observed between enthalpy and a valid as well as accurate index (WBGT), sensor requirements which take only a few seconds to reach equilibrium and so on, enthalpy indicator can be introduced and applied as a good substitute for WBGT for outdoor settings.

BACKGROUND AND OBJECTIVE: Personal protective equipments (PPE) are common equipments for control of workers exposure to harmful agents in work environment. Regarding to the critical role of the filter collection efficiency under hazardous conditions such as exposure to carcinogen materials, this study was performed to determine the effect of different factors on efficiency of respirator filters in removing hexavalent chromium mist. METHODS: In this quasi-experimental study, homogenous chromium mist at different conditions (concentration 1.25 and 2.5 mg/m3, relative humidity 50 and 80% , and temperature 0-5 and 35-40 oC) passed through two types of respirator filters (MSA and Spasciani). All samples (n= 384) were collected, using NIOSH 7600 test method at upstream and downstream of respiratory filters, simultaneously and analyzed, using an atomic absorption spectrometer and inductively coupled plasma (ICP), respectively. FINDINGS: Although type of filter had significant effect on hexavalent chromium mist removal, the ANOVA test results indicated that the increase of chromium mist concentration and relative humidity resulted a significant decrease in removal efficacy 0.53% and 0.42%, respectively (p

Background: Cobalt is one of the most important constituent present in ceramic industries. Glazers are the relevant workers when they are producing blue colored ceramic, causing occupational exposure to such metal. Through this study, urinary cobalt was determined in glazers in a ceramic industry when they were producing blue-colored ceramic glazes. Methods: In this case-control study, spot urine samples were collected from 49 glazers at the start and end of work shifts (totally 98 samples) in 2011. Control group were well matched for age, height, and weight. A solid phase extraction system was used for separation and preconcentration of samples followed by analysis by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). All participants filled out a self administered questionnaire comprises questions about duration of exposure, work shift, use of mask, skin dermatitis, kind of job, ventilation system, overtime work, age, weight, and height. The lung function tests were performed on each control and cobalt exposed subjects. Analysis of covariance (ANCOVA) was used to evaluate the obtained results. Results: Urinary levels of cobalt were significantly higher in the glazers compared to the control group. There were significant differences at urinary concentration of cobalt at the start and end of the work shift in glazers. Spirometric parameters were significantly lower in the glazers compared to the control group. Among the variables used in questionnaire the significant variables were dermatitis skin, mask, ventilation, and overtime work. Conclusion: This study verified existence of cobalt in the urine glazers, showing lower amount than the ACGIH standard.

Background and aims: Coronaviruses are important pathogens in humans and animals. In late 2019, a new coronavirus was identified as the cause of a group of pneumonia cases in Wuhan, Hubei Province, China. The disease spread rapidly, resulting in epidemics in China and reports of sporadic cases worldwide. In February 2020, the World Health Organization (WHO) identified COVID-19, which stands for Coronavirus 2019. The virus that causes COVID-19 has been identified as the Coronavirus virus, Severe acute respiratory syndrome 2 (SARS-CoV-2), formerly known as 2019-nCoV. Coronavirus disease 2019 (COVID-19) is a name for the disease, and the virus that causes it is known SARS-CoV-2. The very rapid spread of the COVID-19 in China and in many other countries has caused fear among people across the world. The novel coronavirus outbreak declared a Public Health Emergency of International Concern on 30 January 2020. Due to the fact that one of the ways of transmitting the coronavirus is through respiration, one of the most important ways to prevent coronavirus is to use personal protective equipment, including masks, so the knowledge around the use of masks by the general public prevention COVID-19 disease transmission is advancing rapidly. Policymakers require guidance on how to use masks and how to use them for people in the community to combat the COVID-19 disease pandemic. In this article, the relevant literature to inform multiple areas include transmission characteristics of COVID-19 disease, filtering characteristics and efficacy of masks and estimated population impacts of widespread community mask use were synthesized. Methods: In this descriptive review study was examinesd all articles on mask wear and its effect on the prevention of transmission of pandemic diseases, including COVID-19 and influenza, which were published in Farsi and English. PubMed, Web of Science, Google Scholar, Scopus and Embase databases were used to search for articles, focusing on the use of masks and the prevention of COVID-19 disease, and combining appropriate keywords (Masks, SARS-CoV-2, COVID-19, Influenza, Epidemic, Prevention and Transmission) without restricting the type of study. Results: Corona virus size ranges from 80 to 160 nanometers, which can help in choosing the appropriate mask and respiratory protection. Anyone who comes in close contact (less than of two meters away) with a person with respiratory symptoms (such as sneezing, coughing, etc.) is at risk for exposure to potentially infectious respiratory particles. A main route of transmission of COVID-19 disease is likely via small respiratory droplets, and is known to be transmissible from presymptomatic and asymptomatic individuals that come out in talking, coughing or sneezing. The most common droplet size is at least 5 to 10 micrometers. SARS-CoV-2 has a high transmission potential and its transmission rate to individuals is about 2.4. Disease spread was reduced by restrict contacts of infected individuals via physical distancing, contact tracing with appropriate quarantine and reduce the transmission probability percent act by wearing masks in public. The evidence indicates that mask wearing reduces the transmissibility per contact by reducing transmission of infected droplets. Public mask wearing is most effective at stopping spread of the virus when compliance is high. Therefore, one of the most important ways to prevent the coronavirus is to use personal protective equipment, including masks. The standard masks recommended by reputable organizations are surgical masks and N95 masks. The use of cloth masks is recommended as a last resort, and it has been stated that these types of masks are not part of personal protective equipment. Especially in people who are part of the medical staff and do patient care work. Because of the ability of these masks to protect the person is unknown, and caution should be exercised when using these masks. Ideally, these masks should be used with a protective device that covers the entire front of the face (chin and underneath) and both sides of the face. The N95 mask (American standard; equivalent to FFP2 in Europe) is recommended as a mask for health care workers who perform clinical care for patients with COVID-19 disease. So that if these people use these masks well and according to the instructions, they will not have any problems during the epidemic. In this article, the use of surgical and clean masks by medical staff in medical centers to prevent Rhinovirus infection is recommended and similar studies show that fabric masks have less filtration to the rhinovirus. The results of the above study on the use or non-use of fabric masks in the community cannot be used to control the source of coronavirus, which is a seasonal coronavirus. Another point is that wearing a mask as a source control is largely a cessation of this process, as large droplets become smaller particles suspended in the air that can spread more into the air. Homemade masks have the ability to filter out the normal range of droplets, just as they are effective in blocking droplets and particles, meaning that these masks help keep the droplets from spreading in space. There is no RCT study to evaluate the effect of masks on social transmission during a coronary heart disease. While there is evidence of a flu outbreak, the current global epidemic is a unique challenge. According to a conservative assessment of COVID-19, the initial rate of proliferation is estimated at 2.4. If the mask is used and the efficiency of the mask is 50%, this amount will be reduced to 1.35.The spread of the disease. If the spread of the disease is completely stopped, the initial rate of proliferation will be less than one. As a result, the spread of the disease ends in the community. Wearing a mask may be critical to preventing a second wave of infection in the health care system - more research is needed. Conclusion: A review of the use of masks in this article showed that proper use of masks at the community level has a significant impact on reducing the rate of disease transmission among people in the community. Non-medical masks use substances that prevent the release of droplets of the required size. Non-medical masks are very effective in reducing the transmission of influenza. The results show that non-medical masks are effective in small trials in blocking coronavirus transmission and in areas and periods when the use of masks was required and widely used; the transmission of the disease has decreased in the community. People are usually infected in the early period after infection, which usually has few or no symptoms during this period. It is also suggested that the general use of cloth masks is more effective than other health strategies, distance and patient diagnosis strategies in reducing the rate of disease transmission. It is suggested that government officials and relevant organizations strongly encourage the use of masks by the public and crowded environments as a requirement to reduce disease transmission. To reduce the transmission of respiratory viral disease, the following interventions should be preferred, preferably in combination: - Frequent washing with or without side disinfectants - Create a retainer such as using gloves, clothing and a mask equipped with a filter - Identify suspicious individuals by isolating possible cases However, it has been warned that long-term routine administration of some of the evaluated measures may be contagious without the threat of disease. Health officials need to provide specific guidelines for the production, use and disinfection or reuse of facial masks and to review their distribution on a regular basis so that they do not become deficient. According to the precautionary principle, the positive effect of wearing a public mask is "scientifically acceptable but unclear." While researchers may logically disagree about the degree of reduction and flexibility of the transfer rate, it seems that the relatively low benefits due to the exponential distribution of the transfer process can be collectively profitable. Models show that wearing public masks is most effective in preventing the spread of the virus when acceptance is high. This is the situation we see with vaccines.Therefore, the use of masks should be done extensively with confidence based on this principle in society. All countries suggest that masking is a low-risk but highly potentially positive action, so that many countries with a high prevalence of the disease have been able to reduce mortality with the widespread use of masks. It is recommended that governments apply the requirements for the use of masks, and that organizations that provide public services, such as public transport providers or stores, apply the rules: "Without masks, no services are provided." These rules should be accompanied by measures to ensure that people have access to masks, possibly without problems in the mechanisms of distribution and storage of masks, and to focus on the benefits of public health. Health officials also need to provide specific guidelines for the production, use and disinfection or reuse of face masks, and review their distribution on a regular basis to avoid deficiencies. Also, clear and applicable guidelines can help increase public acceptance of the use of masks at the community level and reduce communities to the goal of ultimately stopping the spread of COVID-19.

A lab scale bioreactor was designed for treatment of waste gas containing benzene, toluene and xylene (BTX). Initial characterization of the bioreactor involved quantification of the oxygen transfer coefficient (kLa) as a function of some main operational variables. To evaluate and obtain optimal conditions in the 2.36 L bioreactor, the effect on oxygen transfer rate in several operational conditions including different proportions of organic phase (0, 5, 10, 20 and 30 %) in eleven agitation speeds (0 to 1000) and five aeration levels (1 to 5 L min–1) were tested. The results showed that the presence of silicone oil caused a reduction in the kLa of the aqueous phase for all the concentrations studied. Reduction of kLa due to the presence of silicone oil increased with augmentation of silicone oil fractions. The positive impact of agitation speed and gas flow on oxygen transfer was also observed in the presence of silicone oil, although their impact was somewhat reduced at higher silicone oil content. In addition, it was found that total power consumption declined with addition of different fractions of silicone oil to bioreactor aqueous phase. It was deduced that the most optimal silicone oil fraction and stirring rate are 10 % and 800 rpm respectively, from the viewpoint of oxygen transfer and total power consumption rate. Empirical correlations for the oxygen transfer rate in the bioreactor with the presence of different fractions of silicone oil revealed that the experimental kLa lay within the values predicted. Variations pattern in exponents of correlations showed that addition of silicone oil up to 10 % improves the superficial gas velocity that leads to enhanced kLa of oxygen and higher proportion of silicone oil, which may have negative effect.

Background: Nickel is an important constituents widely used in different industrial processes for production of various syn¬thetic materials. For evaluation of workers’ exposure to trace toxic metal of Ni (II), environmental and biological monitor¬ing are essential processes, in which, preparation of samples is one of the most time-consuming and error-prone as¬pects prior to analysis. "nMethods: To evaluate factors influencing quantitative analysis scheme of nickel, solid phase extraction using mini columns filled with XAD-2 resin was optimized with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sam¬ple volume (up to 500 ml), elution volume, amount of resins, and sample matrix interferences. Nickel ion was retained on solid sorbent and was eluted with followed by simple determination of analytes by using flame atomic absorption spectrome¬tery. "nResults: Obtained recoveries of metal ion were more than 92%. The amount of the analyte detected after simultaneous pre-concen¬tration was basically in agreement with the added amounts. The optimized procedure was also validated with three differ¬ent pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. The developed method promised to be applicable for evaluation of other metal ions present in different environ¬mental and occupational samples as suitable results were obtained for relative standard deviation (less than 10%). "nConclusion: This optimized method can be considered to be successful in simplifying sample preparation for trace residue analy¬sis of Ni in different matrices for evaluation of both occupational and environmental exposures.

Background and aims: The welderschr('39') health threat due to exposure to welding fume is an important issue, so effective exhaust of fumes are needful for to be assured from the workers safety in exposured to such proccess. In this study, was evaluated prototype operation of local exhaust ventilation on-gun in bench scale. Methods: duct velocity Average was determined by using traverse points method and calculated flow rate by hood using ACGIH standard method. Also capture velocity close in contaminant source (Arc Point) was measured using thermal anemometer. Then in order to determine total particles concentration and capture efficiency created by system, Was used NIOSH 7200 standard method. Results: the results show that, duct velocity average and created flow rate by evaluated system was obtained respectively 6296.1±92.50 fpm and 34.06±0/50 scfm. Also capture velocity in close the weld point was obtained 140 fpm. Sampling results shows averaged total particles concentration in off and on positions of system, respectively 75±7 mg/m3 and 16.7±4 mg/m3. As a result achieved containment efficiency 77% by this system. Conclusion: The local exhaust ventilation used in this study was a low cust prototype and according to acheived results, it lead to reduce total particles concentration (T.P) in breathing zone aproximately to 22%.

Background: The workers who are working in the open and warm environments are at risk of health effects of climate and heat changes. It is expected that the risk is increase with global warming. This study aimed to investigate the changes of Wet Bulb Globe Temperature (WBGT) index in the past and to predict their trend of future changes in Tehran, capital of Iran. Methods: The meteorological data recorded in Tehran, Iran during the statistical period between 1961 and 2009 were obtained from the Iran Meteorological Organization and based on them, WBGT index was calculated and processed using Man-Kendall correlation test. Results: The results of Man-Kendall correlation test showed that the trend of changes of annual mean WBGT during the statistical period under study (1961-2009) has been significantly increasing. In addition, the result of proposed predictive model estimated that an increase of about 1.55 degree in WBGT index will be seen over 40 years from 2009 to 2050 in Tehran. Conclusion: Climate change in Tehran has had an effect on person's exposure to heat stresses consistent with global warming.

A chromium electroplating bath with the ability to produce homogenous mist was used to evaluate parameters influencing hexavalent chromium (Cr+6) mist sampling methods. The results of 48 Cr+6mist samples collected using the U.S. National Institute for Occupational Safety and Health method 7600showed that Cr+6concentration was higher: (1) For sampling by closed-face filter cassettes than for sampling by open-face filter cassettes (P

Background: Chromium exposure occurs in various industries such as ceramics industry. The main disadvantage of chromium is high toxicity when absorbed by the body. This study aimed to determine and compare urinary chromium values in the pre- and post-shift of ceramic glazers and the control group; investigate urinary chromium value according to the study variables; compare pulmonary function tests between ceramic glazers vs. the control group. Study design: A cross-sectional study. Methods: This study was carried out in Yazd City, central Iran on 49 glazers and 55 office workers in the same workplace as the control group. The urine samples were collected at both start and end of the work shift, and the control group was examined only once. Preparation of samples were conducted by Solid Phase Extraction (SPE). The analyses were performed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). All the participants filled out a self-administered questionnaire comprising of questions about smoking habits, work shift, skin dermatitis, job title, using mask, ventilation system, duration of exposure, overtime working, age, weight, and height. The lung function tests were performed on study groups. Results: The concentration of chromium after the glazer's shift was 2.73 times higher than the Biological Exposure Index (BEI) recommended by the occupational and environmental health center of Iran. Lung function tests were significantly lower in the glazers compared with the control group (P=0.001). Conclusions: Skin dermatitis and overtime working are the main determinants of high chromium level in glazers.

Background and aims: Cadmium is a common industrial and environmental contaminant causing adverse health effects on respiratory system and kidney. This has been classified as a human carcinogen. Biological monitoring of cadmium and its measurement in urine, hair, and nail samples can be considered as an evaluation of the internal dose. Because of trace concentration of analytes in biological samples and matrix interferences, the preparation of such complicated samples is necessary prior to analysis. This study deals with the optimization of parameters affecting solid phase extraction (SPE) procedure for the trace analysis of cadmium in workers’ hair and nail in city of Zanjan. Methods: Solid phase extraction using XAD-4 resin was optimized with regard to effective factors. The optimized procedure was validated based on the “within-day” and “day-to-day” reproducibility experiments and suitable accuracy and precision were achieved. The optimized method was used for pre-treatment of hair and nail samples. Results: Using the optimized method, the recoveries of the cadmium ion were more than 92%. A good reproducibility and repeatability was obtained for optimized method under the existing conditions. The concentrations of cadmium in hair and nail samples were 98.25 and 186.82 μg/g, respectively. Based on the results, the cadmium content of samples was more than recommended maximum level (10 μg/g). Conclusion: Solid phase extraction procedure using XAD-4 resin can be considered as a successful method to simplify the sample preparation for trace residue analysis. The findings indicated that, the developed method can be applicable for biological monitoring and for determination of analytes in different matrices like hair and nail to evaluate the occupational exposures.