Hamed Jalilian; Ahmad Soltanzadeh; Abdolhalim Rajabi; Hamidreza Heidari
Abstract
Background: This study aims to assess the consistency of the newly developed Outdoor Environmental Heat Index (OEHI) with existing environmental and physiological heat indices in low thermal stressconditions. This comparison is necessary due to potential variations in the performance of a heat stress ...
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Background: This study aims to assess the consistency of the newly developed Outdoor Environmental Heat Index (OEHI) with existing environmental and physiological heat indices in low thermal stressconditions. This comparison is necessary due to potential variations in the performance of a heat stress index when applied in conditions different from those for which it was developed.Methods: Two current and valid outdoor heat indices, including Wet Bulb Globe Temperature (WBGT) and Humidex (HD), were used in a descriptive-analytical study to compare the results obtained by OEHI and other indices in evaluating the same condition. Furthermore, the authors considered tympanic temperature as a physiological response to heat and assessed the work environment of 63 outdoor workers at three-hour intervals during the workday.Results: The highest coefficient of determination was assigned to OEHI and Humidex index (R2>0.99, P<0.0001). Regarding the correlation between the OEHI and the WBGT index, this correlation with and without considering the time of the measurement was higher than 0.98. Comparisons for the correlations of thermal indices with tympanic temperature showed poor and significant relations between thermal indices and tympanic temperature (R2<0.19, P<0.0001).Conclusion: OEHI can evaluate the thermal condition in low heat stress conditions, similar to other current and valid thermal stress indices, including WBGT and Humidex. The OEHI shows a better correlation with the Humidex than the WBGT index. However, due to the poor correlation observed between OEHI and tympanic temperature in low-stress conditions, it is recommended to use this index just as a screening index to estimate thermal environmental conditions.
Farideh Golbabaei; Hamidreza Heidari; Aliakbar Shamsipour
Abstract
Background: This study aimed to illustrate the applicability of the Humidex index for assessment of outdoor thermal environments in a wide range of weather conditions in different climates in Iran.
Study Design: This is a cross-sectional study.
Methods: Both field measurements (1452 measurements) ...
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Background: This study aimed to illustrate the applicability of the Humidex index for assessment of outdoor thermal environments in a wide range of weather conditions in different climates in Iran.
Study Design: This is a cross-sectional study.
Methods: Both field measurements (1452 measurements) and the long-term meterological data (between 1965 and 2009) were used in this research. After determining the appropriateness of correlation coefficients between these two types of data, only meteorological stations data were used to generalize the results to climatic regions. For this purpose, Arc/GIS 10.2 software was used.
Results: The results showed three levels of comfort including safe, caution and stress regions by graphical maps. The results showed that the center and south of the country, especially at the middle and the end of the shift hours, experienced more thermal stress in summer months (ranging from 39.60±1.07 to 49.29±2.13ºC for central areas and ranging from 47.76±2.59to 57.71±1.65ºC for southern areas. In the northern regions, most of the measurements in different stations and time periods at spring were in caution condition and less than 1% of them experienced stress conditions.
Conclusion:
The dependence of this index on the minimum metrological parameters (temperature and humidity), which are easily measured and reported daily in meteorological stations, and its non-dependence on the globe temperature, which is an unusual parameter in the measured metrological parameters, can be used as advantages of the humidex for assessment of the heat stress conditions in outdoor environments in different climates.
