Wet Bulb Globe Temperature Index Research Articles

Heat stress and incidence of acute kidney injury among agricultural workers in Spain

BackgroundHeat stress is associated with adverse health outcomes among workers, including acute kidney injury. We aimed to estimate the incidence of acute kidney injury over the course of the work shift and the association with heat stress among agricultural workers in Spain, where summer temperatures are high and heatwaves are expected to be frequent. MethodsMale agricultural workers were enrolled in two different harvesting seasons and provinces, as follows: summer in Alacant (n=43; September, 2018) and winter in Tarragona (n=52; November, 2018, and January, 2019). For each participant, we estimated exposure to heat stress during a work shift based on the wet bulb globe temperature (WBGT) index and acute kidney injury cross-shift incidence, defined as an increase in post-shift serum creatinine by at least 0·3 mg/dL or at least 1·5 times the pre-shift serum creatinine concentration. We collected information on confounders. For a subsample of participants (n=54), we measured neutrophil gelatinase-associated lipocalin (NGAL) concentrations before and after the working shift. We used regression models to assess if heat stress was a risk factor for acute kidney injury and increase in NGAL concentrations. FindingsThe mean WBGT was 24·5°C (SD 2·0; range 20·2–27·1) during the summer season and 14·2°C (8·0–20·7) during the winter season. Nine (21%) of 43 workers harvesting during summer were exposed to heat stress. Incidence of acute kidney injury was higher during the summer season (14 [33%] of 43 workers vs two [4%] of 52 workers). Heat stress was associated with cross-shift incidence of acute kidney injury (age-adjusted odds ratio 9·6, 95% CI 1·4–67·9). No differences in NGAL concentrations were observed between participants exposed to heat stress. InterpretationHeat stress is a risk factor for acute kidney injury among agricultural workers in Spain, even when environmental temperatures are not extreme. Monitoring acute kidney injury incidence among agricultural workers in Spain is important in the context of climate change, as frequent episodes of acute kidney injury can lead to chronic kidney disease. FundingCarlos III Health Institute and European Union.

Evaluation of Heat Stress Levels Inside Greenhouses during Summer in Korea.

Farmers working inside greenhouses during summer are at risk of heat-related illness. In this study, we compared the dry-bulb temperatures (DTs) and the wet-bulb globe temperature (WBGT) index inside and outside greenhouses. We then determined the criteria for appropriate working and resting times inside greenhouses. The measurements were performed during the hottest period in 2020 and 2021 for two greenhouses, representative of those commonly found in rural areas. A direct-reading WBGT index meter was used for these measurements, and Automated Synoptic Observing System (ASOS) data were used to obtain regional DT data. DTs inside the greenhouses were significantly higher than the ASOS DTs (p < 0.001). In addition, the August WBGT index inside was significantly higher than that outside the greenhouses (p < 0.001). We found that the temperature during the period between 08:00 and 19:00 exceeded the international threshold of 28 °C for heat-acclimatized workers performing moderate-intensity work, above which heat stress becomes a concern. Our results revealed that the thermal index inside can be significantly higher than that found outside greenhouses. Therefore, when work is required inside greenhouses during the summer, stricter standards and safety measures should be considered.

Objectively-assessed physical activity and heat stress and the association with kidney function in female harvest workers in Spain

BACKGROUND AND AIM: Physical activity (PA) in hot environments has been associated with kidney damage. In harvest workers, PA has been primarily assessed by questionnaires in males. We aimed to study the association between objectively-measured PA intensity and incidence of acute kidney injury (AKI) over the course of one work shift, in female harvest workers in Spain. METHODS: Ninety women working in greenhouses wore a Zephyr chest harness to measure PA intensity during one regular work shift in June 2020. We determined the mean (PA_mean), standard deviation (PA_sd), and 3-minute-maximum (PA_max, a proxy of peak PA intensity) of PA intensity (vector magnitude units). We estimated heat stress (HS) in greenhouses based on wet bulb globe temperature index (ISO 7243:2017). Serum creatinine and neutrophil gelatinase associated lipocalin (NGAL) levels were measured before and after the work shift. AKI was defined as an increase in post-shift serum creatinine by at least 0.3 mg/dl or at least 1.5 times the pre-shift serum creatinine levels. Additionally, we calculated pre-post-shift differences in NGAL. We used logistic regressions adjusted for age, body mass index, and HS. HS was also assessed as an effect modifier. RESULTS: PA_sd and PA_max seemed to be associated with AKI (OR=1.57 (95%CI=0.82;3.21) and 1.41 (0.71;2.85), respectively), but not PA_mean. There was no interaction between any of the PA variables and HS (p-value LRT&amp;#x3e;0.1). Mean (SD) increase in NGAL levels over the course of a work shift was higher among participants with AKI (27.8 (7.5)) compared to those without AKI (12.2 (2.7)). CONCLUSIONS: Results suggest that large changes and peaks in PA intensity should be avoided to protect renal function of harvest workers. Increased levels of NGAL among those with AKI are indicative of kidney damage among those with increased serum creatinine levels. KEYWORDS: Occupational physical activity, acute kidney injury, ambient heat stress

Heat stress and incidence of acute kidney injury among agricultural workers in Spain

BACKGROUND AND AIM Heat stress (HS) is associated with adverse health outcomes among agricultural workers, including acute kidney injury (AKI). The aim on this study was to estimate the incidence of AKI over the course of the work shift and the association with HS among agricultural workers in Spain, where summer temperatures are high and heat waves are expected to be more frequent. METHODS Male agricultural workers were enrolled in the study in two different periods and provinces: summer harvesting season in Alacant (n=43, September 2018) and winter harvesting season in Tarragona (n=52, November 2018 and January 2019). For each participant we estimated exposure to HS during a work shift based on the wet bulb globe temperature (WBGT) index (ISO 7243:2017) and AKI cross-shift incidence, defined as an increase in post-shift serum creatinine by at least 0.3 mg/ dl or at least 1.5 times the pre-shift serum creatinine levels. We collected information on potential confounders. For a subsample of participants (n=54), we measured neutrophil gelatinase-associated lipocalin (NGAL) levels before and after the working shift. We used regression models to assess if heat stress is a risk factors for AKI and increase in NGAL levels. RESULTS Mean WBGT was 24.5 ᵒC (20.2-27.1) during the summer harvesting season and 14.2 ᵒC (8.0-20.7) during the winter harvesting season. Nine percent of workers harvesting during the summer months were exposed to HS. Incidence of AKI was higher during the summer harvesting season (33% versus 4%). HS was associated with cross-shift incidence of AKI [Age adjusted OR (95%CI) =9.6 (1.4, 67.9)]. No differences in NGAL levels were observed between participants exposed to HS. CONCLUSIONS Heat stress is a risk factor for AKI among agricultural workers in Spain even when environmental temperatures are not extremely hot. KEYWORDS Heat stress, Acute kidney injury, Agricultural workers, Mediterranean region

Hematological parameters in a population of male bakers exposed to high heat work environment.

The aim of this study was to determine the hematological changes associated with heat exposure in a population of bakers. Personal information was collected using a questionnaire, and a venous blood sample was drawn at the end of a work shift from the bakers and from a control group. The average wet-bulb globe temperature (WBGT) index was measured in the workplaces of both the bakers and the controls. This cross-sectional study involved 137 bakers working in 20 bakeries and 107 controls who were comparable in terms of likely confounding factors. Hemoglobin and platelet values were abnormal among the bakers and statistically significantly different to the control group (P = 0.026, and P = 0.016 respectively). The average WBGT index in the bakeries was 37.4°C, while the average WBGT in the workplaces of the controls was 25.5°C, (P<0.0001). The changes in the bakers' hematological parameters were found to be associated with exposure to high environmental heat at bakeries, as measured by the WBGT index. Preventive measures should be introduced to reduce the adverse effect of heat exposure among bakers and directed toward the worker-equipment-environment triad.

The impact of humidity on Australia’s operational heatwave services

More frequent and intense heatwaves in the last decade have challenged humanitarian, health and meteorological authorities to mitigate impact. Meteorological heatwave monitoring and prediction services vary between heatwave definitions which either include humidity or are based only on temperature. Incorporation of humidity into human health heatwave studies and warning services has been variable. Whilst higher humidity is a known stressor during heatwaves, humidity is known to confound interpretation of heatwave data and can be difficult to monitor and forecast.This study examines the effect of humidity on diagnosed heatwave severity across Australia’s diverse climate zones. Dry bulb temperature is used as the only input into the Bureau of Meteorology’s current operational Excess Heat Factor (EHF) index. Alternative humidity-affected temperature indices (Apparent Temperature, Wet Bulb Globe Temperature and Heat Index) are examined for suitability as input to EHF to compare the incidence of dry and humidity-affected heatwave severity within Australia. This paper uses maximum and minimum dry and humidity affected temperature indices extracted from Australia’s Bureau of Meteorology Atmospheric high-resolution Regional Reanalysis for Australia (BARRA).Our investigation demonstrates Australia’s operational temperature-only percentile-based heatwave severity service provides effective heatwave warning guidance for five of Australia’s six diverse climate zones. However, rare very dry or very humid heatwaves in the tropics require both dry bulb temperature-only and Heat Index versions of Excess Heat Factor (EHF) severity index to provide competent operational heatwave early warning guidance.

Investigation of Spatio–Temporal Changes in Land Use and Heat Stress Indices over Jaipur City Using Geospatial Techniques

Heat waves are expected to intensify around the globe in the future, with a potential increase in heat stress and heat-induced mortality in the absence of adaptation measures. India has high current exposure to heat waves, and with limited adaptive capacity, impacts of increased heat waves might be quite severe. This paper presents a comparative analysis of urban heat stress/heatwaves by combining temperature and vapour pressure through two heat stress indices, i.e., Wet Bulb Globe Temperature (WBGT) and humidex index. For the years 1970–2000 (historical) and 2041–2060 (future), these two indicators were estimated in Jaipur. Another goal of this research is to better understand Jaipur land use changes and urban growth. For the land use study, Landsat 5 TM and Landsat 8 OLI satellite data from the years 1993, 2010, and 2015 were examined. During the research period, urban settlement increased and the majority of open land is converted to urban settlements. In the coming term, all months except three, namely July to September, have seen an increase in the WBGT index values; however, these months are classified as dangerous. Humidex’s historical value has been 21.4, but in RCP4.5 and RCP8.5 scenarios, it will rise to 25.5 and 27.3, respectively, and slip into the danger and extreme danger categories. The NDVI and SAVI indices are also used to assess the city’s condition during various periods of heat stress. The findings suggest that people’s discomfort levels will rise in the future, making it difficult for them to work outside and engage in their usual activities.

Research progress of heatstroke warning system

With global warming and frequent heat waves, the incidence of heat-related-illness has gradually increased, and heatstroke is the most serious clinical syndrome, with high mortality and incidence of sequelae. Effective heatstroke warning aims to reduce the incidence and the harm of heatstroke by monitoring certain parameters and forecasting the possibility of suffering heat illness, however, there is no unified summary of the heatstroke early warning system at present. The occurrence of heatstroke involves two key aspects: climate environment and individual susceptibility, and individual susceptibility is manifested as the difference in heat tolerance ability. This article represents the current early warning system of heatstroke from climate environment, such as effective temperature, heat index, wet bulb globe temperature (WBGT) index, somatosensory temperature, etc., and individual susceptibility, for the reference of research and development in this field.

Wet-Bulb Globe Temperature, Universal Thermal Climate Index, and Other Heat Metrics for US Counties, 2000–2020

Epidemiologic research on extreme heat consistently finds significant impacts on human morbidity and mortality. However, most of these analyses do not use spatially explicit measures of heat (typically assessing exposures at major cities using the nearest weather station), and they frequently consider only ambient temperature or heat index. The field is moving toward more expansive analyses that use spatially resolved gridded meteorological datasets and alternative assessments of heat, such as wet-bulb globe temperature (WBGT) and universal thermal climate index (UTCI), both of which require technical geoscientific skills that may be inaccessible to many public health researchers. To facilitate research in this domain, we created a database of population-weighted, spatially explicit daily heat metrics – including WBGT, UTCI, heat index, dewpoint temperature, net effective temperature, and humidex – for counties in the conterminous United States derived from the ERA5-Land gridded data set and using previously validated equations and algorithms. We also provide an R package to calculate these metrics, including gold-standard algorithms for estimating WBGT and UTCI, to facilitate replication.

THERMAL COMFORT OF UGLJEVIK TOWN FOR THE YEAR 2021 OBSERVED THROUGH THE BIOCLIMATIC INDEX WBGT

&amp;lt;p&amp;gt;This paper researches thermal comfort of the town of Ugljevik in Bosnia and Herzegovina for the year 2021, by analyzing bioclimatic index Wet bulb globe temperature (WBGT). The analysis is a continuation of the research on the bioclimatic conditions of the area of Semberija plain and Majevica mountain, which has so far covered only the city of Bijeljina, as the most urbanized area of the researched space. All five categories of the WBGT index are present during a year, with different number of days for each category. For thermal comfort the most important factors should be observed during summer months of the year, June, July and August, due to the highest number of days in categories with values over 28, that are dangerous for human organism and outdoor activities. The accent in this research was put on the number of categories that are present during one month, but also during just one day, by using mean, maximum and minimal temperatures for calculations. This type of research allows us to see how many different categories one day has.&amp;lt;/p&amp;gt;

Consistency assessment between summer simmer index and other heat stress indices (WBGT and Humidex) in Iran's climates

This study aimed to assess the applicability of summer simmer index (SSI) in different climates of Iran and compare it with other common heat stress indices including WBGT and Humidex. The daily mean air temperature and relative humidity were obtained from the Meteorological Organization of Iran for the 60-year period between 1957 and 2016. Statistical tests including Pearson correlation coefficient and linear regression tests were used to consistency assessment between Summer Simmer Index and wet-bulb globe temperature (WBGT) and Humidex indices. The results of the present study showed that the SSI is significantly correlated with both WBGT and Humidex indices (R2 > 0.932, p < 0.001). In addition, the obtained correlation between SSI and Humidex was higher than correlation between SSI and WBGT in all the climates. Moreover, SSI in the Mediterranean region shows less correlation with both WBGT and Humidex indices (R2 = 0.932 and 0.964 for WBGT and Humidex, respectively). The highly correlation coefficients were observed between SSI and WBGT and Humidex indices, and also between SSI and other environmental parameters; moreover interpreting of SSI is easy, so it can be suggested that SSI can be used as an alternative index for WBGT or Humidex in assessment of heat stress in different climates of Iran.

Heat stress morbidity among US military personnel: Daily exposure and lagged response (1998-2019).

Heat stress illnesses represent a rising public health threat; however, associations between environmental heat and observed adverse health outcomes across populations and geographies remain insufficiently elucidated to evaluate risk and develop prevention strategies. In particular, military-relevant large-scale studies of daily heat stress morbidity responses among physically active, working-age adults to various indices of heat have been limited. We evaluated daily means, maximums, minimums, and early morning measures of temperature, heat index, and wet bulb globe temperature (WBGT) indices, assessing their association with 31,642 case-definition heat stroke and heat exhaustion encounters among active duty servicemembers diagnosed at 24 continental US installations from 1998 to 2019. We utilized anonymized encounter data consisting of hospitalizations, ambulatory (out-patient) visits, and reportable events to define heat stress illness cases and select the 24 installations with the highest case counts. We derived daily indices of heat from hourly-scale gridded climate data and applied a case-crossover study design incorporating distributed-lag, nonlinear models with 5days of lag to estimate odds ratios at one-degree increments for each index of heat. All indices exhibited nonlinear odds ratios with short-term lag effects throughout observed temperature ranges. Responses were positive, monotonic, and exponential in nature, except for maximum daily WBGT, minimum daily temperature, temperature at 0600h (local), and WBGT at 0600h (local), which, while generally increasing, showed decreasing risk for the highest heat category days. The risk for a heat stress illness on a day with a maximum WBGT of 32.2°C (90.0 °F) was 1.93 (95% CI, 1.82 - 2.05) times greater than on a day with a maximum WBGT of 28.6°C (83.4 °F). The risk was 2.53 (2.36-2.71) times greater on days with a maximum heat index of 40.6°C (105 °F) compared to 32.8°C (91.0 °F). Our findings suggest that prevention efforts may benefit from including prior-day heat levels in risk assessments, from monitoring temperature and heat index in addition to WBGT, and by promoting control measures and awareness across all heat categories.

Physiological and biochemical parameters among a population of bakers exposed to environmental heat.

The aim of this study was to determine the physiological and biochemical changes among bakers, induced by heat exposure at the workplace. Information was collected by means of a self-administered questionnaire. Vital signs were measured and recorded by a trained nurse before and after each work shift. A venous blood sample was drawn at the end of each work shift. The mean wet-bulb globe temperature (WBGT) index in the bakeries and offices was measured. This was a cross-sectional study involving 137 bakers working in 20 bakeries, and 107 control subjects comparable in terms of age, race, marital status, years of service, income, and cigarette smoking. There was a significant weight loss and increase in the respiratory rate, the heart rate, and oral body temperature among the bakers compared to the control group. Sodium levels were significantly lower, while blood urea nitrogen levels were significantly higher, among the bakers than in the control group. There were unfavorably hot working conditions in the bakeries: the WBGT index in the bakeries was 37.4°C while the average WBGT for the offices was 25.5°C. The changes in the physiological and biochemical parameters among the bakers were found to be associated with exposure to high environmental heat in the bakeries, as judged by the WBGT index. Preventive measures should be aimed at reducing the adverse effects of heat exposure among bakers and should be directed towards the man-machine-environment triad. Int J Occup Med Environ Health. 2022;35(3):265-72.

Analyzing occupational heat stress using sensor-based monitoring: a wearable approach with environmental ergonomics perspective.

Occupational heat stress could impose a greater risk of heat-related morbidities among the exposed users, declining their work productivity and contributing to a financial burden. This necessitate the implementation of adequate preventive measures and control policies to improve the users’ well-being and productive capacity. The emergence of modernistic sensors gives rise to workplace heat stress monitoring at a substantially lower cost than expensive conventional equipment. Present work unveils the productive role of sensor-based safety helmet, which could monitor the environmental variables, heat stress indices, and users' physiological variables as an indicator of heat strain. The proposed safety helmet was tested under three different work environments with users' engaged in specific work activities. Notable variations were perceived among the measured data under respective work conditions and physical activity performed. Higher heat risk exposures were attributable to the outdoor condition compared to indoor work conditions. For wet bulb globe temperature index, strong association (p-value < 0.01) was observed with fighter index of thermal stress (R2-value = 0.959) followed by discomfort index (R2-value = 0.899) and heat index (R2-value = 0.867). Results revealed a rise in measured physiological parameters under the heavy workload activity (shoveling task; outdoor location) followed by hacksaw cutting task (indoor location), while least values were associated with light workload activity (drilling task; indoor location). The proposed design intervention could be considered an effective site-specific solution for monitoring heat stress exposures and keeping exposed users well aware of the prevalent thermal work conditions at the individual level.

Limitations of WBGT Index for Application in Industries: A Systematic Review

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.

Occupational Heat Stress in the Floriculture Industry of Ethiopia: Health Risks and Productivity Losses

Background: The Ethiopian flower industry is growing fast with successful diversification of export products under greenhouse structures. Higher temperatures in the greenhouses pose a serious threat to the health of workers and add to the risk of occupational heat stress. Excessive heat in workplace settings also reduces work capacity and labour productivity. This study aims to investigate the level of heat exposure, and workers’ and managers’ perceptions and behavioural responses towards extreme heat exposure in a warming climate. Methods: We used the Wet Bulb Globe Temperature (WBGT) measured in representative greenhouses to capture the heat exposure during hotter and cooler seasons following ISO 7243 (generally risk of heat stress occurs when WBGT exceeds 26°C). A comparative cross-sectional study design with a stratified sampling method was used to assess occupational heat stress and workers’ perceptions of the impact of heat on their health and productivity in six different floriculture greenhouses in Ethiopia representing three different agro-ecologies and products. A questionnaire survey was conducted (30 managers/supervisors and 305 workers; 76.1% female) to capture perceptions on heat exposures, symptoms of potential health impacts, productivity losses and coping mechanisms. Results: Heat exposure varied across different agroecologies, product types and greenhouse materials with a median WBGT Index of 25.5°C and a range from 18.1°C to 31.5°C. The impact of heat stress also varied across different employment sectors and geographical regions. Overall, workers in cut-flower greenhouses are exposed to higher than recommended WBGT Index (26°C) for 3 - 6 working hours daily. 65% of the managers reported that heat stress has a significant impact on the workers’ labour productivity, but do not have guidance about working in hot conditions. Workers reported more heat-related health issues and reduced productivity, especially in the mid-altitude greenhouses. About 50% of the workers reported that heat exposure decreased work productivity during hot hours. Sweating, exhaustion, heat-rashes, dehydration, crumps, nausea and headache were self-reported health issues. Labour productivity losses ranged from no loss to 19.5% in the mid- and low-altitudes. Conclusions and Recommendations: Excessive workplace heat in the greenhouses is both an occupational health hazard and detrimental to productivity in the floriculture industry. However, the level of understanding and actions on the ground regarding occupational heat stress are low. The code of conduct in place now does not consider the occupational heat stress issues. Multiple actions (engineering, management, training and policy-related recommendations) have to be implemented by Ethiopian Horticultural Producers and Exporters Association (EHPEA) and farm owners to mitigate heat stress and loss of productivity. Designing and implementing these heat prevention strategies and incorporating them into the code of conduct is in the interests of both employers and employees.

Bioclimatic performance of wet coffee processing facilities: conditions for workers and coffee

This study aimed to evaluate the bioclimatic performance of three wet coffee processing facilities in Colombia, focused on the conditions for workers and coffee parchment, through computer simulation. In addition to temperature and relative humidity, the Wet-Bulb Globe Temperature index (WBGT) was simulated during the highest coffee production month. The proposed simulation model was able to predict hygrothermal behavior within the three coffee processing facilities. Case 3 presented the warmest environment, and case 2 the most humid environment concerning the appropriate conditions for the coffee and the worker. The WBGT index limit was exceeded in case 3. Since this type of facility emits large amounts of heat and steam, constructive modifications are suggested to improve the environmental conditions of workers and coffee. Mainly, the physical separation of the heat exchangers is recommended, which ideally should be outside the post-harvest facility. The steam produced in the drying process should be quickly evacuated with ventilation strategies. Additionally, the use of strategies that reduce the energy gain from solar radiation is suggested.

Trend Analysis and Temporal and Spatial Distribution of Wet Bulb Globe Temperature as a Heat Stress Index in Iran during the Summer Season over a 30-year Period

Introduction: Global warming is one of the most important environmental problems that have raised researchers’ attention. The present study aimed to analyze heat stress trends using the Wet Bulb Globe Temperature (WBGT) index in the country of Iran during the summer over a 30-year period. Materials and Methods: Daily summertime statistical data regarding mean temperature and mean relative humidity, taken from 40 synoptic meteorological stations across Iran during a 30-year period were obtained from the Iranian National Meteorological Department. The De Martonne climate classification system was used to categorize various climate regions of Iran. The WBGT index was calculated using the formula given by the Australian Bureau of Meteorology. The Mann-Kendall statistical test and the Sen's slope estimator were used to analyze the trends of the WBGT index. Results: The WBGT index had an upward trend during the three months of June, July, and August in 71.42%, 57.14%, and 66.66% of all stations and this trend was statistically significant in 53.32%, 50%, and 42.85% of those stations, respectively. Moreover, throughout the summer, 45% of the WBGT index measurements were in the medium range (18-23°C), 37.5% were in the high range (23-28°C), and 17.5% were in the very high range (&gt; 28°C). Conclusion: The WBGT index followed an upward trend during the summer, especially in semi-arid regions of Iran. Considering the phenomenon of global warming, it is essential to monitor, plan ahead, and take necessary precaution measures for sensitive populations who are at high risk areas of the country.

Heat Exposure and Physiological Changes among Cooks

Cooks who are exposed to heat produced from stoves when working in the kitchen are at risk of thermal stress and heat-related illness. Physiological changes such as increased heart rate, sweat production and blood pressure may also affect them. This study aimed to determine the area heat exposure levels and physiological changes including core body temperature, blood pressure and heart rate during pre-, mid- and post-shift among cooks and its association, and to compare the mean difference of physiological changes between the shifts. This cross-sectional study utilised the purposive sampling method and recruited 30 cooks from food stalls and cafeterias in Kelantan. Area heat measurements were collected from 14 sites (7 inside and 7 outside the USM Health Campus). Wet-bulb Globe Temperature (WBGT) monitor was mounted on a tripod at 1.1 m height near the source of heat for 8 hours. The core body temperature, blood pressure, and heart rate were taken three times per day during pre-, mid- and post-shift for physiological changes measurement. Respondents’ personal information, health history, work description, and symptoms of heat-related illness were collected using a questionnaire. The overall WBGT area levels at each sampling site were homogeneously distributed. There was significant increase in core body temperature and heart rate from pre-shift to post-shift. However, there was no significant correlation (p&gt;0.05) between heat exposure (WBGT index) established with the physiological changes. This may suggest that the increase in core body temperature and heart rate might be attributed to other factors and needed further investigation.

Experimental Investigation on Thermal Comfort of COVID-19 Nucleic Acid Sampling Staff in Hot and Humid Environment: A Pilot Study of University Students

The current situation of Coronavirus Disease 2019 (COVID-19) prevention and control coupled with the need to work in high-temperature harsh environments makes it necessary to ensure the health and efficiency of medical staff. An experimental outdoor work tent was set up and university students were used to study the thermal comfort of personnel wearing protective clothing in hot and humid environments. The experiment was carried out simultaneously through subjective and objective field tests and physiological tests of personnel. The wet bulb globe temperature (WBGT) index was investigated to divide the outdoor thermal environment into four working conditions: 21–23 °C, 23–25 °C, 25–27 °C and 27–29 °C. Under the different thermal environment intensities, the variations of physiological parameters of test personnel were monitored. The results showed that when WBGT was increased to 27–29 °C, 100% of the participants expected the external temperature to become cooler and the humidity to decrease after one hour. When the temperature was close to 30 °C and the relative humidity was close to 60%, it was necessary to take cooling measures to reduce the thermal stress of the participants. Moreover, relationships between subjective feelings and physiological parameters of the nucleic acid sampling personnel were obtained. Results also found that the forehead, chest and back were the highest skin temperature parts, so it is most effective to give priority to improving the thermal comfort of these three locations. As an early attempt to conduct the real outdoor experimental study on the thermal comfort of COVID-19 nucleic acid sampling staff, this study provided a theoretical basis for follow-up research to develop cooling strategies for protective clothing in hot and humid outdoor environments.