Wet Bulb Globe Temperature Index Research Articles

Assessing the impact of green infrastructure on thermal comfort in relation to humidity: A case study in Korea

Problems arising from heatwaves and urban heat islands (UHIs) exacerbated by climate change have prompted diverse adaptation strategies. Although green infrastructure, which positively affects climate change adaptation, has been extensively evaluated, global-scale assessments of UHIs indicate that green infrastructure may not be sufficient to mitigate UHIs in humid regions with annual precipitation exceeding 1000 mm or summer precipitation exceeding 570 mm. However, these assessments primarily focused on UHIs; different results may be obtained for individual heat comfort. As relative humidity increases, the cooling effect of green areas potentially decreases. This suggests the need for additional studies on the impact of short-term precipitation, which increases relative humidity and induces cooling effects on green infrastructure. Korea experiences a humid summer due to the concentration of precipitation (approximately 711 mm of summer precipitation); thus, the contribution of green infrastructure to improving heat comfort might be limited. Therefore, this study investigated the impact of green infrastructure on thermal comfort in relation to precipitation levels using the Wet-Bulb Globe Temperature (WBGT) index and data from weather stations in Korea. Precipitation intensity was categorized into 2-day periods and 10 mm/day. Subsequently, thermal comfort was compared for summers from 1993 to 2022 according to the green infrastructure ratio around the stations. The results indicated that green infrastructure had a cooling effect on clear days but only had a cooling effect on precipitation days when the level of green infrastructure was above the critical ratio. Additionally, green infrastructure reduced the WBGT index if minimal precipitation occurred during the five-day cooling period following precipitation. While green infrastructure remains crucial for climate change adaptation, other strategies must be implemented to improve the thermal environment, particularly in areas with frequent precipitation.

Validation of a temperature-humidity index (Humidex) in evaluating heat stress at a tile factory in Iran.

Several heat indices have been developed in industrial health, but each has its limitations. The objective of this article is to determine the validity and applicability of a temperature-humidity index, named Humidex compared with the Standard Wet-Bulb Globe Temperature (WBGT) index (ISO 7243). This cross-sectional study was conducted in the summer of 2019, in a tile factory in the west of Iran. 59 measurements were performed in 8 different workstations. Environmental parameters including natural wet bulb temperature (Tnw), dry bulb temperature (Ta), globe bulb temperature (Tg), and heat stress (WBGT) were measured. Humidex was calculated according to an equation. SPSS software (version 16) was used for data analysis. There was a high correlation between Humidex and WBGT in the estimation of heat stress (R=0.912, P<0.001). The Kappa Coefficient between Humidex and WBGT was 0.298, P=0.001. Humidex is highly correlated with WBGT. Humidex can be used instead of the WBGT index, especially in hot and humid environments.

A scoping review on heat indices used to measure the effects of heat on maternal and perinatal health

A previous systematic review has shown associations between exposure to high temperatures and negative birth outcomes. To date, a scoping review for heat indices and their use to measure effects...

Numerical simulation integrating passive cooling strategies for building thermal comfort in Guinea's climates

ABSTRACT Due to the increased demand for indoor air conditioning, the residential sector in tropical regions is becoming more and more energy intensive. In this study, several passive cooling strategies in the building sector in Guinea, such as natural ventilation, thermal insulation, and cool coating roof, as well as the coupling between these different solutions, have been evaluated. Therefore, the thermal behaviour of a residential building in two climatic zones of Guinea is evaluated. The building thermal discomfort is assessed by the adaptive and conventional approaches, as well as the Wet Bulb Globe Temperature (WBGT) thermal stress indicators and the PMV-PPD indices. The results show that high levels of discomfort and thermal stress are present in the reference building. The use of the combination of passive cooling strategies allowed a reduction of the thermal discomfort evaluated by an adaptive approach of 74% in Conakry and 65% in Kankan. The WBGT index was improved by 42% in Conakry and 45% in Kankan. The operative temperature also decreased to 4.4°C for Conakry and 3.61°C for Kankan.

The influence of humid heat on morbidity of megacity Shanghai in China

BackgroundIncreased attention has been paid to humid-heat extremes as they are projected to increase in both frequency and intensity. However, it remains unclear how compound extremes of heat and humidity affects morbidity when the climate is projected to continue warming in the future, in particular for a megacity with a large population. MethodsWe chose the Wet-Bulb Globe Temperature (WBGT) index as the metric to characterize the humid-heat exposure. The historical associations between daily outpatient visits and daily mean WBGT was established using a Distributed Lag Non-linear Model (DLNM) during the warm season (June to September) from 2013 to 2015 in Shanghai, a prominent megacity of China. Future morbidity burden related to the combined effect of high temperature and humidity were projected under four greenhouse gases (GHGs) emission scenarios (SSP126, SSP245, SSP370 and SSP585). ResultsThe humid-heat weather was significantly associated with a higher risk of outpatient visits in Shanghai than the high-temperature conditions. Relative to the baseline period (2010–2019), the morbidity burden due to humid-heat weather was projected to increase 4.4 % (95 % confidence interval (CI): 1.1 %–10.1 %) even under the strict emission control scenario (SSP126) by 2100. Under the high-GHGs emission scenario (SSP585), this burden was projected to be 25.4 % (95 % CI: 15.8 %–38.4 %), which is 10.1 % (95 % CI: 6.5 %–15.8 %) more than that due to high-temperature weather. Our results also indicate that humid-hot nights could cause large morbidity risks under high-GHGs emission scenarios particularly in heat-sensible diseases such as the respiratory and cardiovascular disease by the end of this century. ConclusionsHumid heat exposures significantly increased the all-cause morbidity risk in the megacity Shanghai, especially in humid-hot nights. Our findings suggest that the combined effect of elevated temperature and humidity is projected to have more substantial impact on health compared to high temperature alone in a warming climate.

Observed Warming Trends at U.S. Army Basic Combat Training Installations andImplications forFuture Recruit Training.

Army recruits conducting BCT are among the most susceptible population of military personnel to experience exertional heat illness, a concern expected to become increasingly urgent due to steadily rising temperatures. In this study, we provide an empirical analysis of wet bulb globe temperature (WBGT) index trends at U.S. Army BCT installations and quantify the magnitude of these trends. Assuming these warming trends continue, the anticipated effects of increasing temperature trends are discussed in relation to potential impacts on recruit heat illness incidence and training disruption. We obtained weather data beginning in the early 1960s, including WBGT index measurements derived by the U.S. Air Force 14th Weather Squadron. We apply these datasets to two classifications for high WBGT index days, including one classification accounting for heat illness susceptibility based on prior day heat exposure, to determine when recruits are most at risk of heat illness. The daily likelihood of extreme WBGT index values is described at each installation using a 30-year climatological average. Trends in the WBGT index are evaluated quantitatively during the warm season (May 1-September 30) and full year and compared between decades and by individual BCT classes. Trends in the WBGT index have increased at all four BCT installations. Between January 1960 and October 2022, the mean WBGT index value increased most quickly at Ft Jackson, SC (0.272°C decade-1, CI: 0.255-0.289) and least at Ft Moore, GA (0.190°C decade-1, CI: 0.170-0.210). Ft Moore experiences the greatest heat burden, with the daily likelihood of experiencing a "black flag" event (≥90°F WBGT index) peaking at nearly 50% in late July, while Ft Leonard Wood, MO, experiences the least heat burden. This heat burden is spread unevenly across installations and dependent on BCT class start date. Recruits beginning in mid-June will experience approximately 200 hours of hazardous heat during BCT at Ft Moore, GA; 100 hours at Ft Jackson, SC; 80 hours at Ft Sill, OK; and 61 hours at Ft Leonard Wood, MO. Temperatures measured on the WBGT index have steadily increased at US Army basic training installations since at least 1960. In the future, adaptation to the BCT program will be required to maintain rigorous standards without incurring unacceptable risk of recruit heat illness. The analysis provided by this study can help inform medical, training, and policy implementations needed to ensure continued BCT in a warming world.

Investigation of Heat Stress among Greenhouse Workers in Chhattisgarh, India

Greenhouse cultivation is spreading as it offers the grower a higher net yield per hectare from high quality crops as it reduces the likelihood of yield decline. The greenhouse is kept at 30-40˚ C with a relative humidity of up to 70%, which could be ideal for plant growth, but is not suitable for workers. Heat exposure in the workplace causes discomfort to the human while working.   So, the main goal of conducting this research is to address the extent of heat stress and associated health issues for the greenhouse workers. The study was planned for 2022 in the Raipur district of Chhattisgarh. Prior to the assessment, a questionnaire survey was conducted among 50 greenhouse workers to learn perceptions of heat exposure, heat-related health issues and awareness of heat management. To get the heat exposure air temperature, wet bulb temperature, relative humidity, black globe temperature were measured on hourly basis. The wet bulb globe temperature (WBGT) was measured along with greenhouse workers' physiological parameters to quantify heat exposure. With the help of clock diagram showing Humidex Index (HI). The time period at which farmers most likely to suffer from heat stress was estimated. It was reported that in April, May, June, July, August and September WBGT index reaches varied between 30 and 34°C. According to ISO 7243 the recommended WBGT for comfortable workplace should be less than  31°C. Further study was conducted to get physiological responses of the 21 farm workers in three different type of greenhouses and at three time slots. It resulted that heart rate was maximum i.e. 156 bpm in walk in tunnel at 11 am to 1 pm. The average working heart rate was 20 % more than the open field condition. Hence, the study will help to make the strategies to reduce the exposure of heat stress conditions to the greenhouse workers.

The effects of climate change on the health and safety of pasta industry workers: assessment of heat stress using wbgt index

Protection of workers from environmental heat stress, especially the risks to which individuals are exposed due to the microclimatic conditions of the summer season characterized by particularly high temperatures, requires a careful assessment of working conditions and the implementation of preventive actions. The sectors most affected by such exposure are related to construction and road works, agriculture, and maritime fishing. This contribution presents the practical assessment and study of some work environments belonging to the pasta production sector, focusing on thermal stress in hot working environments, based on the use of the Wet Bulb Globe Temperature (WBGT) index, easily determinable with the use of simple portable instruments. The impact of climate change on the health and safety of workers in the pasta sector is a topic of growing importance. Climate variations adversely affect the health of workers throughout the entire pasta supply chain. This article explores the tangible effects of global warming on the well-being of sector workers, with a particular focus on heat stress and its related impact on productivity. The challenges faced by workers in the pasta sector due to extreme heat weather conditions and appropriate strategies aimed at mitigating the associated economic impacts were analyzed. Furthermore, precautionary measures were examined to define, prevent, and protect the health and safety of workers, thereby contributing to the long-term sustainability of this vital food industry. This case study delves into the analysis of temperatures in the workplaces of three pasta factories during two distinct periods of the year, using the WBGT index. This index provides a more accurate assessment of the thermal conditions perceived by workers, considering the complexity of the variables involved. The decision to examine three different pasta factories aims to provide a comparative analysis of the thermal conditions, taking into account the specificities of each structure. The chosen investigation period, spanning summer and early autumn, is motivated by the desire to understand seasonal variations and evaluate the impact of climate change on microclimatic conditions in workplaces. The main objective of the study was toidentify any significant differences in thermal conditions between the two periods considered and to analyze how climate change could influence workers’ health.The comparative analysis of the data collected during the months of July and October aims to provide a detailed overview of the thermal conditions in pasta factories, highlighting any trends or fluctuations. Through this investigation, we aimed to outline the potential impacts of climate change on the microclimate of workplaces, contributing to greater awareness and the formulation of adaptation strategies. The information emerging from this study is useful for managing the safety and well-being of workers in the specific pasta factories examined. However, it could also constitute a broader contribution in the context of discussions related to the adaptation of working conditions to climate change. The ultimate objective was to promote safe, comfortable, and resilient working environments capable of facing the challenges imposed by climate variations.

Effects of cooling roofs on mitigating the urban heat island and human thermal stress in the Pearl River Delta, China

The Weather Research and Forecasting model was employed to simulate the effects of cooling roofs on the urban heat island effect and human thermal stress in the Pearl River Delta region, China, in summer (June–August) 2014. It was found that cooling roofs can reduce the 2-m air and ground-surface temperature, wind speed, and planetary boundary layer height, while increasing the specific and relative humidity, in urban areas. The effects can influence the entire urban boundary layer, especially in commercial/industrial areas in the daytime. Cooling roofs can effectively mitigate the urban heat island effect, and the mitigation of white roofs is more significant than that of green roofs. The mitigation of the urban heat island effect is stronger in commercial/industrial areas than in low-intensity residential areas. The city-wide 2-m and ground-surface urban heat island intensity induced by white roofs can reduce by 1.5 °C and 4.8 °C at noon, while the corresponding decreases induced by green roofs can reach 0.7 °C and 1.9 °C, respectively. White roofs improve human thermal comfort both in the daytime and at nighttime. With white roofs, three city-wide thermal-stress indices (wet-bulb globe temperature, apparent temperature, and humidity index) can be reduced at noon by 0.8 °C, 1.3 °C and 1.5 °C, respectively. Green roofs mostly improve human thermal comfort at nighttime but even deteriorate it in the daytime. The above three indices decrease by less than 0.5 °C in different urban categories at nighttime with green roofs.

The Effects Of Heat Stress On Haematological Parameters In Production Department Of Food Industry Employees.

To investigate the effects of heat stress on some haematological parameters among food industry employees working in the production department. The ambispective, single-centre, case-control study was conducted from December 1, 2016, to June 6, 2018, at Istanbul Gedik University and the Okan University, Istanbul, which is part of the Marmara region of Turkey. The study comprised subjects of either gender aged 22-57 years. Those working in the food industry were the cases in group A, while healthy controls formed group B. Within group A, subjects who were office workers formed subgroup A1, while those in the production department working in the heat treatment areas exposed to high temperatures formed subgroup A2. Heat stress in the environment was evaluated using the Wet Bulb Globe Temperature index. Peripheral blood haemoglobin and platelet levels, neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were compared between the cases and the controls. Data was analysed using SPSS 22. Of the 257 subjects, 139(54.1%) were women and 118 (45.9%) were men. The overall mean age was 35.07±7.32 years. There were 143(55.6%) subjects in group A and 114(44.4%) in group B. Within group A, 19(13.3%) subjects were in subgroup A1 and 124(86.7%) in subgroup A2. The mean working duration for group A was 9.95±4.37 years (range 5-24 years). Haemoglobin and platelet levels were significantly lower and the neutrophil- lymphocyte ratio was significantly higher in subgroup A2 compared to those in subgroup A1 and group B (p<0.05). There was no significant difference in terms of platelet-lymphocyte ratio (p=0.486). Differences in haematological parameters were significantly different in individuals who worked in the production department and were exposed to heat stress compared to those who did not.

Change of Seasons: Boston Marathon Wet Bulb Globe Temperature Index in October

The importance of providing wet bulb globe temperature (WBGT) heat stress flag category measurements in real time is well recognized by road race directors, and it is bound to become even more important with the rise of extreme weather and pandemic outbreaks. The purpose of this paper is to describe the WBGT index and its components measured during the 125th running of the Boston Marathon on October 11, 2021, for qualitative comparison to measurements made similarly on its traditional April date, 2014 to 2019. Monitoring occurred at the 7 km, 18 km, and 32 km marks of the race in the towns of Ashland, Natick-Wellesley, and Newton. The outdoor WBGT index was calculated from direct hourly measurements of the dry bulb, black globe, and natural wet bulb temperatures from 0900 to 1500 h. The WBGT index was not different among towns; thus, the average hourly values for the 3towns were compared to historical data averaged identically. Although the black globe temperature fluctuated considerably in response to changing cloud cover, on average, partly cloudy skies kept the solar load comparable to what has been observed in April. Dry bulb and wet bulb temperatures were higher than those on most April dates shown, which resulted in a yellow (or amber) flag day for most of the race. The historic October Boston Marathon was among the warmest in recent history. Like the impact of COVID-19 on the 2021 Boston Marathon, future climate challenges around outdoor activities could necessitate rescheduling; they underscore the importance of real-time WBGT index measures.

The Burdens of Occupational Heat Exposure-related Symptoms and Contributing Factors Among Workers in Sugarcane Factories in Ethiopia: Heat Stress Wet Bulb Globe Temperature Meter

BackgroundHeat stress is a harmful physical hazard in many occupational settings. However, consequences of occupational heat exposure among workers in a sugarcane factory in Ethiopia are not well characterized. This study aimed to assess the level of occupational heat exposure-related symptoms and contributing factors. MethodsIn this cross-sectional study, five workstations were selected for temperature measurement. Heat stress levels were measured using a wet-bulb globe temperature index meter. A stratified random sampling technique was used to select 1,524 participants. Heat-related symptoms were assessed using validated questionnaires. ResultsThe level of occupational heat exposure was 72.4% (95% CI: 70.2%–74.8%), while 71.6% (95% CI: 69.3%–74.9%) of participants experienced at least one symptom related to heat stress. The most common heat-related symptoms were swelling of hands and feet (78%), severe thirst (77.8%) and dry mouth (77.4%). The identified risk factors were a lack of reflective shields (AOR: 2.20, 95% CI: 1.53, 3.17), not-enclosed extreme heat sources (AOR: 1.76, 95% CI: 1.23, 2.51), a lack of access to shade (AOR: 9.62, 95% CI: 6.20, 14.92), and inappropriate protective clothing provision (AOR: 1.58, 95% CI: 1.27, 2.71). ConclusionsThe burden of occupational heat exposure and heat-induced symptoms was high. Lack of reflective shields, the absence of enclosed extreme heat sources, a lack of access to shade, and inappropriate protective clothing provision were considerable attributes of heat stress. Therefore, the use of mechanical solutions to stop heat emissions at their sources and the key factors identified were areas for future intervention.

A new method for evaluating the synergistic effect of urban water body and vegetation in the summer outdoor thermal environment

In the context of climate change, urban blue-green infrastructure (UBGI), consisting of water and vegetation, has received extensive attention for urban microclimate improvement. However, the detailed quantification of spatial relationships between blue and green infrastructure elements has not been conducted about the thermal environment. To study the synergistic effect of water and vegetation, this paper conducted the field measurement and questionnaire on typical UBGI in Tianjin, China. The spatial characteristics and the current situation of the thermal environment of UBGI were obtained, and the thermal demands of UBGI users were established based on the wet-bulb globe temperature (WBGT) and heat index (HI). The results of the study indicated that the synergistic effect of the water body and vegetation was the most significant at a distance of 6 m from the water body. In the condition of light airflow (wind speed ≤1.5 m/s), the different orientations relative to the water body had no significant difference in the thermal environment. Based on the quantification of spatial relationships, the conversion factors (cT and cRH) of the synergistic effect at different locations in UBGI were obtained. Furthermore, synergistic effect (SE) models of the thermal environment of UBGI were established according to the conversion factors. Meanwhile, the thermal comfort benchmarks for SE models were quantified (WBGT: 25.76–27.96 °C and HI: 24.98–27.25 °C). This study provides scientific guidance and reference for the planning and redevelopment of UBGI.

Analysis of Urban Heat Island Effect, Heat Stress and Public Health in Colombo, Sri Lanka and Shenzhen, China

Human health, energy and comfort are determined by the climate that remains in the physical environment. Regarding urban climate, few studies assess the urban heat island effect, heat stress, and public health as geographical representations. This study seeks to fill this gap by selecting Colombo, Sri Lanka, and Shenzhen, China, comparatively, two coastal cities with different climate conditions. We quantified and compared the effects of heat waves and their impacts on public health and the effect of urbanization on urban heat islands (UHI). Heat-related public health issues have been calculated using the Wet-Bulb Globe Temperature (WBGT) index. The Urban Heat Island (UHI) effect was analyzed using Land Surface Temperature (LST), created based on Landsat images obtained in 1997, 2009 and 2019. A rapid increase in temperature and humidity creates an uncomfortable environment in both cities, but apparent differences can be observed in climatic phenomena. During the summer (June to August), the prevailing atmospheric condition in Shenzhen makes a “Very severe stress” with Heatstroke highly likely. Nevertheless, seven months (November to April) are found as “Comfortable” without having any heat-related health injuries. However, Colombo has never been classified as “Comfortable” throughout the year. Out of twelve, five months (April to August) are found as “Very severe stress” with Heatstroke highly likely. When considering the urban expansion and UHI, a fast expansion can be observed in Colombo than in Shenzhen. Consequently, with the more severe heat-related public health and rapid urban heat island expansion, Colombo makes it more stressful than Shenzhen city. Our findings highlight the comparison between heat-related public health and urban heat island between two coastal cities with different climate conditions and under rapid urbanization processes. Therefore, it is imperative to assess these risks and respond effectively.

The effect of evaporative cooling vests on the physiological and perceptual strain indices of construction workers

Aim: One of the most harmful agents in construction sites is heat exposure. The aim of this study was to evaluate the performance of new evaporative cooling vests in construction workers. Materials and Methods: This case–control study was implemented on 60 construction workers in hot conditions (air temperature 49.0°, relative humidity 5.5%) in the summer of 2019. In this study, 30 people with cooling vests (case group) and 30 people without cooling vests (control group) were working for 120 min in a hot environment. In both groups, heart rate oral temperature and wet bulb globe temperature (WBGT) index were measured. Moreover, the Perceptual Strain Index (PeSI) and Heat Strain Score Index (HSSI) questionnaires were completed by the workers. Data were analyzed after inter to SPSS16 software. Results: All of the WBGT values were higher than occupational exposure limit. The mean and standard deviation (SD) of the work heart rate in the case and control groups, was equal to 111.1 ± 7.6 beats per minute (bpm) and 114.3 ± 7.9 bpm respectively (P < 0.05). Also the average and SD of the oral temperature in the case and control groups, respectively, was equal to 36.36 ± 0.41 and 36.37 ± 0.55. There was no statistically significant difference. Mean and SD of Physiological Strain Index (PSI), in case and control groups, were 2.53 ± 0.66 and 3.64 ± 0.81, respectively. The mean and SD of the PeSI and the HSSI in the case group were 4.64 ± 0.79 and 10.12 ± 1.71, respectively, and in the control group, 6.41 ± 0.85 and 15.88 ± 0.1.43. Statistically, the difference between PSI, PeSI, and HSSI means was significant. Conclusions: This study results showed that hot environmental conditions were stressful for construction workers and also Iranian evaporative cooling vests (Hifitcool brand) were able to reduce perceptual and physiological heat strain in construction workers in the hot conditions.

Integrating AI and Environmental Analytics for Enhanced Productivity and Safety

In the modern workplace, managing outdoor work schedules has become increasingly challenging due to unpredictable weather conditions. This paper presents an innovative solution that combines real-time weather forecasts with Artificial Intelligence (AI) to create adaptive work schedules. By integrating data from reliable weather sources and analyzing it using machine learning models, we can predict the optimal times for outdoor work, reducing health risks and enhancing productivity. Additionally, we explore the use of the Wet Bulb Globe Temperature (WBGT) index to assess the risk of heat stress and adjust work hours accordingly. Our approach incorporates a dynamic scheduling algorithm that considers factors such as legal work hour limits and the intensity of physical labor. The result is a flexible, AI-powered system that not only ensures worker safety in the face of heat stress but also helps organizations navigate the complexities of climate impact on workforce management. Through this study, our goal is to demonstrate how technology can be leveraged to support a safer and more efficient working environment.

Modeling and predicting trends of heat stress based on climate change phenomenon: A case study in a semi-arid climate

Background: Climate change is one of the most complex human challenges in the future. One of the consequences of climate change is the exposure of people to heat stress, especially in the outdoor environments. The aim of this study was to model the changes in the trend of exposure to heat stress in outdoor environments in the coming decades in the context of climate change and global warming. Methods: The Wet Bulb Globe Temperature (WBGT) index, Canadian Earth System Model (CanESM2), and the Statistical Down Scaling Model (SDSM) were used in a semi-arid climate. In this study, Arak station was considered as a representative of Iran’s semi-arid climate. In this research, the daily data of the minimum and maximum temperatures, humidity, and WBGT index were used from 2011 to 2099. Results: The minimum and maximum air temperatures in the study station show an increasing trend in three time periods. Also, based on the three studied scenarios, air temperature and WBGT index have an upward and positive trend and relative humidity has a downward and negative trend in the coming decades. Conclusion: In general, increasing the exposure of people to heat stress at the study station in the coming decades and based on the simulations of atmospheric general circulation models (GCMs), will not be unexpected.

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