1,073 results on '"Wet-bulb globe temperature"'
Search Results
2. Using wet-bulb globe temperature meters to examine the effect of heat on various tennis court surfaces.
- Author
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Yamaguchi, Hiroki, Mori, Takaaki, Hanano, Hiromi, Oishi, Kan, Ikeue, Kentaro, Yamamoto, Yuiko, and Ishii, Kojiro
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TENNIS courts , *HEAT stroke , *METEOROLOGICAL stations , *ATHLETIC associations , *TEMPERATURE - Abstract
In this study, we evaluated the thermal environments of different tennis courts using wet-bulb globe temperature (WBGT) meters. WBGT meters were installed in an outdoor hard court, sand-filled artificial grass court, and clay court (a softball field), and measurements were taken hourly from 9:00 to 17:00 on weekdays from June 1 to September 21, 2022. The results were compared with data from different courts and the nearest Japan Meteorological Agency station (JMA WBGT) based on the Japan Sports Association's guidelines for exercise to prevent heat stroke. The median WBGT on each court was significantly higher for hard courts at the "Warning" (25 ≤ JMA WBGT < 28) level or above, sand-filled artificial grass courts at the "Severe Warning" (28 ≤ JMA WBGT < 31) level or above, and clay courts at the "Danger" (31 ≤ JMA WBGT) level than the JMA WBGT. Compared with the JMA WBGT, hard and sand-filled artificial grass courts are played on under particularly hot conditions. The results of this study could indicate to tournament organizers and coaches the importance of measuring the WBGT on each court surface from an early stage to prevent heat-related incidents. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Association between wet-bulb globe temperature and kidney function in different geographic regions in a large Taiwanese population study.
- Author
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Su, Wei-Yu, Wu, Ping-Hsun, Lin, Ming-Yen, Wu, Pei-Yu, Tsai, Yi-Chun, Chiu, Yi-Wen, Chang, Jer-Ming, Hung, Chih-Hsing, Wu, Chih-Da, Kuo, Chao-Hung, and Chen, Szu-Chia
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MACHINE learning , *TAIWANESE people , *GLOMERULAR filtration rate , *CHRONIC kidney failure , *KIDNEY physiology - Abstract
The worldwide prevalence and incidence rates of end-stage renal disease have been increasing, and the trend is pronounced in Taiwan. This is especially evident in southern Taiwan, where the wet-bulb globe temperature (WBGT) is consistently higher than in other regions. The association between kidney function and WBGT has not been fully investigated. Therefore, the aim of this study was to evaluate the association between estimated glomerular filtration rate (eGFR) and WBGT and variations in this association across different geographic regions in Taiwan. We used the Taiwan Biobank (TWB) to obtain data on community-dwelling individuals, linked these data with WBGT data obtained from the Central Weather Bureau and then processed the data using a machine learning model. WBGT data were recorded during the working period of the day from 8:00 a.m. to 5:00 p.m. These data were then compiled as 1-year, 3-year and 5-year averages, recorded prior to the survey year of the TWB of each participant. We identified 114 483 participants who had WBGT data during 2012–2020. Multivariable analysis showed that, in northern Taiwan, increases in 1- and 3-year averages of WBGT during the working period (β = −0.092, P = .043 and β = −0.193, P < .001, respectively) were significantly associated with low eGFR. In southern Taiwan, increases in 1-, 3- and 5-year averages of WBGT during the working period (β = −0.518, P < .001; β = −0.690, P < .001; and β = −0.386, P = .001, respectively) were gnificantly associated with low eGFR. These findings highlight the importance of heat protection for people working outdoors or in high-temperature environments as a measure to prevent negative impacts on kidney function. Moreover, we observed that in southern Taiwan, every 1°C increase in WBGT had a greater impact on the decrease in eGFR compared with other regions in Taiwan. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Analyzing Heat-Related Injuries at Fort Moore
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Beger, Anthony, Specking, Eric, Parnell, Gregory S., Pohl, Edward, Buchanan, Randy K., Anderson, William, Gallarno, George, Richards, John, Salado, Alejandro, editor, Valerdi, Ricardo, editor, Steiner, Rick, editor, and Head, Larry, editor
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- 2024
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5. A Novel Conceptual Model for Human Heat Tolerance.
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Bernard, Thomas E., Wolf, S. Tony, and Kenney, W. Larry
- Abstract
We propose a novel quantification of absolute human heat tolerance based on empirical assessment of the environment and individual modifiers. Human "heat tolerance" has no accepted definition or physiological underpinnings; rather, it is almost always discussed in relative or comparative terms. We propose to use environmental limits to heat balance accounting for metabolic rate and clothing, that is, the environments for which heat stress becomes uncompensable for a specified metabolic rate and clothing, as a novel metric for quantifying heat tolerance. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Amplification of the discrepancy between simplified and physics-based wet-bulb globe temperatures in a warmer climate
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Liying Qiu, Ziwei Zhu, Zixuan Zhou, Eun-Soon Im, Seung-Ki Min, Yeon-Hee Kim, Yujin Kim, Dong-Hyun Cha, Joong-Bae Ahn, and Young-Hwa Byun
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Heat stress ,Wet-bulb globe temperature ,Climate change ,Meteorology. Climatology ,QC851-999 - Abstract
The Simplified Wet Bulb Globe Temperature (sWBGT) is widely used in heat stress assessments for climate-change studies, but its limitations have not been thoroughly explored. Building on recent critiques of sWBGT's use for current climate on global scale, this study examines sWBGT's biases using dynamically-downscaled sub-daily climate projections under multiple future emission scenarios. The analysis is aimed at understanding caveats in the application of sWBGT and the uncertainties in existing climate change analysis dependent on sWBGT. Results indicate sWBGT's biases are heavily influenced by local near-surface air temperature, with overestimation of heat stress in East Asia regions, particularly hot and humid areas, due to static assumptions of radiation and wind speed. This overestimation is amplified in warmer climates, leading to exaggerated projected heat stress increases in future. In contrast, underestimations are found for heat stress levels attributed to low wind speeds and strong radiations, such as over the Tibetan Plateau and certain extreme events. Additionally, sWBGT underestimates variability in extreme heatwave events compared to WBGT in both current and future climates, irrespective of overestimation in absolute heatwave intensities. This study emphasizes the limitations of sWBGT, especially in future warmer climates. Importance of sub-daily data for capturing daily maximum heat stress level and reflecting diurnal variations in different components is also discussed. In conclusion, we recommend using Liljegren's model (i.e., physics-based calculation) with high-resolution sub-daily climate data for more accurate outdoor heat stress assessments in climate change studies.
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- 2024
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7. Predicting the body core temperature of recreational athletes at the end of a 10 km self‐paced run under environmental heat stress.
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Andrade, Marcelo T., Nunes‐Leite, Matheus M. S., Bruzzi, Rúbio S., Souza, Carlos H., Uendeles‐Pinto, João P., Prado, Luciano S., Soares, Danusa D., Gonçalves, Dawit A. P., Coimbra, Cândido C., and Wanner, Samuel P.
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BODY temperature , *AEROBIC capacity , *RUNNING speed , *ENDURANCE athletes , *TEMPERATURE control , *HEART beat - Abstract
New Findings: What is the central question of this study?The aim was to identify the factors predicting the body core temperature of athletes at the end of a 10 km self‐paced run in a hot environment.What is the main finding and its importance?Hyperthermia in athletes subjected to self‐paced running depends on several factors, highlighting the integrated control of core temperature during exercise under environmental heat stress. Five of the seven variables that significantly predicted core temperature are not invasive and, therefore, practical for use outside the laboratory environment: heart rate, sweat rate, wet‐bulb globe temperature, running speed and maximal oxygen consumption. Measurement of body core temperature (Tcore) is paramount to determining the thermoregulatory strain of athletes. However, standard measurement procedures of Tcore are not practical for extended use outside the laboratory environment. Therefore, determining the factors that predict Tcore during a self‐paced run is crucial for creating more effective strategies to minimize the heat‐induced impairment of endurance performance and reduce the occurrence of exertional heatstroke. The aim of this study was to identify the factors predicting Tcore values attained at the end of a 10 km time trial (end‐Tcore) under environmental heat stress. Initially, we extracted data obtained from 75 recordings of recreationally trained men and women. Next, we ran hierarchical multiple linear regression analyses to understand the predictive power of the following variables: wet‐bulb globe temperature, average running speed, initial Tcore, body mass, differences between Tcore and skin temperature (Tskin), sweat rate, maximal oxygen uptake, heart rate and change in body mass. Our data indicated that Tcore increased continuously during exercise, attaining 39.6 ± 0.5°C (mean ± SD) after 53.9 ± 7.5 min of treadmill running. This end‐Tcore value was primarily predicted by heart rate, sweat rate, differences between Tcore and Tskin, wet‐bulb globe temperature, initial Tcore, running speed and maximal oxygen uptake, in this order of importance (β power values corresponded to 0.462, −0.395, 0.393, 0.327, 0.277, 0.244 and 0.228, respectively). In conclusion, several factors predict Tcore in athletes subjected to self‐paced running under environmental heat stress. Moreover, considering the conditions investigated, heart rate and sweat rate, two practical (non‐invasive) variables, have the highest predictive power. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Associations between short-term temperature exposure and kidney-related conditions in New York State: The influence of temperature metrics across four dimensions
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Lingzhi Chu, Kai Chen, Susan Crowley, and Robert Dubrow
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Kidney disease ,Temperature ,Heat exposure ,Climate change ,Spatial resolution ,Wet-bulb globe temperature ,Environmental sciences ,GE1-350 - Abstract
Background: Evidence describing the relationship between short-term temperature exposure and kidney-related conditions is insufficient. It remains unclear how temperature specification affects estimation of these associations. This study aimed to assess associations between short-term temperature exposure and seven kidney-related conditions and to evaluate the influence of temperature specification. Methods: We obtained data on hospital encounters in New York State (2007–2016). We assessed associations with a case-crossover design using conditional logistic regression with distributed lag non-linear models. We compared model performance (i.e., AIC) and association curves using 1) five temperature spatial resolutions; 2) temperature on an absolute versus relative scale; 3) seven temperature metrics incorporating humidity, wind speed, and/or solar radiation; and 4) five intraday temperature measures (e.g., daily minimum and daytime mean). Results: We included 1,209,934 unplanned adult encounters. Temperature metric and intraday measure had considerably greater influence than spatial resolution and temperature scale. For outcomes not associated with temperature exposure, almost all metrics or intraday measures showed good model performance; for outcomes associated with temperature, there were meaningful differences in performance across metrics or intraday measures. For parsimony, we modelled daytime mean outdoor wet-bulb globe temperature, which showed good performance for all outcomes. At lag 0–6 days, we observed increased risk at the 95th percentile of temperature versus the minimum morbidity temperature for acute kidney failure (odds ratio [OR] = 1.36, 95% confidence interval [CI]: 1.09, 1.69), urolithiasis (OR = 1.41, 95% CI: 1.16, 1.70), dysnatremia (OR = 1.26, 95% CI: 1.01, 1.59), and volume depletion (OR = 1.88, 95% CI: 1.41, 2.51), but not for glomerular diseases, renal tubulo-interstitial diseases, and chronic kidney disease. Conclusions: High-temperature exposure over one week is a risk factor for acute kidney failure, urolithiasis, dysnatremia, and volume depletion. The differential model performance across temperature metrics and intraday measures indicates the importance of careful selection of exposure metrics when estimating temperature-related health burden.
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- 2023
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9. Effects of Road Components and Roadside Vegetation on Temperature Reduction in Seoul Considering Air, Wet-Bulb Globe, and Surface Temperatures.
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Cho, Hyejin
- Abstract
Urbanization has resulted in high temperatures in cities, which are exacerbated by an increase in urban impervious surfaces (road space). This study investigated the effect of urban road characteristics on roadside temperature. Different temperature indices were measured at four sites in Seoul with different road designs by using weather measuring devices and infrared thermal cameras. The differences between air and roadside air temperatures decreased from site 1 (no vegetation) to site 4 (roadside trees and vegetated medians). The analysis results showed that roadside wet-bulb globe and surface thermal temperatures sensitively changed according to road characteristics, unlike air temperature. The lowest temperatures were consistently observed at site 4. This cooling tendency was the strongest in the afternoon, which indicates the effectiveness of vegetation for preventing the commonly observed temperature rise in the afternoon. That is, roadside trees and vegetation in the median strip can prevent temperature rise and contribute to urban temperature reduction. Therefore, more roadside trees and median planting, as well as taller trees and denser vegetation along roads, can be used to provide a greater reduction of roadside temperatures and to improve urban climates. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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10. Applicability of WBGT index in determining the allowable working time in hot climate conditions
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Davood Afshari, Maryam Nourollahi-Darabad, and Gholam-Abbas Shirali
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reserve heart rate ,heat stress ,wet-bulb globe temperature ,Environmental pollution ,TD172-193.5 - Abstract
Introduction: Heat stress is a critical problem in hot industries, especially in incredibly hot climates. It can greatly impair the work process and put the health of workers at risk. This study aims to investigate the applicability of the WBGT index in determining the allowable working time in very hot weather conditions in one of the steel industries in Ahvaz. Material and Methods: This study was conducted in different sectors of a steel industry in Ahwaz. The physiological parameters of sixty workers working in different parts of the industry were evaluated. Environmental variables and the Wet-Bulb globe temperature (WBGT) Index were also simultaneously measured during work shifts. The acceptable work time was calculated based on the reserve heart rate (RHR) and the WBGT index. Results: The heat stress index among all occupational groups, based on the WBGT index, was incredibly high and surpassed the recommended level (P
- Published
- 2021
11. NOTES AND CORRESPONDENCE UV Parasol, Dry-Mist Spraying, and Street Trees as Tools for Heat Stress Mitigation.
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Hiroyuki KUSAKA, Yusuke NAKAMURA, and Yuki ASANO
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URBAN trees , *HOT weather conditions , *HEAT stroke , *SUNSHINE - Abstract
Ultraviolet (UV) parasols are a reasonable countermeasure against heat stress as they are portable and inexpensive. This study compared the heat stress mitigation effect of a UV parasol with that of street trees and drymist spraying on a hot and humid summer day in Japan. We observed meteorological elements and calculated the universal thermal climate index (UTCI) and wet-bulb globe temperature (WBGT) under UV parasol, street trees, dry-mist spraying, and direct sunlight. The observed UTCI and WBGT under the UV parasol were lower than those in direct sunlight by 4.4°C and 1.3°C, respectively, because of the decrease in black-globe temperature caused by the reduced downward shortwave radiation. This demonstrated that UV parasol reduced heatstroke risk by one level. The effect of the UV parasol was = 75 % of that of the street trees from the perspective of UTCI. The street trees reduced the UTCI and WBGT by 5.9°C and 1.9°C, respectively, compared with those in direct sunlight, resulting in the reduction of heatstroke risk by one level. In contrast, dry-mist spraying did not mitigate heat stress in conditions with moderate winds. Although the results of this study were obtained from observations on a single day, comparison with earlier studies confirms that the values observed in this study are representative results on summer days in Japan. [ABSTRACT FROM AUTHOR]
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- 2022
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12. A New, Zero-Iteration Analytic Implementation of Wet-Bulb Globe Temperature: Development, Validation, and Comparison With Other Methods.
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Kong Q and Huber M
- Abstract
Wet-bulb globe temperature (WBGT)-a standard measure for workplace heat stress regulation-incorporates the complex, nonlinear interaction among temperature, humidity, wind and radiation. This complexity requires WBGT to be calculated iteratively following the recommended approach developed by Liljegren and colleagues. The need for iteration has limited the wide application of Liljegren's approach, and stimulated various simplified WBGT approximations that do not require iteration but are potentially seriously biased. By carefully examining the self-nonlinearities in Liljegren's model, we develop a zero-iteration analytic approximation of WBGT while maintaining sufficient accuracy and the physical basis of the original model. The new approximation slightly deviates from Liljegren's full model-by less than 1°C in 99% cases over 93% of global land area. The annual mean and 75%-99% percentiles of WBGT are also well represented with biases within ± 0.5 °C globally. This approximation is clearly more accurate than other commonly used WBGT approximations. Physical intuition can be developed on the processes controlling WBGT variations from an energy balance perspective. This may provide a basis for applying WBGT to understanding the physical control of heat stress., Competing Interests: The authors declare no conflicts of interest relevant to this study., (© 2024 The Author(s). GeoHealth published by Wiley Periodicals LLC on behalf of American Geophysical Union.)
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- 2024
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13. Heat exposure limits for young unacclimatized males and females at low and high humidity.
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Wolf, S. Tony, Bernard, Thomas E., and Kenney, W. Larry
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HEAT , *EXERCISE tests , *BODY temperature , *HUMIDITY , *PHYSIOLOGICAL effects of heat , *MEN , *WOMEN , *SEX distribution , *BODY temperature regulation , *ENVIRONMENTAL exposure , *ACCLIMATIZATION - Abstract
Little is known about the separate and combined influences of humidity conditions, sex, and aerobic fitness on heat tolerance in unacclimatized males and females. The purpose of the current study was to describe heat tolerance, in terms of critical WBGT (WBGTcrit), in unacclimatized young males and females in hot-dry (HD) and warm-humid (WH) environments. Eighteen subjects (9 M/9F; 21 ± 2 yr) were tested during exercise at 30% V̇O2max in a controlled environmental chamber. Progressive heat stress exposures were performed with either (1) constant dry-bulb temperature (Tdb) of 34 and 36 °C and increasing ambient water vapor pressure (Pa) (Pcrit trials; WH); or (2) constant Pa of 12 and 16 mmHg and increasing Tdb (Tcrit trials; HD). Chamber Tdb and Pa, and subject esophageal temperature (Tes), were continuously monitored throughout each trial. After a 30-min equilibration period, progressive heat stress continued until subject heat balance could no longer be maintained and a clear rise in Tes was observed. Absolute WBGTcrit and WBGTcrit adjusted to a metabolic rate of 300 W (WBGT300), and the difference between WBGTcrit and occupational exposure limits (OEL; ΔOEL) was assessed. WBGTcrit, WBGT300, and ΔOEL were higher in WH compared to HD (p < 0.0001) for females but were the same between environments for males (p ≥ 0.21). WBGTcrit was higher in females compared to males in WH (p < 0.0001) but was similar between sexes in HD (p = 0.44). When controlling for metabolic rate, WBGT300 and ΔOEL were higher in males compared to females in WH and HD (both p < 0.0001). When controlling for sex, V̇O2max was not associated with WBGT300 or ΔOEL for either sex (r ≤ 0.12, p ≥ 0.49). These findings suggest that WBGTcrit is higher in females compared to males in WH, but not HD, conditions. Additionally, the WBGTcrit is lower in females, but not males, in HD compared to WH conditions. [ABSTRACT FROM AUTHOR]
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- 2022
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14. Assessing the impact of summer heat on the movement of people in Tokyo based on mobile phone location data.
- Author
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Kumakura, Eiko, Ashie, Yasunobu, and Ueno, Takahiro
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Using human location data from mobile phones, we developed a method to detail transportation modes around Shinagawa Station in Tokyo and analyzed the impact of hot weather conditions on traffic behavior. Each user's movement history was collected based on the global positioning system (GPS) communication of applications. We estimated the modes of transportation (train, car, walking, and stationary) for each user. By conducting route searches based on each user's data, we calculated the traffic volume for each mode of transportation, linking the estimated population data to network data and confirming accuracy against official census data. In August 2019, we examined the relationship between the estimated transportation modes and the hourly wet-bulb globe temperature (WBGT), which was calculated by the Ministry of the Environment using values measured by the Tokyo Regional Meteorological Observatory. The results indicated that as WBGT increases, fewer pedestrians walk and more remain stationary. Sensitivity to WBGT was four times greater at 20:00 p.m. than at 08:00 a.m., despite similar WBGT levels. This may be because fewer people go out during the hottest part of the day, and the sum of those who go out during the day, i.e., those who return home, is greatly reduced. However, this trend was not observed on weekdays. The results suggest that the impact of summer heat is latent during weekdays due to the demands of work and errands but becomes more pronounced during free time, such as holidays and nighttime. • Proposed methodology can extract highly detailed modes of human transportation. • Pedestrian responses to weather based on land use and time of day were estimated. • High WBGT leads to decreased walking activity, especially on holidays. • Reduction in pedestrian numbers due to WBGT rise is greater at night than in morning. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Explicit Calculations of Wet‐Bulb Globe Temperature Compared With Approximations and Why It Matters for Labor Productivity.
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Kong, Qinqin and Huber, Matthew
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LABOR productivity ,STRAINS & stresses (Mechanics) ,ENVIRONMENTAL indicators ,CLIMATE change ,INDUSTRIAL hygiene ,FLOOD warning systems - Abstract
Wet‐bulb globe temperature (WBGT) is a widely applied heat stress index. However, most applications of WBGT within the heat stress impact literature that do not use WBGT at all, but use one of the ad hoc approximations, typically the simplified WBGT (sWBGT) or the environmental stress index (ESI). Surprisingly, little is known about how well these approximations work for the global climate and climate change settings that they are being applied to. Here, we assess the bias distribution as a function of temperature, humidity, wind speed, and radiative conditions of both sWBGT and ESI relative to a well‐validated, explicit physical model for WBGT developed by Liljegren, within an idealized context and the more realistic setting of ERA5 reanalysis data. sWBGT greatly overestimates heat stress in hot‐humid areas. ESI has much smaller biases in the range of standard climatological conditions. Over subtropical dry regions, both metrics can substantially underestimate extreme heat. We show systematic overestimation of labor loss by sWBGT over much of the world today. We recommend discontinuing the use of sWBGT. ESI may be acceptable for assessing average heat stress or integrated impact over a long period like a year, but less suitable for health applications, extreme heat stress analysis, or as an operational index for heat warning, heatwave forecasting, or guiding activity modification at the workplace. Nevertheless, Liljegren's approach should be preferred over these ad hoc approximations and we provide a fast Python implementation to encourage its widespread use. Plain Language Summary: Wet‐bulb globe temperature (WBGT) is a widely applied heat stress index. However, most applications of WBGT within the climate change heat stress impact literature that do not use WBGT at all but use one of the ad hoc approximations, typically the simplified WBGT (sWBGT) or sometimes the environmental stress index (ESI). But we know little about how well these approximations work for measuring heat stress. Here, we evaluate the performance of sWBGT and ESI against a well‐validated, explicit physical model of WBGT. sWBGT greatly overestimates heat stress under a hot, humid climate. ESI performs much better in measuring average heat stress. But they both may seriously underestimate severe heat stress, especially in hot, dry regions. Our results suggest that previous studies using sWBGT tend to dramatically overestimate heat stress and its economic and health implications, which may further misinform policymaking. We recommend discontinuing the use of sWBGT. ESI may be acceptable for assessing average heat stress, but less suitable for the warning or forecasting of extreme heat, or providing guidance for dealing with workplace heat stress. Nevertheless, the well‐validated physical model of WBGT should be preferred over these approximations and we provide a Python implementation to encourage its widespread use. Key Points: We evaluate biases of two common approximations to Wet‐bulb globe temperature (WBGT) in comparison with explicitly calculated WBGT and consider labor implicationsSimplified WBGT generally overestimates heat stress and resulting labor loss, whereas environmental stress index is less biased. Both methods underestimate peak heat stressBoth methods are systematically biased. We offer a computationally efficient Python implementation to encourage accurate WBGT calculations [ABSTRACT FROM AUTHOR]
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- 2022
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16. Explicit Calculations of Wet‐Bulb Globe Temperature Compared With Approximations and Why It Matters for Labor Productivity
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Qinqin Kong and Matthew Huber
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heat stress ,wet‐bulb globe temperature ,simplified wet‐bulb globe temperature ,environmental stress index ,bias assessment ,labor productivity ,Environmental sciences ,GE1-350 ,Ecology ,QH540-549.5 - Abstract
Abstract Wet‐bulb globe temperature (WBGT) is a widely applied heat stress index. However, most applications of WBGT within the heat stress impact literature that do not use WBGT at all, but use one of the ad hoc approximations, typically the simplified WBGT (sWBGT) or the environmental stress index (ESI). Surprisingly, little is known about how well these approximations work for the global climate and climate change settings that they are being applied to. Here, we assess the bias distribution as a function of temperature, humidity, wind speed, and radiative conditions of both sWBGT and ESI relative to a well‐validated, explicit physical model for WBGT developed by Liljegren, within an idealized context and the more realistic setting of ERA5 reanalysis data. sWBGT greatly overestimates heat stress in hot‐humid areas. ESI has much smaller biases in the range of standard climatological conditions. Over subtropical dry regions, both metrics can substantially underestimate extreme heat. We show systematic overestimation of labor loss by sWBGT over much of the world today. We recommend discontinuing the use of sWBGT. ESI may be acceptable for assessing average heat stress or integrated impact over a long period like a year, but less suitable for health applications, extreme heat stress analysis, or as an operational index for heat warning, heatwave forecasting, or guiding activity modification at the workplace. Nevertheless, Liljegren's approach should be preferred over these ad hoc approximations and we provide a fast Python implementation to encourage its widespread use.
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- 2022
- Full Text
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17. Wisteria trellises and tents as tools for improved thermal comfort and heat stress mitigation: Meteorological, physiological, and psychological analyses considering the relaxation effect of greenery.
- Author
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Kusaka, Hiroyuki, Asano, Yuki, and Kimura, Ryuhei
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THERMAL comfort , *TENTS , *LEAF temperature , *SOLAR radiation , *SURFACE temperature , *URBAN heat islands - Abstract
In this study, wet‐bulb globe temperature (WBGT) was measured under wisteria trellises, under tents, and in direct sunlight. In addition, a subject experiment was conducted to consider the relaxation effect of the greenery. In terms of WBGT, the risk of heatstroke under the wisteria trellis was one level lower than that in direct sunlight. The mitigation effect of the wisteria trellis was greater than that of the tent. The difference in WBGT beneath the wisteria trellis and under the tent was primarily due to varied black‐globe temperature (i.e., the difference in radiation environment). The wisteria trellis blocked most of the solar radiation, and its effect on the small aggregation of leaves reduced the increase in the leaf surface temperature and downward longwave radiation. The tent material allowed more solar radiation and increased the temperature of the tent surface. The questionnaire responses revealed that the subjects felt cooler and more comfortable under the wisteria trellis than under the tent, with or without a blindfold. [ABSTRACT FROM AUTHOR]
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- 2022
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18. An investigation into environmental variables influencing post‐race exertional heat illness in thoroughbred racehorses in temperate eastern Australia.
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Brownlow, MA and Brotherhood, JR
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RACE horses , *THOROUGHBRED horse , *VAPOR pressure , *WIND speed , *HORSE shows , *CENTRAL nervous system , *BODY temperature - Abstract
Exertional heat illness (EHI) is a syndrome that occurs when metabolic heat production from muscular contraction exceeds the rate at which it can be dissipated. Core body temperature rises to critical levels, causing hyperthermia and central nervous system dysfunction. Best practice for the prevention of EHI centres around early detection, rapid response and aggressive cooling. Advance planning enables risk mitigation measures. The more that is known about EHI in horses, the better prepared those in the positions of responsibility can be to anticipate events in which the risk of EHI may be elevated. This prospective, observational study investigated environmental risk factors associated with the occurrence of EHI. From 2014 to 2018, the number of horses exhibiting the symptoms of post‐race EHI was recorded at 73 convenience sampled race meetings. Of the 4809 starters, the signs of EHI were recorded for 457. Thermal environmental data were measured and included ambient temperature, radiant heat, vapor pressure (humidity) and wind speed (WS). Mixed linear regression models were computed to assess the associations between the occurrence and incidence of post‐race EHI and the four thermal environmental variables. The analysis showed that vapor pressure and WS had the largest effects on the occurrence of post‐race EHI. The major limitations were that the race meetings selected were convenience sampled according to attendance by the first author and individual horse data were not available. EHI is influenced by a complex interaction of independently acting environmental variables, but warm, windless, humid days are most likely to result in the cases of EHI. [ABSTRACT FROM AUTHOR]
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- 2021
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19. Wisteria trellises and tents as tools for improved thermal comfort and heat stress mitigation: Meteorological, physiological, and psychological analyses considering the relaxation effect of greenery
- Author
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Hiroyuki Kusaka, Yuki Asano, and Ryuhei Kimura
- Subjects
heat stress mitigation ,thermal comfort improvement ,urban heat island mitigation ,urban trees ,wet‐bulb globe temperature ,wisteria trellises ,Meteorology. Climatology ,QC851-999 - Abstract
Abstract In this study, wet‐bulb globe temperature (WBGT) was measured under wisteria trellises, under tents, and in direct sunlight. In addition, a subject experiment was conducted to consider the relaxation effect of the greenery. In terms of WBGT, the risk of heatstroke under the wisteria trellis was one level lower than that in direct sunlight. The mitigation effect of the wisteria trellis was greater than that of the tent. The difference in WBGT beneath the wisteria trellis and under the tent was primarily due to varied black‐globe temperature (i.e., the difference in radiation environment). The wisteria trellis blocked most of the solar radiation, and its effect on the small aggregation of leaves reduced the increase in the leaf surface temperature and downward longwave radiation. The tent material allowed more solar radiation and increased the temperature of the tent surface. The questionnaire responses revealed that the subjects felt cooler and more comfortable under the wisteria trellis than under the tent, with or without a blindfold.
- Published
- 2022
- Full Text
- View/download PDF
20. Factors Affecting Incidence Rate of Exertional Heat Illnesses: Analysis of 6 Years of High School Football Practices in North Central Florida.
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Tripp, Brady L., Winkelmann, Zachary K., Eberman, Lindsey E., and Smith, Michael Seth
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HIGH schools ,SYNCOPE ,HEAT exhaustion ,HEAT stroke ,TEMPERATURE ,CONFIDENCE intervals ,PHYSIOLOGICAL effects of heat ,RESEARCH methodology ,DISEASE incidence ,REGRESSION analysis ,RISK assessment ,DESCRIPTIVE statistics ,FOOTBALL ,DATA analysis software ,EPIDEMIOLOGICAL research ,ENVIRONMENTAL exposure - Abstract
Background: Although experts have advocated for regionally specific heat safety guidelines for decades, guidelines have not been universally adopted. Purpose: To describe the rate and risk factors associated with exertional heat illness (EHI). Study Design: Descriptive epidemiology study. Methods: For a 3-month period (August-October) over 6 years (2013-2018), athletic trainers at 13 high schools in North Central Florida recorded varsity football practice time and length, wet-bulb globe temperature (WBGT), and incidences of EHI, including heat stroke, heat exhaustion, and heat syncope. Results: Athletes sustained 54 total EHIs during 163,254 athlete-exposures (AEs) for the 3-month data collection periods over 6 years (incidence rate [IR], 3.31 /10,000 AEs). Heat exhaustion accounted for 59.3% (32/54), heat syncope 38.9% (21/54), and heat stroke 1.9% (1/54) of all EHIs recorded. Of the EHIs, 94.4% (51/54) were experienced within the first 19 practices. The first 19 practices had an IR of 7.48 of 10,000 AEs, and the remaining 44 practices had an IR of 0.32 of 10,000 AEs, demonstrating that the risk of EHI for practices 1 to 19 was 23.7 times that of the remaining practices. When comparing morning to afternoon practices, 35.2% (19/54) EHI incidents occurred during morning practices. The risk of EHI during practices with WBGT >82°F (27.8°C) was 3.5 times that of practices with WBGT <82°F. Conclusion: In the current study, the risk of EHI was greatest in the first 19 practices of the season and during practices with WBGT >82°F. As modifiable risk factors for EHI, increased vigilance and empowerment to adhere to acclimatization guidelines can mitigate EHI risk. Health care providers must continue to advocate for implementation of regulations and the authority to make decisions to ensure patient safety. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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21. 高齢者の熱中症が室内で発症し得る室温のIoT を用いた観察研究.
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山下 駿, 多胡雅毅, 織田良正, 織田正道, and 山下秀一
- Abstract
Copyright of Japanese Journal of Biometeorology is the property of Japanese Society of Biometeorology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
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22. Evaluation of the physiological changes in prehospital health‐care providers influenced by environmental factors in the summer of 2020 during the COVID‐19 pandemic
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Shota Tanaka, Koshi Nakagawa, Yuki Ozone, Yuuki Kaneko, Shota Sugiki, Genki Hoshino, Shunsuke Saito, Arisa Minami, and Hideharu Tanaka
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Humid ,personal protective equipment ,summer ,temperature ,wet‐bulb globe temperature ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Aim Wearing personal protective equipment (PPE) is essential to prevent infection transmission, but the risk of heatstroke increases with wearing PPE in a humid and hot environment. Therefore, we aimed to examine how environmental parameters change the body physiology in a hot environment during the coronavirus disease (COVID‐19) pandemic. Methods This was a retrospective cohort study extracted from the MEDIC Japan heatstroke prevention database, which was recorded between 1 August and 7 September, 2020. Its database is a registry collection from seven healthy health‐care providers. Subjects recorded their own vital signs (forehead and tympanic temperature, blood pressure, pulse rate, and oxygen saturation) and environmental factors (type of weather, wet‐bulb globe temperature [WBGT], air temperature, humidity, and location) every hour during their working shift. Results From 323 records, a weak positive but statistically significant correlation was observed between WBGT and pulse rate (correlation coefficient [95% confidence interval], r = 0.34 [0.23, 0.45]) and between WBGT and core body temperature. Forehead temperature had a stronger correlation than tympanic temperature (forehead, r = 0.33 [0.21, 0.43]; tympanic, r = 0.17 [0.05, 0.28]), which also showed a larger effect (forehead, η2 = 0.08; tympanic, η2 = 0.05). The effect size of oxygen saturation measured outdoors was large (η2 = 0.30). Forehead temperature increased abruptly at 28°C WBGT and at 33°C air temperature. Conclusion A hot environment significantly affected forehead temperature, and the daytime imposed a high risk of heatstroke. To avoid heatstroke, environmental parameters are important to note as outdoor environments had a large effect on vital sign changes depending on the time of day.
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- 2021
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23. Diverse Effects of Thermal Conditions on Performance of Marathon Runners
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Thadeu Gasparetto and Cornel Nesseler
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performance ,marathon ,heat stress ,wet-bulb globe temperature ,universal thermal climate index ,Psychology ,BF1-990 - Abstract
Heat exposure affects human performance in many ways. Both physiological (i.e., glycogen sparing, oxygen uptake, thermoregulation) and biomechanical mechanisms (i.e., contact time, knee flexion, muscle activity) are affected, hence reducing performance. However, the exposure affects persons differently. Not all athletes necessarily experience an identical thermal condition similarly, and this point has been overlooked to date. We analyzed endurance performances of the top 1000 runners for every year during the last 12 New York City Marathons. Thermal conditions were estimated with wet-bulb globe temperature (WBGT) and universal thermal climate index (UTCI). Under identical thermal exposure, the fastest runners experienced a larger decline in performance than the slower ones. The empirical evidence offered here not only shows that thermal conditions affect runners differently, but also that some groups might consistently suffer more than others. Further research may inspect other factors that could be affected by thermal conditions, as pacing and race strategy.
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- 2020
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24. Statistical post‐processing of heat index ensemble forecasts: Is there a royal road?
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Baran, Sándor, Baran, Ágnes, Pappenberger, Florian, and Ben Bouallègue, Zied
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- *
DEW point , *FORECASTING , *EXTREME value theory , *LEAD time (Supply chain management) , *MACHINE learning - Abstract
We investigate the effect of statistical post‐processing on the probabilistic skill of discomfort index (DI) and indoor wet‐bulb globe temperature (WBGTid) ensemble forecasts, both calculated from the corresponding forecasts of temperature and dew point temperature. Two different methodological approaches to calibration are compared. In the first case, we start with joint post‐processing of the temperature and dew point forecasts and then create calibrated samples of DI and WBGTid using samples from the obtained bivariate predictive distributions. This approach is compared with direct post‐processing of the heat index ensemble forecasts. For this purpose, a novel ensemble model output statistics model based on a generalized extreme value distribution is proposed. The predictive performance of both methods is tested on the operational temperature and dew point ensemble forecasts of the European Centre for Medium‐Range Weather Forecasts and the corresponding forecasts of DI and WBGTid. For short lead times (up to day 6), both approaches significantly improve the forecast skill. Among the competing post‐processing methods, direct calibration of heat indices exhibits the best predictive performance, very closely followed by the more general approach based on joint calibration of temperature and dew point temperature. Additionally, a machine learning approach is tested and shows comparable performance for the case when one is interested only in forecasting heat index warning level categories. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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25. Diverse Effects of Thermal Conditions on Performance of Marathon Runners.
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Gasparetto, Thadeu and Nesseler, Cornel
- Abstract
Heat exposure affects human performance in many ways. Both physiological (i.e., glycogen sparing, oxygen uptake, thermoregulation) and biomechanical mechanisms (i.e., contact time, knee flexion, muscle activity) are affected, hence reducing performance. However, the exposure affects persons differently. Not all athletes necessarily experience an identical thermal condition similarly, and this point has been overlooked to date. We analyzed endurance performances of the top 1000 runners for every year during the last 12 New York City Marathons. Thermal conditions were estimated with wet-bulb globe temperature (WBGT) and universal thermal climate index (UTCI). Under identical thermal exposure, the fastest runners experienced a larger decline in performance than the slower ones. The empirical evidence offered here not only shows that thermal conditions affect runners differently, but also that some groups might consistently suffer more than others. Further research may inspect other factors that could be affected by thermal conditions, as pacing and race strategy. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
26. Heat Policy Revision for Georgia High School Football Practices Based on Data-Driven Research.
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Cooper, Earl R., Grundstein, Andrew J., Miles, Jessica D., Ferrara, Michael S., Curry, Patrick, Casa, Douglas J., and Yuri Hosokawa
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- *
CLINICAL medicine , *CONFIDENCE intervals , *ENVIRONMENTAL health , *EPIDEMIOLOGICAL research , *FOOTBALL , *HEAT , *HEAT stroke , *HIGH schools , *RESEARCH methodology , *EVALUATION of medical care , *HEALTH policy , *RESEARCH funding , *SYNCOPE , *HEAT exhaustion , *DESCRIPTIVE statistics - Abstract
Context: Interscholastic heat policies for football have not been evidence based. Therefore, their effectiveness in mitigating exertional heat illness has not been assessed. Objective: To discuss the development of the Georgia High School Association heat policy and assess the effectiveness of revised guidelines. Design: Descriptive epidemiology study. Setting: Georgia high schools. Patients or other participants: Interscholastic football players in grades 9 through 12. Main outcome measure(s): Heat syncope and heat exhaustion (HS/HE) illness rates (IRs) were calculated per 1000 athlete-exposures (AEs), and relative risk (RR) was calculated as a ratio of postpolicy (POST) IR divided by prepolicy (PRE) IR. Results: A total of 214 HS/HE cases (172 PRE, 42 POST) and 341 348 AEs (178 230 PRE, 163 118 POST) were identified. During the first 5 days of the PRE period, approximately 50% of HS/HE illnesses occurred; HS/HE IRs doubled when practice sessions increased from 2 to 2.5 hours and tripled for practices ≥3 hours. The HS/HE IRs in the PRE period increased from 0.44/1000 AEs for wet-bulb globe temperatures (WBGTs) of <82°F (<27.8°C) to >2.0/1000 AEs for WBGTs from 87°F (30.6°C) to 89.9°F (32.2°C). The RRs comparing PRE and POST policy periods were 0.29 for WBGTs of <82.0°F (<27.80°C), 0.65 for WBGTs from 82.0°F (27.8°C) to 86.9°F (30.5°C), and 0.23 for WBGTs from 87.0°F (30.6°C) to 89.9°F (32.2°C). No HS/HE illnesses occurred in the POST period for WBGTs at >90°F (>32.3°C). Conclusions: Results from the PRE period guided the Georgia High School Association to revise its heat and humidity policy to include a mandated 5-day acclimatization period when no practices may exceed 2 hours and the use of WBGT-based activity-modification categories. The new policy reduced HS/HE IRs by 35% to 100%, depending on the WBGT category. Our results may be generalizable to other states with hot and humid climates similar to that of Georgia. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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27. A Field Evaluation of Construction Workers' Activity, Hydration Status, and Heat Strain in the Extreme Summer Heat of Saudi Arabia.
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Al-Bouwarthan, Mohammed, Quinn, Margaret M, Kriebel, David, and Wegman, David H
- Subjects
- *
CLIMATOLOGY , *CONSTRUCTION industry , *HEART beat , *HEAT , *HYDRATION , *LONGITUDINAL method , *SEASONS , *TEMPERATURE , *EMPLOYEES' workload , *OCCUPATIONAL hazards , *ENVIRONMENTAL exposure , *BODY movement , *DATA analysis software , *DESCRIPTIVE statistics - Abstract
Objectives Assess the impact of summer heat exposure (June–September) on residential construction workers in Al-Ahsa, Saudi Arabia by evaluating (i) heart rate (HR) responses, hydration status, and physical workload among workers in indoor and outdoor construction settings, (ii) factors related to physiological responses to work in hot conditions, and (iii) how well wet-bulb globe temperature-based occupational exposure limits (WBGTOELs) predict measures of heat strain. Methods Twenty-three construction workers (plasterers, tilers, and laborers) contributed 260 person-days of monitoring. Workload energy expenditure, HR, fluid intake, and pre- and postshift urine specific gravity (USG) were measured. Indoor and outdoor heat exposures (WBGT) were measured continuously and a WBGTOEL was calculated. The effects of heat exposure and workload on heart rate reserve (HRR), a measure of cardiovascular strain, were examined with linear mixed models. A metric called 'heat stress exceedance' (HSE) was constructed to summarize whether the environmental heat exposure (WBGT) exceeded the heat stress exposure limit (WBGTOEL). The sensitivity and specificity of the HSE as a predictor of cardiovascular strain (HRR ≥30%) were determined. Results The WBGTOEL was exceeded frequently, on 63 person-days indoors (44%) and 91(78%) outdoors. High-risk HRR occurred on 26 and 36 person-days indoors and outdoors, respectively. The HSE metric showed higher sensitivity for HRR ≥30% outdoors (89%) than indoors (58%) and greater specificity indoors (59%) than outdoors (27%). Workload intensity was generally moderate, with light intensity work more common outdoors. The ability to self-pace work was associated with a lower frequency of HRR ≥30%. USG concentrations indicated that workers began and ended their shifts dehydrated (USG ≥1.020). Conclusions Construction work where WBGTOEL is commonly exceeded poses health risks. The ability of workers to self-pace may help reduce risks. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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28. Comparison of wet bulb globe temperature measured on-site vs estimated and the impact on activity modification in high school football.
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Tripp, Brady, Vincent, Heather K, Bruner, Michelle, and Smith, Michael Seth
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- *
HIGH school football , *FOOTBALL injuries , *BULBS (Plants) , *HIGH school football players , *ATHLETIC trainers , *COLLEGE sports , *SPORTS medicine - Abstract
Exertional heat stroke is one of the top three causes of death in young athletes, particularly high school football players. Despite evidence that these deaths are completely avoidable with appropriate prevention and treatment, deaths still occur at an alarming rate. Wet bulb globe temperature (WBGT) is the preferred method of both the National Athletic Trainers' Association and American College of Sports Medicine to measure heat intensity. Based on the WBGT, activity modification guidelines (AMG) dictate work-to-rest ratios, activity levels and duration, protective equipment worn, and length and frequency of hydration breaks. Due to the cost of handheld WBGT monitors, smartphone apps that estimate WBGT have been considered an alternative. However, it is unclear how WBGT values estimated by these smartphone apps compare to those measured on-site using handheld WBGT monitors. We compared WBGT values estimated by a commercial smartphone app to those taken on-site at the same time and place. Thirteen athletic trainers measured WBGT in the field during high school football practices over a three-month season in North Central Florida. A paired sample t-test indicated the smartphone app significantly overestimated WBGT (29.0°C ± 4.1°C) compared to on-site measures (26.4°C ± 3.2°C) (r =0.580; t(943)=-23.38, p <0.0001). The smartphone app-estimated values were consistently greater than on-site measures, resulting in potentially unnecessary activity modifications and cancellations if the app was used in place of on-site handheld WBGT monitors. Despite being significantly cheaper than handheld WBGT monitors, at this time, smartphone apps are not ready for widespread use to guide activity modification decisions. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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29. The association between wet-bulb globe temperature and other thermal indices (DI, MDI, PMV, PPD, PHS, PSI and PSIhr): a field study.
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Zare, Sajad, Hasheminejad, Naser, Bateni, Mokhles, Baneshi, Mohammad Reza, Shirvan, Hossein Elahi, and Hemmatjo, Rasoul
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FIELD research ,HEART beat ,TEMPERATURE ,INDUSTRIAL workers ,INDEX numbers (Economics) - Abstract
The current study aimed at comparing the correlation coefficients between wet-bulb globe temperature (WBGT) and a number of parameters, including the discomfort index (DI), modified discomfort index (MDI), predicted mean vote (PMV), predicted percentage of dissatisfaction (PPD), predicted heat strain (PHS), physiological strain index (PSI) and physiological strain index heart rate (PSI
hr ). In total, 30 workers of a pelletizing factory participated in this study. Environmental parameters and workers' physiological parameters were measured in 10 working stations. The results showed that effective WBGT (WBGTeff ) strongly correlates with DI, MDI, PMV, PPD, PHS, PSI and PSIhr . WBGTeff had the highest correlation coefficients with PMV, MDI, PHS and PSIhr . Based on the obtained results, it was concluded that heat stress exceeded the standard limit for a number of indices in some of the working stations. Thus, some controlling measures should be taken to reduce heat stress in these stations. [ABSTRACT FROM AUTHOR]- Published
- 2020
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30. The effect of heat stress on hematological parameters and oxidative stress among bakery workers.
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Gharibi, Vahid, Khanjani, Narges, Heidari, Hamidreza, Ebrahimi, Mohammad Hossein, and Hosseinabadi, Majid Bagheri
- Subjects
- *
PHYSIOLOGICAL effects of heat , *OXIDATIVE stress , *ERYTHROCYTES , *OXIDANT status , *LEUCOCYTES , *BLOOD cell count , *LYMPHOCYTE count , *CELL size - Abstract
Heat stress causes physiological changes, and changes in hematological parameters and hormonal levels in the human body, known as thermal strain. This study was conducted to determine the effect of exposure to heat stress on hematological parameters and oxidative stress in the bakers of Shahroud City, Iran. A total of 163 bakery workers (exposed group) and 135 office workers (unexposed group) with a minimum of 1-year working experience were selected. Exposure to heat stress was measured using ISO-7243 criteria on the hottest days of the year (late July and August). Wet-bulb globe temperature (WBGT) was calculated based on indoor environments. Oxidative stress indices including malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC) in the bakers' and office workers' serum and hematological parameters were measured. Statistical analysis was done through independent t -test, and multivariate linear regression using SPSS v24. Analysis of hematological parameters showed that about 70% and 68% of the bakers had abnormal mean cell volume (MCV) and white blood cell (WBC) count, respectively, while only around 12% of them had abnormal mean cell hemoglobin concentration (MCHC). The counts of red blood cells (RBC), WBC, lymphocytes (LYM), and MCV showed significant differences in different occupational groups (p < 0.05). The levels of MDA and NO were significantly higher in bakers with WBGT more than the threshold value (p < 0.05). The WBGT index for assessing heat stress can be used as a predictor variable for MDA and NO levels. In addition, heat stress exposure could be a risk factor for abnormal WBC, RBC, LYM, and MCV. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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31. Globe Temperature and Its Measurement: Requirements and Limitations.
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Oliveira, A Virgílio M, Raimundo, António M, Gaspar, Adélio R, and Quintela, Divo A
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- *
AIR , *PHYSIOLOGICAL effects of heat , *MEDICAL thermometers , *TEMPERATURE - Abstract
This study addresses the measurement of the globe temperature. For this purpose, two globe thermometers with different diameters (50 and 150 mm) and a variety of thermal environmental conditions were considered. The assessments of the response times and of the influences of the globe diameter and the air velocity on the measured globe temperatures are discussed. The results of the response times clearly put in evidence that the values usually stated in the literature can be questioned and that longer measurement periods must be considered. In fact, response times >30 min were obtained in 68% of the tests performed. Moreover, differences >20ºC were obtained between the 150 and 50 mm sensors, highlighting the influence of the globe diameter. The analysis of the effect of the air velocity on the globe temperature shows mean relative differences >30% between tests in still air and with the higher air velocity considered (1.81 m s–1). On the basis of measurements carried out with the 50 mm globe, correction equations to the standard globe temperature for both natural and forced convection are proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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32. Evaluation of indoor heat stress on workers of bakeries at Assiut City, Egypt.
- Author
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Rabeiy, R. E.
- Subjects
OCCUPATIONAL hazards ,HEAT exhaustion ,HEAT stroke ,PROTECTIVE clothing ,HEAT ,BAKERIES ,BODY temperature - Abstract
This study investigates indoor heat stress among employees engaged in bakeries in Assiut city. Heat stress is one of the occupational hazards especially in arid climates that impose negative impacts on workers such as heat rashes, heat exhaustion, heat cramps, heat fainting or heat stroke. In this research, 100 subjects were chosen randomly from 20 bakery stations to testify heat stress impacts. Heat stress levels were measured using wet-bulb globe temperature index (WBGT) to evaluate the impacts of environmental factors on the employees. The response of worker's body to this heat stress is expressed as physiological strain index (PSI) that can be estimated by measuring heart rate and core temperature. Results obtained from WBGT index measurements indicated that the average value of heat stress in bakeries reached 31.6 °C that is exceeding than threshold limit value (28 °C) and action limit (25 °C) recommended by American Conference of Government Industrial Hygienists. In addition, WBGT values were compared with the Egyptian Environmental Law 4/1994 and Egyptian Labor Low 12/2003. PSI values fall in the range of 200 < M (metabolic rate) < 260 indicating that workload in bakeries environment lies in the moderate class. According to the questionnaire data, several workers faced heat disorders including heat exhaustion (23 cases), heat cramps (17 cases), and heat stroke (5 cases). Application of control measures such as engineering control, administrative control, and personal protective equipment should be applied. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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33. New approach to identifying proper thresholds for a heat warning system using health risk increments.
- Author
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Cheng, Yu-Ting, Lung, Shih-Chun Candice, and Hwang, Jing-Shiang
- Subjects
- *
HEALTH risk assessment , *BIOLOGICAL adaptation , *CLIMATE change , *HEALTH outcome assessment , *HOSPITAL admission & discharge , *DEATH rate - Abstract
Abstract Background A critical adaptation strategy for reducing heat-related health risk under climate change is to establish a heat warning system with a proper threshold that requires evaluation of heat-health relationships using empirical data. Objectives This work presents a new approach to selecting proper health-based thresholds for a heat warning system which are different from thresholds of heat-health relationship. Methods The proposed approach examined heat-health relationships through analyzing 15 years of health records with a modified generalized additive model (GAM), compared risk ratio increments (RRIs) of threshold candidates against a reference, assessed frequency of days above these candidates, and presented results graphically for easy communication. The candidate with the maximum RRI and proper occurring frequency is potentially the best threshold. Three heat indicators, including wet-bulb globe temperature (WBGT), temperature (T), and apparent temperature (AT), as well as three health outcomes, including all-cause mortality, heat-related hospital admissions, and heat-related emergency visits were evaluated. Results Risk ratios for all three health outcomes showed a consistent rising trend with increasing threshold candidates for all three heat indicators among different age and gender groups. WBGT had the most obvious increasing trend of RRIs with the three health outcomes. The maximum RRI was observed in heat-related emergency visits (242%), followed by heat-related hospital admissions (73%), and all-cause mortality (9%). The RRIs assessed for the three health outcomes pointed to the same thresholds, 33.0 °C, 34.0 °C, and 37.5 °C for WBGT, T, and AT, respectively. The number of days above these thresholds and for warning to be issued ranged between 0 and 7 days during 2000–2014. Discussion This study demonstrated a new approach to determining heat-warning thresholds with different heat indicators and health outcomes. The proposed approach provides a straightforward, feasible, and flexible scientific tool that assists the authorities around the world in selecting a proper threshold for a heat warning system. Highlights • This work shows a new approach to select proper thresholds for heat warning systems. • Modified generalized additive model and risk ratio increments (RRIs) were applied. • Threshold of wet-bulb globe temperature (WBGT) at 33.0 °C were identified for Taiwan. • WBGT had the most obvious increasing trend of RRIs among three heat indicators. • The maximum RRI of WBGT was observed in emergency visits (242%). [ABSTRACT FROM AUTHOR]
- Published
- 2019
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34. The efficacy of weekly and bi-weekly heat training to maintain the physiological benefits of heat acclimation
- Author
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Yasuki Sekiguchi, Jeb F Struder, Robert A. Huggins, Rebecca L. Stearns, Lawrence E. Armstrong, Courteney L. Benjamin, Douglas J. Casa, Elaine C. Lee, Cody R. Butler, and Ciara N. Manning
- Subjects
Adult ,Male ,Hyperthermia ,Hot Temperature ,business.industry ,Acclimatization ,Wet-bulb globe temperature ,Repeated measures design ,Physical Therapy, Sports Therapy and Rehabilitation ,Middle Aged ,Thermoregulation ,medicine.disease ,Adaptation, Physiological ,Young Adult ,Animal science ,Heat acclimation ,Heart Rate ,Heart rate ,medicine ,Humans ,Orthopedics and Sports Medicine ,Analysis of variance ,Treadmill ,business ,Exercise - Abstract
Objectives To examine the efficacy of weekly and bi-weekly heat training to maintain heat acclimatization (HAz) and heat acclimation (HA) for 8 weeks in aerobically trained athletes. Design Randomized, between-group. Methods Twenty-four males (mean [m ± standard deviation [sd]; (age, 34 ± 12 y; body mass, 72.6 ± 8.8 kg, VO2peak, 57.7 ± 6.8 mL·kg-1·min-1) completed five trials (baseline, following HAz, following HA (HAz + HA), four weeks into heat training [HTWK4], and eight weeks into HT [HTWK8] that involved 60 min of steady-state exercise (59.1 ± 1.8% vVO2peak) in an environmental laboratory (wet bulb globe temperature [WBGT], 29.6 ± 1.4 °C) on a motorized treadmill. Throughout exercise, heart rate (HR) and rectal temperature (Trec) were recorded. Following HAz + HA, participants were assigned to three groups: control group (HT0), once per week heat training (HT1), and twice per week heat training (HT2). HT involved heated exercise (WBGT, 33.3 ± 1.3 °C) to achieve hyperthermia (38.5-39.75 °C) for 60 min. Repeated measures ANOVAs were used to determine differences. Results HAz + HA resulted in significant improvements in HR (p Conclusions Bi-weekly HT provided clear evidence for the ability to maintain physiological adaptions for 8 weeks following HA.
- Published
- 2022
35. Analysis of climatic factors leading to future summer heatstroke risk changes in Tokyo and Sendai based on dynamical downscaling of pseudo global warming data using WRF.
- Author
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Yamamoto, Miguel, Kasai, Masataka, Okaze, Tsubasa, Hanaoka, Kazumasa, and Mochida, Akashi
- Subjects
- *
HEAT stroke , *DOWNSCALING (Climatology) , *GLOBAL warming , *CLIMATE change , *BOUNDARY value problems - Abstract
Abstract This study aims to clarify the regional characteristics of climate change and its impact on heatstroke risk inside the cities of Tokyo and Sendai, Japan. First, meteorological simulations using the Weather Research and Forecasting model (WRF) were performed. Pseudo global warming data were used as the boundary conditions for WRF simulations for the global-scale current and future climates in the 2000s and 2050s. The increase in wet-bulb globe temperature (WBGT) was larger in Sendai than in Tokyo, and the increase in WBGT in the coastal areas of both cities became larger than that in the inland area. Then, heatstroke risk and incidence rate, which represent the potential risk, were analyzed based on the WBGT distribution. Furthermore, contributions of three types of temperature (wet-bulb, globe, and dry-bulb temperatures) in increasing the WBGT were analyzed in order to clarify the primary meteorological factors for the increase in WBGT in each region. It was found that the wet-bulb temperature is the dominant factor in the increase in WBGT in most regions. Highlights • Future climate and heatstroke risk in Tokyo and Sendai, Japan were predicted. • Air temperature and absolute humidity increased largely in coastal areas. • The increase in heatstroke risk was highest in urban areas. • In coastal areas in Tokyo, heatstroke risk will exist during the 2050s. • Wet-bulb temperature was the dominant factor increasing wet-bulb globe temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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36. Assessing the monthly heat stress risk to society using thermal comfort indices in the hot semi-arid climate of India
- Author
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Pardeep Kumar and Amit Sharma
- Subjects
010302 applied physics ,education.field_of_study ,Dry-bulb temperature ,Wet-bulb globe temperature ,Population ,Equivalent temperature ,Thermal comfort ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Heat stress ,Extreme weather ,Semi-arid climate ,Climatology ,0103 physical sciences ,Environmental science ,0210 nano-technology ,education - Abstract
Extreme weather conditions, especially heatwave, are a threat to society, affecting livability, wellbeing, and social interactions. The present study aims to assess the monthly heat stress in the outdoor environment from 2010 to 2019 in Sonepat's municipality, representing a hot semi-arid climate. The authors applied three heat stress indices, namely, Wet bulb globe temperature (WBGT), Physiological equivalent temperature (PET), and Universal thermal climate index (UTCI), to estimate the grade of heat stress. While calculations, the highest average WBGT was found in July (33.4 ± 0.77 °C), demonstrating July in the “Extreme heat stress” category. The highest mean PET was found in June (42.47 ± 2.34 °C), indicating June in the “Extreme heat stress” category. The highest mean UTCI was found in June (38.58 ± 1.82 °C), demonstrating “Very strong heat stress.” The dry bulb temperature was found to be the most dominant parameter among meteorological parameters promoting extreme heat stress. It was concluded that extreme heat stress was observed in the Pre-monsoon hot weather season and summer monsoon season (especially in June), making the population vulnerable to mortality and morbidity. The findings could provide valuable information to people from various disciplines like Climate scientists, landscape designers, architects, and all relevant stakeholders to develop a heatwave action plan against adverse heat stress.
- Published
- 2022
37. Assessing outdoor thermal comfort conditions at an urban park during summer in the hot semi-arid region of India
- Author
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Amit Sharma and Pardeep Kumar
- Subjects
Dry-bulb temperature ,Urbanization ,Wet-bulb globe temperature ,Global warming ,Microclimate ,Environmental science ,Equivalent temperature ,Thermal comfort ,Socioeconomics ,Arid - Abstract
Urban parks play an essential role in urban settings; significantly contribute to the health of every age group person. Parks provide opportunities for families to connect with nature and breathe in the fresh air. Due to global climate change and increased urbanisation in the past few decades, extreme heat can be experienced in urban areas. Mental and physical health issues arise primarily due to a sedentary lifestyle in cities. Staying at parks for a longer duration could promote stress reduction and perceived physical health. The present study aims to assess the thermal comfort conditions at an urban park in the hot semi-arid climate(BSh) of Haryana, India. The present study investigated the outdoor thermal comfort range and thermal sensations of visitors at a park during the summer season using the onsite monitoring of the microclimate parameters and questionnaire survey in the hot-semi arid region of India. Thermal comfort indices, Physiological equivalent temperature (PET) and Universal Thermal Climate Index (UTCI) and Wet bulb globe temperature(WBGT) have been applied to investigate the outdoor thermal comfort conditions. The seven-point sensation scale has been used to record the visitors' thermal sensations. The results indicated that:1) WBGT was found to be the most suitable index to investigate the OTC conditions. The neutral UTCI, PET, and WBGT ranged within 28.03 °C to 35.6 °C, 24.04 °C to 37.5 °C, and 23.5 °C to 26.1 °C, respectively. 2) The neutral PET ,UTCI, and WBGT were found to be 30.8 °C, 31.8 °C, and 24.8 °C, respectively.3) Dry bulb temperature is the most significant thermal comfort parameter affecting visitors' thermal sensations, followed by mean radiant temperature.4) Thermal comfort indices were found to be most significantly affected by globe temperature. The study's outcome could provide theoretical design reference to urban designers to develop new parks and existing parks, ultimately promoting public health.
- Published
- 2022
38. Long-Term Changes in Summer Extreme Wet Bulb Globe Temperature over China
- Author
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Dongqian Wang and Ying Sun
- Subjects
Human health ,Wet-bulb globe temperature ,Climatology ,Homogenization (climate) ,Humidity ,Environmental science ,Relative humidity ,Mean radiant temperature - Abstract
The wet bulb globe temperature (WBGT) has important implication for human health. Previous studies widely use the monthly data but rarely investigate the extreme WBGT because of data limitation. In this study, we use 6-hourly station data to analyze the changes in the WBGT and three categories (intensity indices, absolute threshold indices and frequency indices) of extreme WBGT indices in summer of 1961–2017. It is found that the spatial distribution of long-term trends in summer mean WBGT is consistent with those in mean temperature. The trend value of WBGT is smaller than the mean temperature, because of the decrease of relative humidity. For the extreme indices, the intensity and frequency of WBGT and fixed threshold indices have changed. The increase of intensity indices and warm WBGT days and nights, and decrease of cold WBGT days and nights have been observed in most China, especially over northwestern China. The number of days with daily maximum WBGT exceeding 31.4°C (WXge31) and minimum WBGT exceeding 27.9°C (WNge29) over southeastern China have increased since 1961. The spread of probability distributions of WXge31, WNge27, warm WBGT days and nights is becoming wider, reflecting increased variability of extreme indices. In addition, urbanization effects on the WBGT are investigated. The impacts of urbanization on most of extreme WBGT indices are not detected, except for absolute thresholds indices. This may be due to the decrease of relative humidity in urban stations, which is almost two times larger than that in rural stations. However, we also note that the homogenization issue of humidity data may affect our conclusion.
- Published
- 2021
39. Effects of Road Components and Roadside Vegetation on Temperature Reduction in Seoul Considering Air, Wet-Bulb Globe, and Surface Temperatures
- Author
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Hyejin Cho
- Subjects
urban road design ,roadside air temperature ,wet-bulb globe temperature ,surface temperature ,roadside vegetation ,median planting ,Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,Building and Construction ,Management, Monitoring, Policy and Law - Abstract
Urbanization has resulted in high temperatures in cities, which are exacerbated by an increase in urban impervious surfaces (road space). This study investigated the effect of urban road characteristics on roadside temperature. Different temperature indices were measured at four sites in Seoul with different road designs by using weather measuring devices and infrared thermal cameras. The differences between air and roadside air temperatures decreased from site 1 (no vegetation) to site 4 (roadside trees and vegetated medians). The analysis results showed that roadside wet-bulb globe and surface thermal temperatures sensitively changed according to road characteristics, unlike air temperature. The lowest temperatures were consistently observed at site 4. This cooling tendency was the strongest in the afternoon, which indicates the effectiveness of vegetation for preventing the commonly observed temperature rise in the afternoon. That is, roadside trees and vegetation in the median strip can prevent temperature rise and contribute to urban temperature reduction. Therefore, more roadside trees and median planting, as well as taller trees and denser vegetation along roads, can be used to provide a greater reduction of roadside temperatures and to improve urban climates.
- Published
- 2022
- Full Text
- View/download PDF
40. Investigating Future Urbanization’s Impact on Local Climate under Different Climate Change Scenarios in MEGA-urban Regions: A Case Study of the Pearl River Delta, China
- Author
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Pak Shing Yeung, Jimmy Chi-Hung Fung, Chao Ren, Yong Xu, Kangning Huang, Jiye Leng, and Michael Mau-Fong Wong
- Subjects
urban climate ,WRF ,Land use land cover ,wet-bulb globe temperature ,thermal comfort ,future urbanization prediction ,Meteorology. Climatology ,QC851-999 - Abstract
Urbanization is one of the most significant contributing factors to anthropogenic climate change. However, a lack of projected city land use data has posed significant challenges to factoring urbanization into climate change modeling. Thus, the results from current models may contain considerable errors in estimating future climate scenarios. The Pearl River Delta region was selected as a case study to provide insight into how large-scale urbanization and different climate change scenarios impact the local climate. This study adopts projected land use data from freely available satellite imagery and applies dynamic simulation land use results to the Weather Research and Forecasting Model (WRF). The simulation periods cover the summer periods in 2010 and 2029–2031, the latter of which is averaged to represent the year 2030. The WRF simulation used the observed local climate conditions in 2010 to represent the current scenario and the projected local climate changes for 2030 as the future scenario. Under all three future climate change scenarios, the warming trend is prominent (around 1–2 °C increase), with a widespread reduction in wind speed in inland areas (1–2 ms−1). The vulnerability of human health to thermal stress was evaluated by adopting the wet-bulb globe temperature (WBGT). The results from the future scenarios suggest a high public health risk due to rising temperatures in the future. This study provides a methodology for a more comprehensive understanding of future urbanization and its impact on regional climate by using freely available satellite images and WRF simulation tools. The simulated temperature and WBGT results can serve local governments and stakeholders in city planning and the creation of action plans that will reduce the potential vulnerability of human health to excessive heat.
- Published
- 2020
- Full Text
- View/download PDF
41. Thermal comfort provided by different shading structures in free-range systems in Brazilian savanna
- Author
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João Victor do Nascimento Mós, Evandro Menezes de Oliveira, Antonio José Steidle Neto, Vinícius Machado dos Santos, Luci Sayori Murata, Sheila Tavares Nascimento, and Bruno Emanoel Teixeira
- Subjects
Atmospheric Science ,Heat index ,Ecology ,Health, Toxicology and Mutagenesis ,Wet-bulb globe temperature ,Temperature ,Microclimate ,Thermal comfort ,Humidity ,Atmospheric sciences ,Grassland ,Wind speed ,Trees ,Environmental science ,Shading ,Shortwave radiation ,Mean radiant temperature - Abstract
This work aimed to evaluate the thermal comfort provided by shading structures in free-range systems under a tropical environment, based on microclimate variables of nets with different materials. During the experiment, the unshading area; the natural shading of a native tree species to the Brazilian Savanna; and the artificial 80% shadings nets: black polypropylene, heat-reflective aluminized, and association of both were evaluated. The shading structures were analyzed in paddocks at the Água Limpa Farm from the University of Brasília, where dry-bulb, wet-bulb, black globe temperatures, and wind speed were collected for the micrometeorological characterization from 8:00 am to 4:00 pm. From the temperatures, the vapor pressures and the humidities were calculated. The shortwave radiation was calculated through the sum of direct, diffuse, and reflected radiations. The mean radiant temperature, radiant heat load, and black globe temperature and humidity index were calculated. The internal and external surface temperatures of the nets and the soil temperature were measured every 30 min. The data were analyzed with aid of the statistical analysis system. The air temperature varied according to the shortwave radiation, from 25.6 °C at 8:00 am to 29.6 °C at 1:00 pm, with a decrease over the hours. Despite the air temperature of the trees showed the lowest average, the nets association structure was the most reduced all the thermal comfort indexes. The heat-reflective net presented the lowest soil temperature at all hours (under 26.1 °C). In general, the shadings proved to be efficient in promoting thermal comfort in free-range systems.
- Published
- 2021
42. Outdoor performance of the black globe temperature sensor on a hot and humid tropical region
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Angela Dissegna, Juan Angel Acero, Yon Sun Tan, Leslie K. Norford, and Adrian Tan
- Subjects
Convection ,Wet-bulb globe temperature ,Elevation ,Thermal comfort ,General Medicine ,Heat transfer coefficient ,Atmospheric sciences ,Overcast ,Thermometer ,Environmental Chemistry ,Environmental science ,Mean radiant temperature ,Waste Management and Disposal ,Water Science and Technology - Abstract
A crucial variable to evaluate thermal comfort is the mean radiant temperature (Tmrt). In this paper we evaluate the performance of the 150 mm black globe thermometer to provide reliable Tmrt values for outdoor settings in Singapore. Accurate Tmrt values are calculated by the method of integral radiation measurements. Based on these, the mean convection coefficient of the black globe has been re-calibrated. Results show an improvement in the estimation of Tmrt with the new coefficient in comparison with the default version suggested in ISO7726:1998. Increasing the averaging periods of the measured variables improved the performance of the derived mean convective coefficients to estimate Tmrt. During clear skies day and for 10-min averaged data, RMSE for Tmrt reduce to 3.9 °C (7.4 °C for ISO7726:1998 coefficient) with an overestimation on high incoming solar radiation periods and an underestimation during the morning and evening (low solar elevation). During overcast dry conditions an underestimation of Tmrt is also expected which is higher in the rain/wet periods. The mean convective coefficient presented in this work can provide improved estimations of Tmrt relevant for outdoor thermal comfort studies in hot and humid tropical climates like Singapore.
- Published
- 2021
43. Investigation of Thermal Comfort Changes Using Summer Simmer Index (SSI): A Case Study in Different Climates of Iran
- Author
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Gholamabbas Fallah Ghalhari, Mehdi Asghari, and Hamidreza Heidari
- Subjects
Index (economics) ,Wet-bulb globe temperature ,Climatology ,Global warming ,Environmental science ,Thermal comfort - Abstract
Objective: This study aimed to assess the thermal comfort trend using a metrological parameter based on the Summer Simmer Index (SSI), for different climates of Iran between 1985 and 2014. Methods: This is a Time-series study. The new SSI was calculated using metrological data in a 30 year- period for illustrating the changes to the thermal comfort or discomfort level through summer months in different climates of Iran. Mann- Kendall test and Sen's Slope were used to compare the upward or downward trend of the index during this period. Results: The worst thermal condition was observed in the southern and central regions of the country. A few stations were put in comfort zone (77≤SSI°F). The fluctuations of SSI were not considerable during the study period (P Conclusion: Based on the results obtained in this study, which has been investigated in Iran for a long period of time, considering intrinsic features of the SSI index, such as ease of calculation and interpretation and also the possibility of calculating the index using daily reported meteorological data, the use of SSI as a screening index of thermal stress in order to adopt preventive policies in outdoor settings in climates of Iran is recommended.
- Published
- 2021
44. Quantifying the impact of heat on human physical work capacity; part III: the impact of solar radiation varies with air temperature, humidity, and clothing coverage
- Author
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Josh Foster, James W. Smallcombe, George Havenith, Andreas D. Flouris, Ollie Jay, Lars Nybo, and Simon Hodder
- Subjects
Male ,Atmospheric Science ,Work (thermodynamics) ,Hot Temperature ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,Wet-bulb globe temperature ,Performance ,Radiation ,Atmospheric sciences ,Heat Stress Disorders ,01 natural sciences ,Heat stress ,Clothing ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Thermal ,Faculty of Science ,Humidex ,Humans ,Relative humidity ,0105 earth and related environmental sciences ,Sunlight ,Original Paper ,Labor capacity ,Ecology ,Temperature ,Humidity ,030229 sport sciences ,13. Climate action ,UTCI ,Environmental science ,WBGT ,Skin Temperature - Abstract
Heat stress decreases human physical work capacity (PWC), but the extent to which solar radiation (SOLAR) compounds this response is not well understood. This study empirically quantified how SOLAR impacts PWC in the heat, considering wide, but controlled, variations in air temperature, humidity, and clothing coverage. We also provide correction equations so PWC can be quantified outdoors using heat stress indices that do not ordinarily account for SOLAR (including the Heat Stress Index, Humidex, and Wet-Bulb Temperature). Fourteen young adult males (7 donning a work coverall, 7 with shorts and trainers) walked for 1 h at a fixed heart rate of 130 beats∙min−1, in seven combinations of air temperature (25 to 45°C) and relative humidity (20 or 80%), with and without SOLAR (800 W/m2 from solar lamps). Cumulative energy expenditure in the heat, relative to the work achieved in a cool reference condition, was used to determine PWC%. Skin temperature was the primary determinant of PWC in the heat. In dry climates with exposed skin (0.3 Clo), SOLAR caused PWC to decrease exponentially with rising air temperature, whereas work coveralls (0.9 Clo) negated this effect. In humid conditions, the SOLAR-induced reduction in PWC was consistent and linear across all levels of air temperature and clothing conditions. Wet-Bulb Globe Temperature and the Universal Thermal Climate Index represented SOLAR correctly and did not require a correction factor. For the Heat Stress Index, Humidex, and Wet-Bulb Temperature, correction factors are provided enabling forecasting of heat effects on work productivity. Supplementary Information The online version contains supplementary material available at 10.1007/s00484-021-02205-x.
- Published
- 2021
45. Deforestation and climate change are projected to increase heat stress risk in the Brazilian Amazon
- Author
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Beatriz Fátima Alves de Oliveira, Marcus Jorge Bottino, Carlos A. Nobre, and Paulo Nobre
- Subjects
QE1-996.5 ,Natural resource economics ,Amazon rainforest ,Wet-bulb globe temperature ,Deforestation and climate change ,Climate change ,Geology ,Environmental sciences ,Effects of global warming ,Deforestation ,General Earth and Planetary Sciences ,Environmental science ,Climate model ,Land use, land-use change and forestry ,GE1-350 ,sense organs ,geographic locations ,General Environmental Science - Abstract
Land use change and deforestation can influence local temperature and climate. Here we use a coupled ocean-atmosphere model to assess the impact of savannization of the Amazon Basin on the wet-bulb globe temperature heat stress index under two climate change scenarios (RCP4.5 and RCP8.5). We find that heat stress exposure due to deforestation was comparable to the effect of climate change under RCP8.5. Our findings suggest that heat stress index could exceed the human adaptation limit by 2100 under the combined effects of Amazon savannization and climate change. Moreover, we find that risk of heat stress exposure was highest in Northern Brazil and among the most socially vulnerable. We suggest that by 2100, savannization of the Amazon will lead to more than 11 million people will be exposed heat stress that poses an extreme risk to human health under a high emission scenario. Complete savannization of the Amazon Basin would enhance the effects of climate change on local heat exposure and pose a risk to human health, according to climate model projections.
- Published
- 2021
46. The effects of hydration status and ice-water dousing on physiological and performance indices during a simulated soccer match in the heat
- Author
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Courteney L. Benjamin, Erica M. Filep, Cody R. Butler, Margaret C. Morrissey, Rebecca L. Stearns, Douglas J. Casa, and Yasuki Sekiguchi
- Subjects
medicine.medical_specialty ,Hot Temperature ,Wet-bulb globe temperature ,Physical Therapy, Sports Therapy and Rehabilitation ,Athletic Performance ,Heat Stress Disorders ,Body Mass Index ,Young Adult ,03 medical and health sciences ,Cognition ,0302 clinical medicine ,Heart Rate ,Soccer ,Heart rate ,Reaction Time ,Humans ,Medicine ,Orthopedics and Sports Medicine ,030212 general & internal medicine ,Hydration status ,Cross-Over Studies ,business.industry ,Ice ,Repeated measures design ,Humidity ,030229 sport sciences ,Ice water ,Sprint ,Cryotherapy ,Physical therapy ,Fluid Therapy ,Analysis of variance ,business ,Anaerobic exercise ,Body Temperature Regulation - Abstract
Objectives To assess the effects of hydration status and ice-water dousing on physiological and performance parameters. Design Randomized, crossover. Methods Twelve athletes (mean[M] ± standard deviation[SD]; age, 20 ± 1 years; height, 174 ± 8 cm; body mass, 72.1 ± 11.0 kg; VO2max 53.9 ± 7.3 mL⋅kg−1⋅min−1) completed four trials (euhydrated without dousing, hypohydrated without dousing, euhydrated with dousing, and hypohydrated with dousing), which involved intermittent treadmill running (five 15-minute bouts) in the heat (M ± SD; ambient temperature, 34.7 ± 2.1 °C; relative humidity, 46 ± 3%; wet-bulb globe temperature, 28.0 ± 0.4 °C). Participants also completed four cognitive, power, agility, reaction time, and repeated sprint performance tests throughout each trial. Heart rate (HR) and rectal temperature (Trec) were measured continuously. Repeated measures ANOVAs were performed to assess differences between physiological and performance variables. Alpha was set at ≤0.05, a priori. Data are reported as mean difference ± standard error (MD ± SE). Results HR was significantly lower in euhydrated trials compared to hypohydrated trials, irrespective of dousing (8 ± 2 bpm; p = 0.001). Dousing did not significantly impact HR (p = 0.455) and there was no interaction between hydration and dousing (p = 0.893). Trec was significantly lower in euhydrated trials compared to hypohydrated trials (0.39 ± 0.05 °C, p Conclusions Athletes should aim to maintain euhydration during exercise in the heat for improved physiological function and cooling with ice-water dousing elicits additional performance benefits.
- Published
- 2021
47. From theory to practice: operationalizing a climate vulnerability for sport organizations framework for heat hazards among US High schools
- Author
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Douglas J. Casa, William M. Adams, Samantha E. Scarneo-Miller, and Andrew Grundstein
- Subjects
Hot Temperature ,Climate Change ,Wet-bulb globe temperature ,Vulnerability ,Physical Therapy, Sports Therapy and Rehabilitation ,Heat Stress Disorders ,Sports Medicine ,Risk Assessment ,Occupational safety and health ,03 medical and health sciences ,0302 clinical medicine ,Environmental health ,Humans ,Orthopedics and Sports Medicine ,030212 general & internal medicine ,Schools ,Operationalization ,biology ,Athletes ,030229 sport sciences ,biology.organism_classification ,Policy analysis ,Hazard ,Organizational Policy ,United States ,Athletic Injuries ,Observational study ,Psychology - Abstract
Background Sport 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. Objectives We quantify heat vulnerability of state-level requirements for health and safety standards affecting United States (US) high school athletes as a case study. Design Observational. Methods We 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 ( 9)]. Results Across 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. Conclusions The 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.
- Published
- 2021
48. Projected Changes in Extreme High Temperature and Heat Stress in China.
- Author
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Liu, Xingcai, Tang, Qiuhong, Zhang, Xuejun, and Sun, Siao
- Abstract
High temperature accompanied with high humidity may result in unbearable and oppressive weather. In this study, future changes of extreme high temperature and heat stress in mainland China are examined based on daily maximum temperature (T
x ) and daily maximum wet-bulb globe temperature (Tw ). Tw has integrated the effects of both temperature and humidity. Future climate projections are derived from the bias-corrected climate data of five general circulation models under the Representative Concentration Pathways (RCPs) 2.6 and 8.5 scenarios. Changes of hot days and heat waves in July and August in the future (particularly for 2020-50 and 2070-99), relative to the baseline period (1981-2010), are estimated and analyzed. The results show that the future Tx and Tw of entire China will increase by 1.5-5°C on average around 2085 under different RCPs. Future increases in Tx and Tw exhibit high spatial heterogeneity, ranging from 1.2 to 6°C across different regions and RCPs. By around 2085, the mean duration of heat waves will increase by 5 days per annum under RCP8.5. According to Tx , heat waves will mostly occur in Northwest and Southeast China, whereas based on Tw estimates, heat waves will mostly occur over Southeast China and the mean heat wave duration will be much longer than those from Tx . The total extreme hot days (Tx or Tw > 35°C) will increase by 10-30 days. Southeast China will experience the severest heat stress in the near future as extreme high temperature and heat waves will occur more often in this region, which is particularly true when heat waves are assessed based on Tw . In comparison to those purely temperature-based indices, the index Tw provides a new perspective for heat stress assessment in China. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
49. A new evaluation index for indoor hot environment in naturally ventilated building with hot surface
- Author
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Yi Wang, Xiaozhou Wu, Yashan Cui, and Jie Gao
- Subjects
Index (economics) ,Wet-bulb globe temperature ,0211 other engineering and technologies ,Public Health, Environmental and Occupational Health ,Environmental science ,021108 energy ,02 engineering and technology ,Air movement ,010501 environmental sciences ,Atmospheric sciences ,01 natural sciences ,0105 earth and related environmental sciences - Abstract
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.
- Published
- 2021
50. Estimating the magnitude and risk associated with heat exposure among Ghanaian mining workers
- Author
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Victor Fannam Nunfam, Jacques Oosthuizen, Kwasi Frimpong, Eddie J. B. van Etten, and Kwadwo Adusei-Asante
- Subjects
030203 arthritis & rheumatology ,Atmospheric Science ,Adaptive capacity ,010504 meteorology & atmospheric sciences ,Ecology ,Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,Wet-bulb globe temperature ,Productive capacity ,01 natural sciences ,Occupational safety and health ,03 medical and health sciences ,0302 clinical medicine ,Work (electrical) ,Environmental health ,Workforce ,Psychological resilience ,Business ,Social determinants of health ,0105 earth and related environmental sciences ,media_common - Abstract
Many occupational settings located outdoors in direct sun, such as open cut mining, pose a health, safety, and productivity risk to workers because of their increased exposure to heat. This issue is exacerbated by climate change effects, the physical nature of the work, the requirement to work extended shifts and the need to wear protective clothing which restricts evaporative cooling. Though Ghana has a rapidly expanding mining sector with a large workforce, there appears to be no study that has assessed the magnitude and risk of heat exposure on mining workers and its potential impact on this workforce. Questionnaires and temperature data loggers were used to assess the risk and extent of heat exposure in the working and living environments of Ghanaian miners. The variation in heat exposure risk factors across workers’ gender, education level, workload, work hours, physical work exertion and proximity to heat sources is significant (p
- Published
- 2021
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