ISSN(Online) : 2319-8753 ISSN (Print) : 2347-6710 International Journal of Innovative Research in Science, Engineering and Technology (An ISO 3297: 2007 Certified Organization) Vol. 5, I ssue 3, March 2016 Copyright to IJIRSET DOI:10.15680/IJIRSET.2016.0503044 2998 Assessment of Heat Stress on Open Field Workers at Four Indian Coastal Stations G. Biswas 1 , A. Bhattacharya 2 , M. Ali 3 and R. Bhattacharya 4 Research Scholar, Department of Environmental Science, University of Kalyani, Nadia, West Bengal, India 1 Medical student, Mata Gujri Memorial Medical College, Kishanganj, Bihar, India 2 Research Scholar, Department of Environmental Science, University of Kalyani, Nadia, West Bengal, India 3 Professor, Department of Environmental Science, University of Kalyani, Nadia, West Bengal, India 4 ABSTRACT: Due to global warming, increase in air temperature is a growing concern at present. This rise in temperature may cause mild to severe thermal discomfortability and heat related hazards mostly for the people who are engaged in outside activity throughout the day. The present study shows the distribution of thermal loads over four coastal stations of India viz, Digha (22.38º N, 87.32º E), Visakhapatnam (17.68º N, 83.21º E), Thiruvananthapuram (8.48º N, 76.95º E) and Goa (15.49º N, 73.82º E). In this present study Wet Bulb Globe Temperature (WBGT) is used to estimate the thermal stresses by using last ten years’ meteorological data. It is observed that 36%, 43%, 55% and 35% days of summer months are fall in the partial discomfort category (II) for Digha, Visakhapatnam, Thiruvananthapuram and Goa respectively. It is interesting to note that 2.53% and 6.82% days of winter season of Goa and Thiruvananthapuram are also in the same zone. Severe stresses are observed in the East coast during summer and monsoon months. A positive trend varying from 0.30ºC to 0.45º C per year is observed for all the Coastal stations except Thiruvananthapuram. Regional based Discomfort Index (DI) scale is also proposed in this study. KEYWORDS: Heat stress, Wet Bulb Globe Temperature, Discomfort Index, Thermal discomfort, Coastal stations I. INTRODUCTION Climate change which increases the global temperature is one of the most concern subjects now a day. Rapid urbanization and industrialization alters radiation balance which changes the air flow and turbulence. Moreover increased air pollution by human activities cumulatively rise the surrounding air temperature [1]. This rise in temperature leads to thermal discomfort and several heat related illness such as heat rashes, heat cramps, heat exhaustion and even sever heat stroke. Thermal stress affects the people most who are exposed directly to the sun such as soldiers, athletes, farmers, travellers and often open field workers [2, 3]. As heat stress directly affects the individuals’ health, it also reduces the worker’s performance and productivity [4] which may have negative impact on socio-economic status and economic development. Comfort is a sensation and thermal comfort is the pleasant state of mind of an individual to his/her surrounding thermal environment [5, 6]. This thermal sensation depends upon two factors such as environmental factors viz, air temperature, radiant heat, wind speed, relative humidity and behavioural factors viz, total metabolic rate, clothing [7]. As this thermal comfort is also an acceptable temperature zone, it ranges 23⁰C to 27⁰C during summer and 20⁰C to 25⁰C during winter [8]. Thermal stress is the balance between a worker’s net thermal load (by the work and environment) and the capacity of eliminating the heat. In the last few decades rise in global mean temperature with very fast urban and industrial development lead to increase the heat stress mostly during the summer season [9, 10, 11, 12]. Workers from construction industries, agricultural sectors, pottery industry, power plant and different unorganised sectors are mostly affected by the summer thermal stress. Active researches are going on throughout the world to indexing the thermal stress and more accurately grade it according to different climate zone [13, 14, 15, 16, 17]. In this paper, an attempt is made to evaluate the thermal comfortability of four Indian coastal regions to suggest scientific work-rest plan throughout the year for outdoor workers with Discomfort Index scale on regional basis.