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The prevalence of non-specific symptoms resulting of the increasing use of nanomaterials indicates a threat to human health that has led to the attention and expansion of risk assessment methods.

Thermal stress has a direct effect on various types of DNA damage, which depends on the stage of the cell cycle when the cell is exposed to different climate conditions. A literature review was conducted to systematically investigate and assess the overall effect of heat stress and DNA damage following heat exposure. In this study, electronic databases including PubMed, Scopus, and Web of Science were searched to find relevant literature on DNA damage in different ambient temperatures. Outcomes included (1) measurement of DNA damage in heat exposure, (2) three different quantification methods (comet assay, 8-hydroxy-2-deoxyguanosine (8-OHdG), and γ-H2AX), and (3) protocols used for moderate (31) and high temperatures (42). The evidence shows that long exposure and very high temperature can induce an increase in DNA damage through aggregate in natural proteins, ROS generation, cell death, and reproductive damage in hot-humid and hot-dry climate conditions. A substantial increase in DNA damage occurs following acute heat stress exposure, especially in tropical and subtropical climate conditions. The results of this systematic literature review showed a positive association between thermal stress exposure and inhibition of repair of DNA damage.

As main air pollutants, volatile organic compounds (VOCs) must be paid special attention. In this study, the removal efficiency of xylene from the air was investigated by nano-activated carbons (NACs) as an efficient adsorbent and compared to commercial activated carbons (ACs). In the chamber, the xylene vapor in pure air was generated, stored in the airbag (5 Li), and moved to adsorbents. Then, the xylene vapor was absorbed on the NAC/AC adsorbents and desorbed from it by a heat accessory. The efficiency of xylene removal with NACs and ACs was investigated in the dynamic and static systems based on 100-700 mg L-1 of xylene, flow rates of 100 ml min-1, and 100 mg of adsorbent at a humidity of 32% (25°C). Xylene concentrations were determined by gas chromatography equipped with a flame ionization detector (GC-FID). In the batch system, the maximum absorption capacity for NACs and ACs was obtained at 205.2 mg g-1 and 116.8 mg g-1, respectively. The mean adsorption efficiency for NACs and ACs adsorbents was obtained at 98.5% and 76.55%, respectively. The RSD% for NACs ranged between 1.1-2.5% in optimized conditions. The characterizations of the NACs adsorbent showed that the particle-size range was between 35-100 nm.

Acrylonitrile is a potential carcinogen for humans, and exposure to this substance can cause adverse effects for workers. This study aimed to carcinogenic and health risk assessment of acrylonitrile vapor exposure in exposed personnel of a petrochemical complex. This crosssectional study was performed in 2019 in a petrochemical complex. In this study, to sample and determine acrylonitrile's respiratory exposure, the method provided by the National Institute of Occupational Safety and Health (NIOSH 1601) was used, and a total of 45 inhaled air samples were sampled from men workers, aged 39.43 ± 9.37 years. All subjects' mean exposure to acrylonitrile vapors was 71.1 ± 122.8 μg/m

Background: Noise is one of these factors and it is considered as a concern through the world. The purpose of this study is to provide information about the rate of noise-induced hearing loss (NIHL) among workers in one of the cement. Methods: 283 workers were randomly selected from different production units in a cement factory. Equivalent Sound Level (Leq) was measured by using a Casella CEL-320 ‎ dosimeter and Sound Pressure Level (SPL) was measured by using a TES-1358 sound level meter (SLM) (sn: 090717269), with high accuracy. Audiometric tests were conducted by using an AVA C88 audiometer. Collected data were analyzed by using SPSS.16 software and statistical tests. Results: The mean Hearing threshold limit (HTLs) ‎ at frequencies (3 and 4 KHZ) in the study group is significantly higher than the control group (P

The present study investigated the relationship between occupational exposure to noise and whole-body vibration (WBV) with the levels of sex hormones in an automobile parts manufacturing plant. The level of workers’ exposure ( n = 162) to each of the mentioned stressors was measured through standard methods, and the time-weighted average of exposure was calculated for each person. In order to determine serum sex hormones (free testosterone, luteinizing hormone, and follicle-stimulating hormone), blood samples were taken from all participants after 8–10 h of fasting between 7 and 9 am and then the blood samples were analyzed by an enzyme-linked immunosorbent assay method. In general, regarding testosterone as the main male sex hormone, only 49% of the participants were in the normal range. In a total of three sections, the lowest mean testosterone levels were observed in the third exposure group (WBV > 1.93 m/s2; noise >92.69 dB) of the studied stressor; however, only the difference in testosterone levels between the three different groups of exposure to noise was statistically significant ( p = 0.001). The relationship between demographic variables and levels of noise and WBV exposure with sex hormones was not linear and only the relationship between noise exposure and testosterone levels was statistically significant ( R = −0.201, p = 0.013). According to the results of logistic regression, the WBV had the greatest effect on testosterone levels. However, according to the results of the correlation test, only the relationship between noise exposure and testosterone levels was statistically significant.

The aim of the present study is to fabricate neat nanofibers and hybrid ones containing metal-organic frameworks (MOF) and assess and compare their performance to remove of bioaerosols from air stream. Moreover, the antibacterial properties of neat and hybrid nanofibers have been investigated. According to the findings, both neat and hybrid media had better mean microorganism collection efficiency at face velocity of 0.1 m/s compared to 0.3 m/s (p>0.05). The studied media were better able to remove Staphylococcus aureus than Escherichia (p>0.05). Increased temperature had no significant effect on the filtration efficiency (p>0.05). Increased relative humidity lead to significant reduction in the removal efficiency of Escherichia for hybrid media (p

The authors would like to thank Tehran University of Medical Sciences and Iran National Science Foundation (INSF) , for supporting this project. This study was supported by Tehran University of Medical Sciences under Ph.D. thesis scheme (Number: 9421138001) and the INSF. The funding body played no role in the design of the study, collection and analysis of data, interpreting results or writing the manuscript or decision to submit the manuscript for publication. The content of this publication is only the responsibility of the authors., Background: A hand-held portable direct-reading monitor, including photoionization detector (PID) is renowned for its good sensitivity, considerable dynamic range, and nondestructive vapor detection ability in comparison to the tardy response of the PID in gas chromatography (GC), which its application has been restricted. In this study, the performance of a PID system (MultiRAE Lite) was evaluated as a replacement of GC in the measurement of toluene in a dynamic adsorption system. Methods: The test was done at different relative humidity levels (30%, 50%, and 80%), temperatures (21, 30, 40°C), and toluene concentrations (20, 100, 200, and 400 ppm). Results: The PID achieved 48% of all measurements meeting the comparison criterion. The results showed that the performance of the PID could be altered by the variables. The best performance of the PID was at temperature of 21°C, the relative humidity of 50%, and concentration of 200 ppm with the percentage of readings achieving the criterion of comparison to 58%, 54%, and 52%, respectively. The averages of the PID readings (mean ± SD at 200 ppm= 207.9 ± 8.7) were higher than the reference method measurements averages (mean ± SD at 200 ppm= 203.5 ± 5.8). The regression analysis of the toluene results from the PID and the reference method results indicated that the measurements were significantly correlated (r2 = 0.93). Conclusion: According to the results, the device response is linear. Therefore, the findings are acceptable in adsorption studies. In this way, the measurement of the sample concentration should be performed using the same instrument before and after the reactor in order to calculate the adsorption efficiency., Tehran University of Medical Sciences, Iran National Science Foundation (INSF), Tehran University of Medical Sciences 9421138001

The aim of the present study was biodegradation of toluene using a two-phase low-pressure bioscrubber with silicon oil as organic phase. The bioscrubber designed in this study consisted of two part...

The presence of hazardous agents in workplaces has raised concerns regarding their possible impacts on male reproductive system. The present study investigated the individual and combined effects of exposure to heat stress and electromagnetic fields with low-frequency characteristics on the levels of sex hormones in two foundry sections (Aluminum and Cast Iron) of an automobile parts manufacturing plant. The level of workers' exposure (n = 110) to each of the mentioned stressors, was measured through standard methods and for each person and the time-weighted average (TWA) of exposure was calculated. The participants of each sections were classified into separate exposure groups based on the 33rd and 66th percentile of the level of to heat stress and electromagnetic fields exposure. In order to determine serum sex hormones, blood samples were taken from all participants between 7-9 am and then the blood samples were analyzed by ELISA method. In total of two sections, the lowest mean testosterone levels was observed in the third exposure group of the electromagnetic fields (magnetic field>1.40 μT; electric field >0.42 V/m), however, the mean difference in testosterone levels between the three different groups of exposure wasn't statistically significant (P > 0.05). According to the results of Logistic Regression, the electric field had the greatest effect on testosterone levels as the main male hormone. Drawing a definitive conclusion regarding the effects of each harmful physical hazards is difficult due to the existence of psychological stressors and other environmental stressors such as chemical pollution, ergonomic hazards and other physical stressors.

Toluene is a single-ring aromatic, which is widely used in various industrial processes. Regarding to harmful effects to human, the aim of this study was removal of toluene from the airflow using industrial-scale low-pressure two-phase bioscrubber with cutting oil. The design of the bioscrubber of the present study consisted of two parts of the adsorption column and a. Also, cutting oil was added at concentrations of 5%, 7.5% and 10% as organic phases and tested. The results show that after 72 hours with increasing organic phase concentration, toluene concentration was further decomposed compared to the control sample. The results showed that the use of 5% concentration of cutting oil increased the efficiency from 22% in the case of no organic phase to 55% in the case of using 5% of cutting oil. At a concentration of 7.5%, the lowest efficiency was 38% and the highest was 63%. Also, the minimum and maximum removal capacity are 17 and 269 g/m3.h, respectively. Efficiency at a concentration level of 5% of cutting oil as an organic phase is better than a concentration of 7.5%. In this study, for the first time in Iran, cutting oil was used as an organic phase, which showed that cutting oil in concentrations less than 10% had no effect on the growth of microorganisms. The results showed that shear oil and silicone oil increased the adsorption of volatile organic compounds in bioscrubber.

1,3-Butadiene is classified as carcinogenic to humans by inhalation. This study aimed to assess cancer and non-cancer risk following occupational exposure to 1,3-butadiene. This cross-sectional study was conducted in a petrochemical plant producing acrylonitrile butadiene styrene copolymer in Iran. Occupational exposure to 1,3-butadiene was measured according to the National Institute for Occupational Safety and Health 1024 method. Cancer and non-cancer risk assessment were performed according to the United States Environmental Protection Agency method. The average occupational exposure to 1,3-butadiene during work shifts among all participants was 560.82 ± 811.36 µg m−3. The average lifetime cancer risk (LCR) in the present study was 2.71 × 10−3; 82.2% of all exposed workers were within the definite carcinogenic risk level. Also, the mean non-cancer risk (hazard quotient (HQ)) among all participants was 10.82 ± 14.76. The highest LCR and HQ were observed in the safety and fire-fighting station workers with values of 7.75 × 10−3 and 36.57, respectively. The findings revealed that values of carcinogenic and noncarcinogenic risk in the majority of participants were within the definitive and unacceptable risk levels. Therefore, corrective measures are necessary to protect these workers from non-cancer and cancer risks from 1,3-butadiene exposure.

The exposure to ultraviolet radiation (UVR) can contribute to pigmentation, erythemas, early aging, and skin cancer. The purpose of this paper was to fabricate the polyacrylonitrile (PAN) nanofiber...

Commercial activated carbon of coconut shell has been oxidized with nitric acid, and their oxygen surface complexes have been characterized by classical titration following Boehm’s method and by FT...

Humans in hot environments are exposed to health risks and thermal discomfort which seriously affect their physical, physiological and mental workload. This study aimed to assess the effects of using cooling vests (CVs) on physiological and perceptual responses in the workplace. Three main databases were searched using subject headings and appropriate Mesh terms. The article has been written according to the preferred reporting items for systematic reviews checklist. A total of 23,837 studies were identified for screening and 63 studies were eligible for data extraction. A statistically significant difference was observed in body temperature among hybrid cooling garments (HBCGs), phase-change materials (PCMs) and air-cooled garments (ACGs) at 31.56-37 °C (60% relative humidity), evaporative cooling garments at 25.8-28.1 °C and liquid cooling garments at 35 °C (49% relative humidity) compared to without CVs (

Some occupational skin exposures lead to the formation of reactive oxygen species (ROS). The occupational exposure of workers to ROS has been found to be associated with an increased risk of developing skin injuries; therefore, it is essential to protect skin against ROS formation. Recently, some studies have been conducted on introducing better alternatives for skin protection. Nanofibers are good candidates for this purpose. The current study was carried out to assess vitamin E-loaded hybrid Poly(ε-caprolactone) (PCL)/gelatin (Gt) nanofibres mats as protective layers of skin exposed to occupational exposures. Vitamin E (VE) was successfully incorporated into PCL/Gt nanofibers while they were formed by electrospinning method. Nanofibers mats were characterized using scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). Their degradation behavior, in vitro release, biocompatibility, and antioxidant activity were studied. The diameters of the PCL/Gt/VE nanofibers decreased with the addition of vitamin E. The degradation rate of nanofibers was equal to 42.98 and 50.69% during 7 and 14 days, respectively. Nanofibers containing vitamin E showed an initial burst followed by a sustained release. The PCL/Gt/VE nanofibers exhibited good free radical scavenging activities despite being exposed to a high electrical potential during electrospinning. PCL/Gt/VE nanofibers supported a higher level of viability compared to PCL/Gt ones and significantly assisted human skin cells against tert-Butyl hydroperoxide (t-BHP) induced oxidative stress. Overall, PCL/Gt/VE nanofibers can potentially be used to protect skin against oxidative stress as a novel approach for worker’s healthcare.

BACKGROUND: This ecological study aims to model the trend of changes in exposure of outdoor workers to heat stress in outdoors in the coming decades with the use of the Wet-Bulb Globe Temperature (WBGT), Hadley Coupled Atmosphere- Ocean General Circulation Model, version 3 (HADCM3), and Long Ashton Research Station Weather Generator (LARS-WG) in Tehran, Iran, considering the climate change and the global warming. METHODS: The hourly values of environmental parameters including minimum and maximum air temperature, relative humidity, precipitation and radiation related to Prakash , Shahriar and Damavand cities were obtained from the Meteorological Organization of Iran. These data were recorded during 1965 to 2015. The climate modeling was done for 2011–2030, 2046–2065, and 2080–2099. RESULTS: The minimum and maximum air temperatures in the different months of the year in the three studied cities show an increasing trend. Our finding shows that the WBGT will be increased by 2099. In Pakdasht, this index will be close to the danger zone in the coming years, especially in 2080–2099. CONCLUSIONS: All the results obtained indicate an increase in risk of heat stress in outdoor workplaces, given the global warming.

This study aimed to evaluate pulmonary function among workers exposed to 1,3-butadiene and was carried out in a petrochemical industry in Iran. The study participants consisted of fifty male workers with current respiratory exposure to 1,3-butadiene and fifty non-exposed workers as the control group. Exposure to 1,3-butadiene was measured according to the NIOSH 1024 method. Respiratory symptom histories were collected through the American Thoracic Society respiratory symptom questionnaire. Lung functions were evaluated using spirometry method. The results showed that exposed participants had significantly higher prevalence rates of all respiratory symptoms compared to the control group. Statistical tests demonstrated a significant difference between pulmonary function tests of exposed and non-exposed personnel. Ultimately, the results of the present study indicate that respiratory exposure to 1,3-butadiene can lead to negative effects on pulmonary functions.

Background: We aimed to investigate the efficiency of neat polyacrylonitrile (PAN) nanofibers and photocatalytic PAN/TiO2 nanofibers for removal of airborne microorganisms. Methods: Nanofibers were fabricated from 16 wt% of PAN dissolved in dimethyl formamide through the electrospinning technique. The efficiency of media for removal of Staphylococcus epidermidis and Bacillus subtilis was investigated at different conditions such as face velocity, relative humidity, air temperature and UVC radiation intensity. as face velocity (0.1 and 0.3 m/s), relative humidity (35±5% and 60±5%), air temperature (22±3 °C and 30±3 °C) and the UVC radiation intensity (dark, 1±0.09 mW/cm2 and 1.8±0.07 mW/cm2) using air sampling from upstream and downstream of media by cascade impactor containing blood agar culture medium. Results: The mean diameter of electrospun fibers and coefficient of variation were 194 nm and 15%, respectively. The amount of immobilized TiO2 on the filter was 620±6.56 mg/m2. Photocatalytic nanofiber filter media presented the best performance for removal of airborne B. subtilis at 60±5% relative humidity, 0.1 m/s face velocity, air temperature 22 °C, and 1.8 ± 0.07 mW/cm2 UVC radiation. Conclusion: The filtration efficiency of photocatalytic media was significantly higher than neat ones. Lower efficiency of media was found in the higher air velocity for all bioaerosols. High UVC radiation intensity increased filtration efficiency. Moreover, the increase in air temperature and relative humidity (except for TiO2-coated media under UVC radiation) did not significantly affect the filtration efficiency of all media.

The Wet Bulb Globe Temperature (WBGT) is still widely applied as a preliminary tool for evaluating heat stress. This index faces some limitations not considered yet. This systematic review was conducted aiming at highlighting some limitations for the development of the WBGT index. The present study was organized using more extensive databases, including PubMed, Google Scholar, Scientific Information Databases (SID), Elsevier, Web of Science, Scopus, Irandoc, Magiran, and Iran Medex. The used search terms were WBGT index, Heat stress, Thermal Stress, Heat strain, Wet Bulb Globe Temperature, Hot Condition, Occupational Health, and Occupational Exposure indices. In this study, 69 articles from the years 1950 to December 2021 were assessed. The WBGT index, despite having some advantages, suffers limitations that should be considered for a more accurate estimate of thermal stress. This study was pointed to the new limitations, including the value of WBGT is not clear for persons whose working in a seated posture. The additional problem with the use of this index was that it was used for adapted people who have consumed enough water and salt, while neither water nor salt is always readily available in most hot working environments. Therefore, using this index will cause an error. Also, in heterogeneous environments, if the heat source is near the head or legs, a coefficient will not be applied to these regions. The results of the study demonstrated that, because of the limitations of the WBGT index, it is recommended that this index be used along with other indicators and physiological parameters to assess heat stress until more extensive studies would be conducted in an attempt to improve and remove its limitations.

Titanium dioxide (nano-TiO

Background: The present study aimed to assess the effects of the supplementation consumption of vitamin E and Omega 3 fatty acid on the oxidative stress parameters among workers exposed to high levels of noise in an automobile parts manufacturing plant. Moreover, the effects of the exposure to noise on SOD, total oxidative stress (TAC) and MDA will be investigated. Methods: The participants were deployed into 4 groups (vitamin E (100 mg), Omega 3 fatty acids (180 mg EPA and 120 mg DHA), vitamin E+ Omega 3 and Placebo), as per the double-blind block randomization method. The oxidative stress parameters of the participants were analyzed before and after three month consumption of supplements via enzyme-linked immunosorbent assay method. The level of workers' exposure to noise, was measured according to ISO 9612. Results: Before intervention, mean MDA, SOD and TAC were 27.52 (7.46) nmol/ml, 58.84 (10.44) U/ml and 2.57 (0.67) mM respectively. After intervention, mean MDA, SOD and TAC were 24.57 (7.58) nmol/ml, 63.46 (11.02) U/ml and 2.70 (0.84) mM respectively. The use of supplement Omega 3 fatty acids had a significant decremental effect on MDA levels. The use of vitamin E alongside Omega 3 fatty acids had a significant incremental effect on SOD activity.Conclusion: Noise exposure had a decremental effect on TAC and SOD as well as an incremental effect on MDA, but this was only statistically significant for TAC. It appears that the simultaneous use of vitamin E and Omega 3 fatty acids for three months had a positive effect on the anti-oxidant performance of workers exposed to noise.

The incidence of neoplasm has significantly increased around the world over the last decades, resulting in use of anti-neoplastic drugs and the potential for occupational exposure to these drugs. One of the most commonly used chemotherapeutic drugs for treatment of malignancies is 5-fluorouracil (5-FU). In this study, in order to develop an appropriate adsorbent for selective extraction of ultra-trace 5-fluorouracil from urine samples, molecularly imprinted membranes (MIMs) of 5-FU were prepared by encapsulating molecularly imprinted polymer nanoparticles (MIP-NPs) into the electrospun polyethylene terephthalate (PET) nanofibers. The MIP-NPs encapsulated into electrospun PET nano-fibers were prepared by precipitation polymerization technique. These MIMs were used as selective sorbents for solid-phase extraction (SPE) of ultra-trace 5-FU from different samples prior to the analysis by high performance liquid chromatography (HPLC). Central Composite Design (CCD) was used for optimization of effective parameters in sorption and desorption steps of the molecularly imprinted membrane solid phase extraction (MIMSPE). The optimum operating conditions for the proposed method were pH: 6.2, amount of sorbent: 10.3 mg and absorption time: 20.5 h, the volume of eluent: 1 mL, the composition of elution solvent: the ratio of 90.3:9.7 methanol and acetic acid, and desorption time: 1.27 h. Under these optimized conditions, the limit of detection for 5-FU by MIMSPE was 0.07 μ L-1. The recoveries of 5-FU from urine sample ranged from 92.95±3.85 to 94.85±2.85%. The proposed MIMSPE-HPLC method can potentially be applied for selective detection of 5-FU in real samples with no special sample pretreatment steps.

Background: Phytoremediation is one of the available and simple techniques for removing benzene, toluene, ethylbenzene, and xylene (BTEX) from indoor air. This study aimed to evaluate phytoremediation of low concentrations of BTEX by Hyrcanian plants including Ruscus hyrcanus and Danae racemosa. Methods: The test chamber was used to evaluate the removal of BTEX. Benzene, toluene, ethylbenzene, and xylene were injected into the chamber using Gastight syringes (Hamilton) to generate the concentration of 10 (benzene), 20 (toluene), 20 (ethylbenzene), and 50 (xylene) µL/L Results: Ruscus hyrcanus was able to remove BTEX (10, 20, 20, and 50 µL/L) from air after 3 days. D. racemosa could uptake BTEX (10, 20, 20, and 50 µL/L) from air after 4 days. Removal efficiency was calculated based on leaf area and volume of the chamber. R. hyrcanus showed the highest removal efficiency ranged from 8.5075 mg/m3 /h.cm2 for benzene to 86.66 mg/m3 /h.cm2 for xylene. The increase in BTEX phytoremediation was assessed after repeated exposures. A significant phytoremediation efficiency was obtained after the third injection of BTEX to the chamber. Afterwards, the effects of BTEX on anatomical and morphological structure of plants were studied. The results of Photomicrography showed that tissue structures of leaves and stems changed. Study of D. racemosa and R. hyrcanus stems showed that vascular bundles also changed. The development of crystal in vacuole of spongy parenchyma was the main anatomical change of R. hyrcanus and D. racemose compared to the control samples. Conclusion: It can be concluded that R. hyrcanus and D. racemosa can be used for phytoremediation of indoor air pollution.

Background and Objective: Silica dust is present in almost all mining operations and can cause various health problems such as silicosis in workers. The present study aimed to determine the total and respirable dust levels and the crystalline silica content of the soil in the breathing zone of workers in Iranian mines. Methods: This cross-sectional study was carried out in 2016-2017 on six Iranian silica mines. Dust sampling was performed according to the National Institute of Occupational Safety and Health (NIOSH) method No. 0600. The samples were collected from the respiratory zone of workers at 114 stations in different units of the mines. The silica content was measured using the standard NIOSH method No. 7601. The crystalline silica content in bulk samples collected from the soil was determined by using the X-Ray Diffraction (XRD) spectroscopy method. Results: The highest concentration of crystalline silica dust was 2.81±0.49 mg/m3 and was observed in the air of crushing unit of mine no. 6, and the lowest was 0.08±0.208 mg/m3 and was measured in the management/administration unit of mine no.1. The mean silica content in the solid surface of the mines was 91%. The total and respirable dust levels in all units of the mines except management/administration were higher than the permissible limit. The free silica content of all collected samples was substantially higher than the permissible limits, and in some cases, it was as much as 100 times above the standard level, which reflects the extremely high risk of working in these mines. Conclusion: Exposure of workers with crystalline silica dust in all units was higher than the standard recommended limits. It is imperative to adopt immediate measures based on technical, managerial, and personal protection solutions to reduce the exposure of workers to silica.

Background and Objectives:Occupational exposure to silica dust can lead to biochemical damage. Malondialdehyde (MDA) can be considered as a primary marker for measuring the level of oxidative stress in a living organism. This study was conducted in order to evaluate the level of MDA in blood and urine of mice exposed to silica dust.Material and Methods:In this experimental study, 72 mice (BALB/c) were randomly allocated to five exposed groups and 1 control group. Exposure of mice to pure 99% silica dust was done in closed containers. Blood sampling was performed from the heart of mice and urine sampling fulfilled by insertion into a metabolic cage. The RAOet al. method was used to measure MDA.Results:The highest level of plasma MDA in group 1 in the 4thmonth was 8.4±0.41 nmol/l and the lowest level of MDA was 1.3±0.2 nmol/l in the third sampling in the control group, also the highest amount of urine MDA in the first and second groups and 4 months after exposure was 1.16±0.51 nmol/l, and the lowest in the control group and in the third sampling was 0.48±0.06 nmol/l. A significant difference was found between the levels of MDA in all exposed groups at different times except for the 5thgroup with the lowest concentration (P< 0.05).Conclusion:MDA in blood and urine could be proposed as a good biomarker for the evaluation of biochemical damages caused by silica dust. Measuring MDA is also a simple and inexpensive method that does not require complex equipment and can be used as an early detection test for biochemical damages caused by silica.

A fast and easy surfactant-assisted dispersive micro-solid phase extraction method coupled with ultrasonic power was used for the simultaneous preconcentration and determination of low levels of hippuric and methyl hippuric acid in human urine samples. In the first step, magnetic nanoparticles was coated by titanium oxide nanoparticles (Fe3O4/TiO2 NPs), afterward characterized by the scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. In the next step, anionic surfactants were thus combined with the synthesized magnetic nanoparticles to create a new adsorbent for increasing the simultaneous extraction of hippuric and methyl hippuric acid. After elution of extracted target molecules by the sorbent, the concentration of these molecules were measured by high-performance liquid chromatography (HPLC–UV). Meanwhile, a statistical approach known as Box–Behnken design was applied for optimizing significant parameters. With the optimum parameters anticipated by the experimental design, the limit of quantification (LOQ) acquired was reported to be 3 µg L− 1, and the calibration curve was linear within the concentrations of 3–1000 µg L− 1. Finally, the method was effectively implemented for the determination of low levels of hippuric and methyl hippuric acid in human urine samples.

Background and Objectives:Occupational exposure to silica dust has multiple consequences, including genetic complications. One of the genetic complications is Micronucleus (MN) changes; therefore, this study aims to evaluate the rate of MN formation in mouse lymphocyte cells due to exposure to silica dust.Materials and Methods:Totally 72 male mice BALB/c were selected and categorized into five exposure groups with 12 mice in exposure to the concentrations of 1.3, 3, 8, 12, and 17 mg/m3of 99% pure silica dust and a control group. The mice were exposed to silica dust in which they were exposed for 8 hours a day, 6 days a week, and for 1, 2, 3, and 4 months. Then, blood samples were taken from the mice and the rate of MN formation in their lymphocyte cells was evaluated. The results were analyzed via SPSS software version 21 (PResults:Maximum and minimum averages of dust concentration, related to boxes 1 and 5, were 17 mg/m3and 1.3 mg/m3, respectively. Maximum rate of MN formation was observed in the fourth month of exposure and in group 1 with the value of 21.6±1.15, and minimum rate of MN formation was observed in the third month of exposure and in control group with the value of 3±1. Average of MN frequencies in each of the exposure month was significant related to the control group (P=0.001). There was a direct and significant correlation between exposure concentrations of exposed group and average rate of MN formation (r=0.679).Conclusions:More than 3 months exposure to silica dust may lead to significant MN formation in lymphocytes of mice BALB/c in comparison with the control group.

The WBGT index is a common method to evaluate heat stress in the workplaces based on human physiological responses to environmental conditions. This systematic and meta-analysis study was aimed to estimate the mean value of the WBGT index in industries. The search protocol of this study was carried out according to PRISMA checklist. According to the heterogeneity of studies, a meta-analysis was done using a random effects model. The total value of WBGT index in the world according to this study was obtained 28.92 °C (95% CI: 28. 49–29. 35). The results regarding the fixed effect analysis showed that , average WBGT index before and after 2010, was estimated to be 26.63 °C (95% CI: 26.53–26.73) and 29.78 °C (95% CI: 29.71–29.85), respectively. The mean value of WBGT index in the men and women participants were 29.42 and 24.26 °C, respectively. The finding indicated that the average value of WBGT index is rising over time. The reason for this may be attributed to global warming or lack of proper physical work condition in these environments. It would be alarming for the workers who worked in outdoor environments or hot operating conditions.

Background: An effective process for preventing industrial accidents basically requires a thorough study of the environment, data collection, evaluation, and analysis of this information, determination of corrective action, and its implementation. Risk management provides an integrated framework for this important process. The purpose of this study was to identify the parameters of the risk management process, combine these parameters by fuzzy logic and construct a fuzzy model to obtain the risk management index and finally design a questionnaire with Likert scale to obtain the inputs of this model to evaluate the risk management process. Methods: This descriptive cross-sectional study was conducted in 2018 in Tehran. First, based on library studies and experts' opinions, Jaques non-linear crisis management model was selected, and based on this model, the parameters of the risk management process were extracted. Then, a questionnaire with 22 questions was designed to measure these parameters, the content and face validity of which were evaluated. Also, to evaluate the reliability of the questionnaire, the test-retest method and Cronbach's alpha coefficient were used. Then the parameters were defined as fuzzy numbers, the Fuzzy inference engine was programmed using fuzzy rules, and its validity was evaluated. Results: The fuzzy model has three stages, in each of which sixteen rules are used. In this fuzzy model, the defuzzification step was performed by four methods with the same results. The designed questionnaire contains twenty-two questions, the content validity ratio (CVR) for this questionnaire is 0.89, and the content validity index (CVI) for all questions was above 0.79. Cronbach's alpha coefficient for this questionnaire was 0.713. Face validity was determined quantitatively by calculating the impact score (more than 1.5). Using intraclass correlation coefficient and Pearson correlation coefficient, the existence of reliability between test times (test-retest) was confirmed, so that their values were 0.84 and 0.88%, respectively. Conclusion: The proposed fuzzy model has a high validity giving a correct evaluation of the risk management process and expressing the final result in the form of an index between zero and one hundred. The risk management process evaluation questionnaire has good validity and reliability with the interpretation that the item has good face validity and is understandable, simple, and fluent for the sample group. Using this tool, industry managers can evaluate the safety risk management process, making them able to identify the strengths and weaknesses of this process, and finally take steps to eliminate the defects and improve this process continuously.

Background: Styrene is one of the chemicals used in industries, especially the petrochemical industry, which affects health. Singaporean methods and the WHO use different parameters to assess the carcinogenic risk of the substance. Therefore, this study aimed to compare the level of carcinogenic risk due to exposure to styrene using the Singapore Department of Occupational Health with the risk levels provided using the WHO to achieve high-reliability results. Methods: In this study, 150 air samples were collected from the respiratory area of 50 employees by NIOSH1501 method, after identification of styrene emission units and preparation of identical exposure groups. The samples were analyzed by Varian-cp3800 gas chromatograph. Finally, the risk of styrene's health effects on petrochemical staff was calculated using the method of the Singapore Department of Occupational Health, and the results were compared with the risk levels of styrene presented by WHO. Results: The carcinogenicity of styrene was higher in polybutadiene latex (PBL) (2.3 ) and the fire department (1.3 ) in comparison with the other units. The World Health Organization-defined risk levels predicted 22% of staff to be a "definitive" carcinogenic risk. While the Singapore Department of Occupational Health approached a "low" risk rating. Conclusion: A "low" risk rating was obtained through the Singapore Department of Occupational Health. But the WHO method for 30 years of exposure to styrene predicted "probable risk" and "definitive risk." This showed a high difference in the results of the two semi-quantitative methods used.

BackgroundNeed to a simple, available, accurate, comprehensive, and valid indicator is felt to assess thermal effects. Therefore, the present study was aimed to develop and validate the environmental heat strain risk assessment (EHSRA) index using structural equation modeling (SEM) based on empirical relations.MethodsThis cross-sectional study was performed on 201 male workers in environments with various climatic conditions. The heart rate and tympanic temperature of the individuals were monitored at times of 30, 60, and 90 min after beginning the work. At these times, values of dry temperature, wet temperature, globe temperature, and air velocity were also measured and metabolism rate and clothing thermal insulation value were estimated. At the end, a theoretical model was depicted in AMOS software and obtained coefficients were applied to develop a novel index. The scores of this indicator were categorized into four risk levels via ROC curves and validate using linear regression analysis.ResultsIndirect effect coefficients of the globe temperature, dry temperature, wet temperature, air velocity, metabolism, and clothing thermal insulation variables on the tympanic temperature were computed by 0.77, 0.75, 0.69, 0.24, 0.49, and 0.39, respectively. These coefficients were applied to develop the index. Optimal cut-off points of boundaries between risk levels included 12.02, 15.88, and 17.56. The results showed that the EHSRA index justified 75% of the variations of the tympanic temperature (R2= 0.75).ConclusionsThe novel index possesses appropriate validity. It was suggested that this indicator is applied and validated in various environments in the next studies.

We aimed to investigate the efficiency of neat polyacrylonitrile (PAN) nanofibers and photocatalytic PAN/TiO2 nanofibers for removal of airborne microorganisms.Nanofibers were fabricated from 16 wt% of PAN dissolved in dimethyl formamide through the electrospinning technique. The efficiency of media for removal ofThe mean diameter of electrospun fibers and coefficient of variation were 194 nm and 15%, respectively. The amount of immobilized TiO2 on the filter was 620±6.56 mg/m2. Photocatalytic nanofiber filter media presented the best performance for removal of airborneThe filtration efficiency of photocatalytic media was significantly higher than neat ones. Lower efficiency of media was found in the higher air velocity for all bioaerosols. High UVC radiation intensity increased filtration efficiency. Moreover, the increase in air temperature and relative humidity (except for TiO2-coated media under UVC radiation) did not significantly affect the filtration efficiency of all media.

Background: The present study investigated the effects of exposure to noise and whole body vibration (WBV) on the levels of sex hormones in an automobile parts manufacturing plant.Methods: The level of workers' exposure (n=162) to each of the mentioned stressors, was measured through standard methods and for each person the time-weighted average (TWA) of exposure was calculated. In order to determine serum sex hormones (free testosterone, LH and FSH), blood samples were taken from all participants after 8-10 hours of fasting between 7-9 am and then the blood samples were analyzed by ELISA method. Results: In general, regarding testosterone as the main male sex hormone, only 49% of the participants were in the normal range. In total of three sections, the lowest mean testosterone levels was observed in the third exposure group (WBV>1.93 m/s2; noise >92.69 dB) of the studied stressor, however, only the difference in testosterone levels between the three different groups of exposure to noise was statistically significant (P = 0.001). The relationship between demographic variables and levels of noise and WBV exposure with sex hormones was not linear and only the relationship between noise exposure and testosterone levels was statistically significant (R = -0.201, P = 0.013). Conclusion: According to the results of Logistic Regression, the WBV had the greatest effect on testosterone levels as the main male hormone. However, according to the results of the correlation test, only the relationship between noise exposure and testosterone levels is statistically significant.

In the present paper, micro-mesoporous Fe-MIL-101/OAC composite using in situ incorporation of Fe-MIL-101 into oxidized activated carbon was synthesized and characterized by XRD, FT-IR, SEM, EDS, and BET techniques. The adsorption performances of toluene onto adsorbents in the gas phase were studied using a laboratory-scale dynamic adsorption system under moist ambience. The toluene adsorption capacity of Fe-MIL-101/OAC composite and Fe-MIL-101 were 127 and 97.6 mg g−1, severally. Results revealed that the larger pores in micro-mesoporous Fe-MIL-101/OAC enhanced the molecular diffusion rate. The findings indicated that micro-mesoporous structures played key roles in the capture of toluene molecules. The initial toluene concentration positively affected on toluene adsorption capacity while temperature and humidity negatively affected on toluene adsorption capacity. The Langmuir model and the pseudo-second-order kinetics model described better adsorption process of Fe-MIL-101/OAC composite. Thermodynamic findings determined that toluene adsorption over Fe-MIL-101/OAC was spontaneous, exothermic physisorption. The regeneration of the composite was still up to 72.6% after six cycles. The micro-mesoporous Fe-MIL-101/OAC composite proposes a promising support for the high toluene removal for future.

A newly developed Cu-BDC MOF nanocomposite based on natural sepiolite (Sep) was prepared and characterized using XRD, SEM, EDS, BET, and FTIR techniques. The surface areas of the sepiolite and the Sep/Cu-BDC nanocomposite were obtained as 105.5 m2 g−1 and 270.5 m2 g−1 with average micropore volumes of 0.39 and 0.32 cm3 g−1, respectively. The Sep/Cu-BDC nanocomposite was prepared from the Cu-BDC metal–organic framework with values of 10, 25, and 40% by weight. The synthesized nanocomposite was tested to estimate the adsorption capacity and breakthrough time under various temperature, humidity, and concentration conditions using a designed setup. The aeroqual S500 direct-reading sensor with 0.01 ppm accuracy was used to measure the exact amount of hydrogen sulfide gas (H2S). The produced Sep/Cu-BDC nanocomposites had an extremely high adsorption capacity compared to the primary sepiolite. Among the different adsorbents, the Sep/Cu-BDC (25 wt%) nanocomposite exhibited the highest adsorption capacity of 55.13 mg g−1 (SD = 0.70) and breakthrough time of 46.32 min (SD = 1.53), respectively. Also, the amount of adsorption and breakthrough time of H2S were decreased with increasing moisture and concentration. The pressure drop was also increased slightly. The nanocomposite with 40 wt% of Cu-BDC showed a significant decrease in the adsorption capacity and breakthrough time of H2S. The Sep/Cu-BDC adsorbent was regenerated using thermal regeneration at 190 °C in N2 flow for 4 h, and the results showed that the adsorbent could be used for three consecutive cycles exhibiting excellent recyclability and thermal stability.

Background: activity in hot environments is among the most common physical dangers in work environments that not only creates diseases resultant from heat which influences on staff’s health but also increases job injuries and accidents. Job injuries, diseases, and reduction in workerschr('39') efficiency in exposure to heat stress have caused increasing anxiety. Most of the study results are demonstrative of diseases as a result of heat and less related to job injuries and accidents. Therefore, the present study aims at reviewing previous studies in the field of job injuries and accidents in exposure to the work environmentchr('39')s heat stress. Methods: this review study has systematically reviewed publications and articles from 2000 to 2019 in databases. Keywords including "heat stress”, “heat strain”, “heat exposure”, “heat wave", "heat injuries”, “job accidents”, “job exposure”, “hot environment” and “air change" have been used and finally, 30 articles included into the study. Results: study articles consist of 29 jobs and 1 military environment. Study occupations consist of one study about military forces, textile, aluminum smelting, cleaners of oil reservoirs, two studies about mineworkers and metal and iron industries, three studies about building workers, four studies about agricultural workers and 15 studies about different occupations. Also, 11 studies conducted in open environments, seven studies in closed environments and 12 others conducted both in open and closed environments. 17 analytical studies, three correlational, cross-sectional, cohort studies, one cohort, and descriptive study and two descriptive-analytical studies have been conducted. Most job injuries and accidents happened during summer and men especially the young have involved in such problems and job injuries and accidents have increased due to extreme temperature increase. Generally, job injuries and accidents include burn, slip, collision with things and collision with mobile things. Conclusion: there is a strong relationship between temperature in hot environments and risk increase in injuries and accidents of work environments which differ based on employeeschr('39') features (such as age, gender, occupation, and industry). However, dominant mechanisms on the happening of such injuries have not been determined yet. It necessitates more expertise to determine especial injuries and accidents happening in hot environments. Policymakers and employers have to be more aware of job injuries and accidents in heat exposure and suitable educational resources have to be provided to prevent such injuries.

Biomanipulation is reliable method for treating volatile organic compounds (VOCs) in polluted air. The performances of two biofilters in the removal of toluene vapors from air stream were compared. Two identical biofilters designed in parallel configuration were operated in lab-scale for 20 days; one of them was filled by sterilized media (compost and wood charcoal 2:1 v/v) and another was filled by the same media inoculated with Pseudomonas putida PTCC 1694, as a native strain. Moreover, batch tests were performed to determine the biodegradation rate of toluene. The results showed that, in comparison with the sterilized BF (89% vs 58%), the inoculated BF could effectively eliminate toluene from air stream. The pressure drop across the inoculated BF and the sterilized BF were 0.66±0.28 and 0.47±0.27 mm water respectively. The batch test results showed that loss of toluene in the control bottles was greater than the blanks. Based on the experimental results, inoculated BFs can effectively treat toluene vapors from gaseous streams.

Background: The cognitive function could be affected following exposure to organic solvents.The purpose of this study was to examine the cognitive performance of workers exposed to different levels of organic solvents in a painting unit of an automotive industry. Methods: This case-control study was conducted, in 2017, on 121 and 111 workers from the painting and assembly units of an automotive industry as the case and control groups,respectively. Exposure of workers to organic solvents were determined according to National Institute for Occupational Safety and Health (NIOSH) method. The cognitive performance of the studied population was evaluated by the computerized tests. Results: The obtained scores of the N-Back in 1 and 2 blocks and the simple reaction time tests(SRTTs) were significantly differed in the exposed group (p 0.05). Moreover, a significant relationship between the hazard quotient and the cognitive function test scores were observed except the Stroop test. Conclusion: Exposure to organic solvents affect the cognitive functions even below the Occupational Exposure Limits (OELs). Moreover, workers with high exposure levels of organic solvents had highest risk of poor memory and reaction time.

Background: This study was conducted to investigate the heat stress and semen quality among male workers in a steel industry in Iran and investigate the relationship between heat stress indices and semen parameters. Methods: The study was conducted on workers exposed (n = 30) and unexposed (n = 14) to heat in a steel industry. After obtaining a brief biography of the selected employees, scrotal temperature, oral temperature, and environmental parameters were measured, and their semen samples were analyzed according to the procedure recommended by the World Health Organization. The heat stress indices, including wet-bulb globe temperature (WBGT) and predicted heat strain (PHS), in their workplace were calculated according to environmental parameters (ISO 7243:1989 and 7933:2004, respectively). Results: Time-weighted averages of WBGT and PHS (35.76°C and 491.56 w/m2wm2, respectively) for the exposed group were higher than threshold limit values. The mean difference of environmental, physiological, and semen parameters (exception: pH of semen), and also WBGT and PHS indices were statistically significant (p

Urban air pollution caused by fine particles, the increasing development of nanotechnology and the spread of contagious diseases, as well as bioterrorism, has raised concerns about aerosols and bioaerosols. This research aims to study the effect of various parameters on the diameter and uniformity of electrospun polyurethane/chitosan nanofibers and to evaluate their filtration performance and antimicrobial activity against nanoaerosols and Escherichia coli (E. coli) bacteria as a model bioorganism, respectively. Using response surface methodology, the main and interactive effects of four parameters including polyurethane/chitosan weight ratio, applied voltage, needle tip-to-collector distance and polymer flow rate were investigated on the mean diameter and uniformity of electrospun nanofibers. The nanoparticle filtration efficiency of the polyurethane/chitosan electrospun nanofiber filter was determined after preparation under recommended optimum conditions using a standard filtration test rig. There was an increase in the mean diameter of nanofibers and decrease in the uniformity of them with increase in polyurethane polymer solution concentration. The mean diameter of nanofibers decreased significantly with increasing applied voltage and chitosan content in polyurethane/chitosan blended polymer solution. A significant, positive correlation was seen between needle tip-to-collector distance, polymer flow rate and the mean diameter of nanofibers. The prepared nanofiber filters showed an acceptable range of quality factor and pressure drop for using in filtration applications such as industrial filtration processes and personal respiratory protection equipment. The results of the performing bacterial disk diffusion method indicated that electrospun polyurethane/chitosan nanofibers have good antibacterial activity against E. coli bacteria as a model microorganism.

Since the body dissipates heat mostly through radiation, conduction, convection and evaporation, textile material for heat transfer can play a significant function in human thermal comfort and personal thermal cooling. Most people in developed parts of the world, particularly in tropical and subtropical regions, rely on highly energy‐intensive, and inefficient central cooling systems to achieve thermophysiological comfort which is rarely satisfactory. The present study focused on strategies used to produce advanced functional phonetic (passive cooling) fabrics for personal thermal control and saving energy programs. Recent technological advances in clothing industry have provided the opportunity to explore the fundamental physical properties and practical applications of clothing to humans. Also, we explained that nanoparticles and polymers could be coated to fabricate advanced textiles which are lightweight and flexible and have excellent personal thermal management. We discussed some of these textiles with engineered technology at passively monitoring routes of heat dissipation by the human body, advantages and drawbacks of different types of clothing, and sensitive fabrics that offer adaptive personal cooling capacity. An outlook discussing considerable challenges, perspectives, and alternatives for thermal management clothing is also presented. Finally, some perspectives regarding thermal management clothing are provided for future research.

This paper presents the sound absorption performance of natural fiber composites developed from chrome shave (CS) and coffee silver skin (CSS). Twelve test samples of thickness 30 mm and 50 mm were fabricated with different fiber sizes and fiber ratios and by maintaining the density of the samples by 150 kg/m3. Normal incidence sound absorption coefficient spectra were measured in an impedance tube. Absorption coefficient spectra were predicted using the Johnson-Allard-Champoux (JCA) model using best fit values of tortuosity and the two characteristic lengths together with measured values of porosity and flow resistivity. The results revealed that the CS-CSS composite had average absorption coefficient of 0.95 above 1 kHz for a thickness of 30 mm and 50 mm. 'The predictions and data are in good agreement up to 6 kHz.

This study is centered around establishing an efficient, simple and reliable surfactant assisted dispersive micro solid-phase extraction method followed by the accurate trace determination of HA and MHA as biomarkers for exposure to toluene and xylene. To achieve the above goal, Fe3O4@SiO2@sodium dodecyl sulfate was employed for the extraction of two compounds from various environmental water and urine samples. Due to its superb dispersibility and appropriate structure after modification by SDS, the Fe3O4@SiO2@SDS sorbent exhibited a great deal of improvement in the extraction efficiency. Once the extraction of analytes had been achieved, they were desorbed from the sorbent using an appropriate solvent followed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Under the optimal extraction conditions, the calibration curves for the analytes were linear over the concentration range of 1–1000 μg L−1 for water media and 5–4000 μg L−1 for urine media. The accuracy of the method was tested by relative recovery experiments on fortified real samples with the results falling within the range of 96 to 103.3%. Based on a signal-to-noise ratio of 3 (S/N = 3), the method detection limits were determined to be 0.2 μg L−1 and 0.5 μg L−1 for HA and MHA, respectively.

In this work, natural zeolite, clinoptilolite were treated with acid (0.6 N HCl; code “Z-AM”) and alkaline solutions (1.5 N NaOH; code “Z-BM”). Thereafter, non-modified (as parent zeolite; code “Z-NM”) and modified zeolites were impregnated with cobalt using wet incipient impregnation method (Codes: “Z-AM-Co-0.5,1,1.5”, “Z-BM-Co-0.5,1,1.5”, “Z-NM-Co-0.5,1,1.5”). The prepared zeolites were characterized by XRD, ICP-OES, BET, NH3-TPD and H2-TPR. Also, these materials were studied for the catalytic decomposition of nitrous oxide (a greenhouse gas) to nitrogen and oxygen. The obtained results showed that the applied modifications had no significant influence (destruction) on the main structure of the zeolites including clinoptilolite, quartz and cristobalite. In addition results showed that acid modification increases the nitrous oxide decomposition because of surface area increment and the higher amount of CO/Al as well as the strong acid sites of this zeolite compared to other zeolites. Also, experiments showed that the main active species in nitrous oxide decomposition are mono-atomic (Co2+ cations) and other species exhibit much lower activity. In conclusion, natural clinoptilolite zeolites treated with acid and impregnated with Cobalt (Z-AM-CO-1.5) could be a very effective and cost-benefit catalyst for reducing N2O as a greenhouse gas, due to its very low price, high chemical stability and high availability.

The aims of this study were (a) to assess the agreement coefficient between tympanic temperatures and the most popular and valid heat stress index, wet bulb globe temperature (WBGT), in outdoor environments; (b) to determine a cut-off point for tympanic temperature as a heat strain index for evaluation of outdoor workers.1452 measurements of WBGT index and tympanic temperature were recorded for outdoor workers from nine different climatic regions. Consistency of the WBGT and tympanic temperature were tested. The cut-off point for tympanic temperature in outdoor environments regarding WBGT evaluation was suggested based on obtained sensitivity and specificity from a receiver operating characteristic curve.The results showed that there were numerous situations in which WBGT exceeded the reference value, whilst the measured values of tympanic temperature rarely reached a permissible value for core temperature (38 °C). Therefore, appropriate consistency of results between the heat stress and strain indices was not achieved.The criterion of tympanic temperature equaling 37 °C was suggested as a cut-off point for tympanic temperature as a heat strain index for outdoor environment evaluation.