Feasibility of Relative Strain Index (RSI) for the Assessment of Heat Stress in Outdoor Environments: Case Study in Three Different Climates of Iran

Abstract

Objectives: Different indices are used to evaluate heat stress in outdoor environments. This study was aimed at examining the applicability of the Relative Strain Index (RSI) to the assessment of heat stress in several climates of Iran. Methods: Based on the Köppen classification, three different climates were studied. Arak, Bandar Abbas, and Sari were selected as representative of semi-arid and cold climates, hot and dry, and Mediterranean, respectively. The data recorded by the meteorological organization, including air temperature, relative humidity and air velocity were surveyed during 15-year period in three different climates. The RSI index was calculated by the formula. Also, the Wet Bulb Globe Temperature (WBGT) index was computed using a model presented by the Australian Bureau of Meteorology (ABM). Data were analyzed using SPSS v.22, descriptive statistics, Pearson correlation coefficient, and linear regression. Results: The mean RSI index in summer of the 15 years in Arak was 0.033 ± 0.33, in Bandar Abbas 0.54 ± 0.6 and for Sari was 0.17 ± 0.05. A high correlation was found between environmental variables and RSI index in three different climates. As well, there was a positive and significant correlation between both RSI and WBGT indices in three different climates (R2>0.96). Conclusion: The RSI index is a simple and empirical index and can be used for the evaluation of heat stress along with other indices. The index estimates the situation more than expected to be stressful in warm and dry conditions. So, it is not a useful index for hot and dry climates such as Bandar Abbas.

The Influence of Urban Climate on Bioclimatic Conditions in the City of Iași, Romania

“…For December and January the UHI imposes less "extremely cold" conditions in the urban areas. This confirms the fact that the urban climate has positive effects on the human bioclimatological comfort during winter, for Ias , i city as well [9,47].…”

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“…RSI renders the comfort level according to the following conditions: internal heat production 100 W/m 2 , air movement less than 1 ms −1 and no solar radiation income. RSI is calculated using air temperature values (t/ • C) and water vapor pressure (e/hPa) [46,47]) and is mathematically expressed as follows:…”

Trend analysis of Humidex as a heat discomfort index using Mann-Kendall and Sen’s slope estimator statistical tests

“…It may also cause shortness of breath and tachycardia. Heat exposure contributes to anger and aggressive behavior which increase heart rate and, in conjunction with tightness of the coronary artery, can increase the risk of heart attacks (13,14). The rise in deaths during heatwaves is mostly attributed to cardiovascular (13%-90%) and cerebrovascular disorders (6%-52%) especially among older individuals (15,16).…”

Spatio-Temporal Evolution of the Thermo-Hygrometric Index (THI) during Cold Seasons: A Trend Analysis Study in Iran

“…Climatic conditions are one of the most important and influential factors in various aspects of human life, especially in high-traffic urban areas [14]. Establishing a thermal balance between the human body and its surrounding environment is one of the primary needs to ensure a person's health and comfort.…”