An environmental stress index (ESI) as a substitute for the wet bulb globetemperature (WBGT)

The purpose of this study was to develop a new environmental stress index ( ESI) based on different parameters relating to heat stress. Meteorological measurements were taken in three climatic zones (hot/wet, hot/dry, and extr emely hot/dry) for 60 days, and a new stress index based on these databases was developed as follows: ESI = 0.63T(a) - 0.03RH+0.002SR+0.0054(T-a. RH)-0.073(0.1+SR)(-1), where T-a is the ambient temperature (C). RH the relative humidity (%), and SR the solar radiation (W.m(-1)). The correlation coefficients between ESI and wet bulb globe temperature (WBGT) were very high (R-2>0.981). Therefor e, we conclude that ESI, based on fast response and the more commonly used accurate climatic microsensors (T-a, RH, SR) which can be combined in a sma ll portable device, has the potential to be a practical alternative to the WBGT. (C) 2001 Elsevier Science Ltd. All rights reserved.