Mean Wet Bulb Globe Temperature Research Articles

Climatology of Wet-Bulb Globe Temperature and Associated Heat Waves in the U.S. Great Plains

Abstract Extreme heat such as that seen in the United States and Europe in summer 2022 can have significant impacts on human health and infrastructure. The Occupational Safety and Health Administration (OSHA) and the U.S. Army use wet-bulb globe temperature (WBGT) to quantify the impact of heat on workers and inform decisions on workload. WBGT is a weighted average of air temperature, natural wet-bulb temperature, and black globe temperature. A local hourly, daily, and monthly WBGT climatology will allow those planning outdoor work to minimize the likelihood of heat-related disruptions. In this study, WBGT is calculated from the ERA5 reanalysis and is validated by the Oklahoma Mesonet and found to be adequate. Two common methods of calculating WBGT from meteorological observations are compared. The Liljegren method has a larger diurnal cycle than the Dimiceli method, with a peak WBGT about 1°F higher. The high- and extreme-risk categories in the southern U.S. Great Plains (USGP) have increased from 5 days per year to 15 days from 1960 to 2020. Additionally, the largest increases in WBGT are occurring during DJF, potentially lengthening the warm season in the future. Heat wave definitions based on maximum, minimum, and mean WBGT are used to calculate heat wave characteristics and trends with the largest number of heat waves occurring in the southern USGP. Further, the number of heat waves is generally increasing across the domain. This study shows that heat wave days based on minimum WBGT have increased significantly which could have important impacts on human heat stress recovery.

Occupational Fatigue and Its Relationship with Musculoskeletal Disorders and Heat Stress among the Workers of Summer Crops in Southeast Iran in 2021.

This research aimed to evaluate work fatigue and its relationship with musculoskeletal disorders (MSDs) and heat stress (WBGT) among greenhouse workers in Jiroft County, southeast Iran. This cross-sectional study was carried out between September 2021 and February 2022 among 150 workers in summer crop greenhouses. Data were collected by a demographic questionnaire, the Swedish occupational fatigue inventory (SOFI-20), and the Nordic musculoskeletal questionnaire (NMQ), and wet bulb globe temperature (WBGT) was measured as per ISO 7243. The collected data were analyzed by the χ2 test, logistic regression, and multivariable linear regression in the Stata 17.0 software. The results showed a higher total fatigue score among the studied workers (mean = 100.71 out of 200). Among the fatigue dimensions, the three dimensions of lack of energy, physical discomfort, and physical exertion had the highest scores of 27.28, 26.71, and 25.71, respectively. The highest rate of MSD prevalence was in the back (54.7%), neck (50.7%), and shoulders (49.3%). Based on ISO 7243, the mean WBGT was beyond the allowed level for most tasks for greenhouse workers. There was a statistically significant relationship between occupational fatigue with MSDs and WBGT. Given the relatively high score reported for fatigue and its relationship with MSDs and heat stress, it is recommended to conduct further and more applied studies to investigate the approaches to alleviating heat stress and physical ergonomic risk factors in greenhouses in this occupational group.

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.

Heat Stress Vulnerability Among Small-Scale Factory Workers and Adaptive Strategies in Ahmedabad: a Cross Sectional Study

Introduction: Global warming is likely to affect certain groups such as workers in heat-producing industries. With limited research exploring such an important area, this study aimed to explore the heat stress vulnerability and adaptive strategies of indoor small-scale factory workers. Methods: This was a cross-sectional study and a mixed-method approach was used. The study setting was small-scale factory units. The quantitative component included environmental and biological monitoring from six units of steel rolling mills and foundry in the summer and winter seasons. The study was conducted during the period of November-2018 and May 2019. Heat stress was measured among workers using a portable Wet Bulb Globe Temperature (WBGT) meter. The physiological parameters of workers were also measured. The qualitative component included in-depth interviews of workers and supervisors from eleven units. Results: The maximum temperatures recorded at steel rolling mills and foundry crossed Occupational Safety and Health Administration (OSHA) threshold (27.5℃) in summer as well as winter. The mean WBGT at the steel rolling mill recorded 31.5℃. The physiological measurements of workers also crossed the threshold level for heart rate and oral temperature in steel rolling and foundry units. The units had mechanisms to dissipate heat but lack a temperature monitoring mechanism inside the units. The workers wore lighter or fewer clothes as an adaptive measure but uncomfortable PPEs in foundry units were avoided. Conclusion: Heat stress in small-scale industry units was found high and there is a high need to develop specific strategies for such vulnerably high heat-exposed groups.

Occupational Heat Stress and Kidney Health in Salt Pan Workers

Work in heat affects millions of workers. Although kidney function in agricultural workers is increasingly researched, nonagricultural studies are scarce. In coastal salt pans, the absence of occupational exposures to pesticides and other toxicants allows assessment of heat stress alone. Seven Indian salt pans were surveyed from 2017 to 2020. Job-specific workload was assessed. Heat stress was characterized as exceeding the wet bulb globe temperature (WBGT)-threshold limit value (TLV) for high and moderate workloads. Preshift and postshift heart rates (HRs), tympanic temperatures, and urine specific gravity (USG) were measured for 352 workers, as were sweat rates (SwR), serum creatinine (SCr), serum uric acid, and urine dipstick. Estimated glomerular filtration rate (eGFR; ml/min per 1.73 m2) was computed. Heat-strain symptoms were assessed using questionnaires. The mean WBGT was 30.5 ± 1.3 °C (summer) and 27.8 ± 1.9 °C (winter). Water intake during the workday was low, median was one Litre, and most workers (87%) exceeded the TLV for heat stress. Dehydration-related symptoms were frequent in those with high-heat stress, as were cross-shift increases in temperature (≥1°C; 15%), a high USG (≥1.020; 28%), and a high SwR (≥1 l/h; 53%). An eGFR of 60 to 89 ml/min per 1.73 m2 was observed in 41% of all workers examined, and 7% had eGFR below 60 ml/min per 1.73 m2. The odds ratio for eGFR<90 ml/min per 1.73 m2 in workers exceeding the TLV, compared to workers below this limit, adjusted for age and gender was 2.9 (95% CI: 1.3-6.4). Workplace interventions to prevent heat stress and dehydration in the salt pans and other at-risk industries are urgently required. The findings strengthen the notion that high-heat stress and limited hydration is a risk factor for kidney dysfunction.

Heat Stress and Noise Exposure Levels in a Manufacturing Plant

This paper analyses skilled workers’ heat stress and noise exposure levels at a pressure vessel manufacturing plant. Measurements were conducted at three partially enclosed workspaces of the plant where hot work and metal fabrications were conducted using a multi-function thermal environment data logger and a sound level recorder. A survey was developed to obtain the field workers’ perceptions of their immediate heat and noise environments. The findings suggested that the heat and noise conditions were generally acceptable. The calculated mean Wet-bulb Globe Temperature (WBGT) indicated that there was only minimal risk of heat stress for the workers. It was also identified that the noise intensities in the sections studied were within the permissible exposure limit for an 8-hour duration specified in the Department of Occupational Safety and Health (DOSH) guideline. Besides, questionnaire survey results showed that the thermal and noise conditions at the workplace were acceptable. The workers perceived their work environment as warm with sensible air movement, moderately humid, free from heat and noise-related injuries, and able to have clear conversations with their co-workers while working.

Spatiotemporal changes in Hourly Wet Bulb Globe temperature in Peninsular Malaysia

Global warming causes a temperature rise and alteration of other meteorological variables that directly or indirectly affect human comfort. The wet bulb globe temperature (WBGT) incorporates the effects of multiple meteorological variables to provide a reliable measure of human thermal stress. Despite the large significance of WBGT on public health, studies related to characterization and trends assessment of WBGT are limited in the tropical humid region like Peninsular Malaysia due to the unavailability of all meteorological variables required for such analysis. This study employed reanalysis meteorological data of ERA5 to assess the characteristics and changes in hourly, daily, monthly, seasonal and annual outdoor WBGT over peninsular Malaysia for the period 1959–2021 using the Liljegren method. The WBGT values were classified into five categories to assess the human thermal stress levels defined by the United States Department of the Army (USDA). The mean daily WBGT in PM varies from 21.5 °C in the central south elevated region to 30.5 °C in the western coastal region. It always reaches a heat-related illness risk level (31.20 °C) in the afternoon during monsoon and extreme stress conditions during inter-monsoonal periods. The trend analysis revealed an increase in WBGT for all the time scales. The higher increase in the mean and maximum WBGT was estimated in the coastal and south regions, nearly by 0.10 to 0.25 °C/decade. The increase in mean nighttime WBGT was 0.24 °C/decade, while in mean daytime WBGT was 0.11 °C/decade. The increase in WBGT caused a gradual expansion of areas experiencing daily WBGT exceeding a high-risk level for 5 h (11 AM to 3 PM). The information and maps generated in this study can be used for mitigation planning of heat-related stress risk in PM, where temperature extremes have grown rapidly in recent years.

Using Wet Bulb Globe Temperature and Physiological Equivalent Temperature as Predicative Models of Medical Stress in a Marathon: Analysis of 30 Years of Data From the Twin Cities Marathon.

: Assess the relationships between wet bulb globe temperature (WBGT) and physiologic equivalent temperature (PET) at the start of a northern latitude marathon and their associations with medical stress and transfers to the emergency room (ER) when the race environment is unexpectedly warm, and participants are not acclimatized. : Retrospective review. : Twin Cities Marathon from 1990 to 2019. : Runners competing in the Twin Cities Marathon. : Start WBGT (prospectively collected) and PET (retrospectively calculated). : Marathon race starters and finishers and race day medical data (eg, medical stress, number of medical encounters, and number of ER visits). : The mean WBGT was 7.4°C (range -1.7°C to 22.2°C), and the meant PET was 5.2°C (range -16.7°C to 25.9°C). PET was not determined to be a significant predictor of medical stress (P = 0.71); however, a significant quadratic association between WBGT and medical stress was found (P = 0.006). WBGT (P = 0.002), but not PET (P = 0.07), was a significant predictor of the number of ER visits. Start WBGT was a better predictor of medical stress and ER visits than PET at the Twin Cities Marathon over a 30-year period. The start WBGT may be a better tool to predict race day environment medical safety.

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.

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

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.

The Heat Is On: Observations and Trends of Heat Stress Metrics during Florida Summers

Abstract Extreme heat is annually the deadliest weather hazard in the United States and is strongly amplified by climate change. In Florida, summer heat waves have increased in frequency and duration, exacerbating negative human health impacts on a state with a substantial older population and industries (e.g., agriculture) that require frequent outdoor work. However, the combined impacts of temperature and humidity (heat stress) have not been previously investigated. For eight Florida cities, this study constructs summer climatologies and trend analyses (1950–2020) of two heat stress metrics: heat index (HI) and wet-bulb globe temperature (WBGT). While both incorporate temperature and humidity, WBGT also includes wind and solar radiation and is a more comprehensive measure of heat stress on the human body. With minor exceptions, results show increases in average summer daily maximum, mean, and minimum HI and WBGT throughout Florida. Daily minimum HI and WBGT exhibit statistically significant increases at all eight stations, emphasizing a hazardous rise in nighttime heat stress. Corresponding to other recent studies, HI and WBGT increases are largest in coastal subtropical locations in central and southern Florida (i.e., Daytona Beach, Tampa, Miami, and Key West) but exhibit no conclusive relationship with urbanization changes. Danger (103°–124°F; 39.4°–51.1°C) HI and high (&gt;88°F; 31.1°C) WBGT summer days exhibit significant frequency increases across the state. Especially at coastal locations in the Florida Peninsula and Keys, danger HI and high WBGT days now account for &gt;20% of total summer days, emphasizing a substantial escalation in heat stress, particularly since 2000. Significance Statement Extreme heat is the deadliest U.S. weather hazard. Although Florida is known for its warm and humid climate, it is not immune from heat stress (combined temperature and humidity) impacts on human health, particularly given its older population and prevalence of outdoor (e.g., agriculture) work. We analyze summer trends in two heat stress metrics at eight Florida cities since 1950. Results show that heat stress is increasing significantly, particularly at coastal locations in central and southern Florida and at night. The number of dangerous heat stress days per summer is also increasing across Florida, especially since 2000. Our analysis emphasizes that despite some acclimation, Florida is still susceptible to a serious escalation in extreme heat as the climate warms.

Identifying the need for locally-observed wet bulb globe temperature across outdoor athletic venues for current and future climates in a desert environment

Exertional heat illness and stroke are serious concerns across youth and college sports programs. While some teams and governing bodies have adopted the wet bulb globe temperature (WBGT), few practitioners use measurements on the field of play; rather, they often rely on regionally modeled or estimated WBGT. However, urban development-induced heat and projected climate change increase exposure to heat. We examined WBGT levels between various athletic surfaces and regional weather stations under current and projected climates and in hot-humid and hot-dry weather regimes in the southwest U.S. in Tempe, Arizona. On-site sun-exposed WBGT data across five days (07:00–19:00 local time) in June (dry) and August (humid) were collected over five athletic surfaces: rubber, artificial turf, clay, grass, and asphalt. Weather station data were used to estimate regional WBGT (via the Liljegren model) and compared to on-site, observed WBGT. Finally, projected changes to WBGT were modeled under mid-century and late-century conditions. On-field WBGT observations were, on average, significantly higher than WBGT estimated from regional weather stations by 2.4 °C–2.5 °C, with mean on-field WBGT across both months of 28.5 ± 2.76 °C (versus 25.8 ± 3.21 °C regionally). However, between-athletic surface WBGT differences were largely insignificant. Significantly higher mean WBGTs occurred in August (30.1 ± 2.35 °C) versus June (26.9 ± 2.19 °C) across all venues; August conditions reached ‘limit activity’ or ‘cancellation’ thresholds for 6–8 h and 2–4 h of the day, respectively, for all sports venues. Climate projections show increased WBGTs across measurement locations, dependent on projection and period, with average August WBGT under the highest representative concentration pathway causing all-day activity cancellations. Practitioners are encouraged to use WBGT devices within the vicinity of the fields of play, yet should not rely on regional weather station estimations without corrections used. Heat concerns are expected to increase in the future, underlining the need for athlete monitoring, local cooling design strategies, and heat adaptation for safety.

Indoor Comfort, Thermal Indices, and Energy Assessment of Multi-Family Colonial Revival Style Buildings

Colonial Revival style residences have unique architectural features amongst others. They are common multi-family residences in the United States with no or limited information about their performance. The research purpose is to assess indoor comfort, energy performance, and thermal indices in multi-family Colonial Revival style residences. The research questions include (i) Do Colonial Revival style buildings perform better than other old buildings? (ii) Do the buildings consume additional electricity than typical and other old buildings? The research examined four case studies in Hartford County, Connecticut. The investigation explored comfort surveys, monitoring, collection of actual electricity usage, and assessed thermal indices using mathematical models. The average indoor temperature of 25.4 °C and relative humidity (RH) of 61.3% are reported. About 67% of the residents are thermally comfortable. The research noted significance between thermal sensation and other variables, excluding how occupants feel about the air movement. The average number of hours of temperature exceeds 28.0 °C and 30.0 °C marks for over 11.4% and 2.5% of the time, respectively, except in one of the buildings. The mean indoor temperatures are within the applicable bands of the adaptive comfort models. The averages of actual thermal sensation vote (TSV) ranged from 3.32 to 4.37 on a 7-point sensation scale. The mean neutral temperatures varied from 24.2–25.6 °C. The average monthly electricity bill is within the national average for residences in summer, excluding in August. The mean wet-bulb globe temperature (WBGT) of 21.1–22.3 °C and summer simmer index (SSI) of 30.1–32.4 °C are calculated as feasible bands for thermal indices in the buildings. The basements are more comfortable than other spaces within the case studies. The research outcomes can be used for future developments of Colonial Revival style and other similar buildings. The study recommends interventions such as retrofit to improve the performance of some existing Colonial Revival style buildings, especially the older ones that are less insulated with outdated equipment and appliances.

A new evaluation index for indoor hot environment in naturally ventilated building with hot surface

Indoor wet-bulb globe temperature (WBGT) was extensively used to evaluate the indoor hot environment in a naturally ventilated building, but it does not consider the effect of air movement caused by the hot surface. A potential evaluation index, which is a difference between the mean radiant temperature and the air temperature (Δtr–a), was introduced to be integrated with the indoor WBGT to evaluate the indoor hot environment with hot surface. Subjective evaluation of the occupant's thermal perceptions and objective measurement of indoor physical parameters were carried out in a typical naturally ventilated room with hot surface ranged from 50°C to 250°C. The results show that the indoor air temperature, mean radiant temperature and WBGT were increased by 8.6°C–12.9°C, 11.2°C–29.7°C and 4.7°C–7.5°C, respectively, with participant's light activity, and by 9.9°C–13.5°C, 14.9°C–29.4°C and 5.7°C–8.0°C, respectively, with participant's heavy activity. Indoor air temperature was increased linearly with the indoor WBGT, whereas the mean radiant temperature was increased non-linearly with the indoor WBGT. Besides, the non-linear relationship between the occupant's thermal perceptions and Δtr−a coincided very well with those between occupant's thermal perceptions and indoor WBGT. This suggests that the Δtr–a may be a potential index to be integrated with the indoor WBGT for evaluating the indoor hot environment in naturally ventilated building with hot surface.

From theory to practice: operationalizing a climate vulnerability for sport organizations framework for heat hazards among US High schools

BackgroundSport organizations must comprehensively assess the degree to which their athletes are susceptible to exertional heat illnesses (i.e. vulnerable) to appropriately plan and adapt for heat-related hazards. Yet, no heat vulnerability framework has been applied in practice to guide decision making. ObjectivesWe quantify heat vulnerability of state-level requirements for health and safety standards affecting United States (US) high school athletes as a case study. DesignObservational. MethodsWe utilize a newly developed climate vulnerability to sports organizations framework (CVSO), which considers the heat hazard of each state using summer maximum wet bulb globe temperature (WBGT) in combination with an 18-point heat safety scoring system (18 = best policy). Heat vulnerability is categorized as “problem” [higher heat (>27.9°C) and lower policy score (≤9)], “fortified” [higher heat (>27.9°C) and higher policy score (>9)], “responsive” [lower heat (<27.9°C) and lower policy score (≤9)], and “proactive” [lower heat (<27.9°C) and higher policy score (>9)]. ResultsAcross the US, the mean WBGT was 28.4±2.4°C and policy score was 6.9±4.7. In combination, we observed organizations within each of the four vulnerability categories with 16% (n=8) in fortified, 16% (n=8) in proactive, 29% (n=15) in problem, and 39% (n=20) in responsive. ConclusionsThe CSVO framework allowed us to identify different degrees of vulnerability among the state’s and to highlight the 29% (n=15) of states with immediate needs for policy revisions. We found the CSVO framework to be highly adaptable in our application, suggesting feasibility for use with other sports governing bodies.

Wet bulb globe temperatures and risk of acute kidney injury among Central American workers

Background/Aim: There is an epidemic in Central America of chronic kidney disease of unknown etiology (CKDu), also referred to as Mesoamerican Nephropathy (MeN). MeN prevalence is high among agricultural workers and other occupations involving physical labor in hot working environments, such as brickmaking. Chronic heat stress and volume depletion are hypothesized to be important risk factors. Methods: The MesoAmerican Nephropathy Occupational Study (MANOS) is a prospective cohort study of 569 Salvadoran and Nicaraguan workers designed to investigate environmental and occupational risk factors for MeN. MANOS participants represent five industries: sugarcane, corn, plantain, brick manufacturing, and construction. At baseline, workers were monitored for three consecutive work days. Wet bulb globe temperature (WBGT) was collected every minute during these work shifts using wet bulb globe thermometers. Participants provided serum samples pre- and post-shift on the third day of baseline monitoring. Results: At baseline, the mean estimated glomerular filtration rate (eGFR) of MANOS participants was 106.7 mL/min/1.73 m2. Fifty three (9.3%) had an eGFR &lt; 60 mL/min/1.73 m2. Fourteen participants met serum creatinine-based criteria for cross-shift acute kidney injury (AKI) during baseline monitoring. The mean percent increase in serum creatinine across work shifts was 5.3%. In El Salvador, WBGT was measured on forty-six separate days of workplace monitoring. On these days, an average of 54.7% of the work shift temperatures monitored after 6am were above 28°C, the American Conference of Governmental Industrial Hygienists Threshold Limit Value for moderate work at a continuous work rate. In unadjusted analyses, mean WBGT temperature on the third day of monitoring was positively associated with percent increase in serum creatinine (1.3% increase per 1°C) among Salvadoran workers. Conclusions: MANOS participants experience workplace temperatures that regularly exceed health-protective guidelines. Exposures to these high temperatures may increase the risk of AKI among these workers.

Body Mass And Urinary Hydration Measures During Preseason High School Football Practices In The Heat

Hydration assessment is an important measure to help reduce the risk of exertional heat illness. Maintaining adequate hydration can be problematic for football players practicing in the heat on consecutive days. PURPOSE: To examine day to day differences and the relationships between urinary markers of urine color (Ucol) and urine specific gravity (USG), and percent body mass loss (%BML) during football practices in the heat. METHODS: Thirty-one male high school football players (16 ± 1 years; 181.2 ± 12.0 cm; 68.1 ± 5.4 kg; BMI: 20.8 ± 1.8 km/m2) volunteered to participate in this study. Before and after each practice, players were weighed (in shorts) and provided a urine sample. Urine was assessed for Ucol and USG and was assessed by the same person. Correlations assessed relationships, while t-tests assessed differences between both pre-post differences and subsequent days. P value was significant at P<.05. RESULTS: Mean wet-bulb globe temperature across 8 practices was 30.6 ± 2.5oC. There were significant correlations between pre-Ucol and pre-USG (r = 0.73, p=0.00, n = 209) and post-Ucol and post-USG (r = 0.66, p = 0.00, n = 209). Post-Ucol (5 ± 1) was significantly greater than pre-Ucol (4 ± 2; p = 0.00). Post-USG (1.022 ± 0.008) was significantly greater than pre-USG (1.020 ± 0.008; p = 0.00). Post body mass measures were significantly lower than pre-body mass resulting in 0.9 ± 1.1%BML. Post-practice body mass and USG were not significantly different from the next day’s pre-practice measures (p > 0.05); however, post-Ucol was significantly higher (5 ± 2) compared to the next day’s pre-practice Ucol (4 ± 1; p = 0.000). CONCLUSION: Although the football players’ body mass measures were similar on subsequent days, their Ucol was lighter before the next day’s practice. We also found a strong relationship between Ucol and USG, suggesting Ucol is an acceptable hydration measure where USG is not feasible in field settings. Due to individual variability in these hydration measures, clinicians should provide individualized recommendations to ensure adequate hydration during practices in the heat as well as from one day to the next. This study was fully funded by the National Athletic Trainers’ Association Research & Education Foundation.

Rapid Warming in Summer Wet Bulb Globe Temperature in China with Human-Induced Climate Change

AbstractOn the basis of a newly developed observational dataset and a suite of climate model simulations, we evaluate changes in summer mean wet bulb globe temperature (WBGT) in China from 1961 through 2080. We show that summer mean WBGT has increased almost everywhere across China since 1961 as a result of human-induced climate change. Consequently, hot summers as measured by summer mean WBGT are becoming more frequent and more conducive to heat stress. Hot summers like the hottest on record during 1961–2015 in western or eastern China are now expected occur once every 3–4 years. These hot WBGT summers have become more than 140 times as likely in eastern China in the present decade (2010s) as in the 1961–90 baseline period and more than 1000 times as likely in western China. The substantially larger influence in western China is associated with its stronger warming signal, which is likely due to the high Bowen ratio of sensible to latent heat fluxes of dry soils and increases in absorbed solar radiation from the decline in mountain snow cover extent. Observation-constrained projections of future summer mean WBGT under the RCP8.5 emissions scenario indicate that, by the 2040s, almost every summer in China will be at least as hot as the hottest summer in the historical record, and by the 2060s it will be common (on average, every other year) for summers to be as much as 3.0°C hotter than the historical record, pointing to potentially large increases in the likelihood of human heat stress and to a massive adaption challenge.