Occupational Medicine & Health Affairs
Open Access

Abstract

Objectives: The worldwide facts show that climate is changing increasingly over the past decades. Accordingly, the changes in temperature and precipitation, not only affect the population health but also, it causes labor?s productivity loss. Productivity loss and low activity is a natural reaction of the body to reduce internal heat generation and temperature and its compensatory mechanism for balancing the body?s temperature. The aim of this study is the estimation of productivity loss due to exposure to heat stress in Iran?s outdoor workers. Methods: This study was done from early spring 2012 to late spring 2013. In this study all the outdoor workers employed in various occupational groups including farmers, fisheries, fishermen, ranchers, contractors and other outdoor businesses were considered. Jobs are classified according to worker?s metabolic rate as mentioned in ISO 8996 standard. In order to estimate the amount of heat exposure in outdoor workers, the wet bulb globe temperature index was used. WBGT estimation was done based on data from 83 meteorological synoptic stations in 30 provinces by using the proposed formula by Australian metrological Organizations. In this study it was assumed that all the workers are wearing light clothes so its effect on WBGT is not considered. All the data using Inverse Distance Weighting was interpolated by using GIS software. WBGT maps were also demonstrated in whole range of the country and the maps were presented in 4 different seasons. Productivity loss due toexposure to heat was also calculated by Kjellstrom method. Result: It was found that, there was a higher WBGT level in summer compared with other seasons, and provinces of Bushehr(38.87?C)Khozestan (38.54?C) and Sistan and Balouchestan(32.51?C) showed the highest WBGT in Iran. However provinces of Chaharmalbakhtiyari (26.55?C) and Azarbayejan Gharbi (27.25?C) showed the lowest WBGT in Iran. It was also observed that the highest productivity loss occurs in summer and 60.6% of provinces showed a heavy productivity loss in this season.The amount of outdoor workers productivity loss due to heat exposure was found to be nearly 100% in Khuzestan and Bushehr. According to the results, productivity loss increases as we move from provinces located in North West to South East. Conclusion: According to the present research, the average productivity loss especially in summer is found to be high in Iran and this is because of Iran?s specific climatic conditions and distribution of national employment. Productivity loss due to heat exposure and the growing trend of temperature rise in the coming years is undeniable. Regarding to the important role of outdoor workers and their extend distribution in Iran, this fact seems very important. Therefore further studies and adaptation solutions to improve compliance and reduction of the sensitivity from the direct exposure to the solar radiation is very important and necessary.

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