Heat-related public health impacts based on the WBGT index in Colombo, Sri Lanka

Abstract

Human health, energy and comfort are determined by climate remained in the physical environment. All living beings are sensitive to the environment in physical and psychological terms. Climate change, urbanization, and an aging population create a perfect storm of risks to global health, particularly from the urban heat. Heat exhaustion, heat pyrexia, heat syncope, and heat cramps were found to be the most common effects of heat stress. Colombo is selected as the study area of the research and it is the commercial capital and largest city of Sri Lanka by population with the process of urbanization. This study tried to analyze heat stress and public health effects in Colombo, based on the secondary data (Temperature and Relative Humidity (RH%)) acquired from the Department of Meteorology in Colombo in 2008 to 2018. Then calculated the Wet-Bulb Globe Temperature (WBGT) index was introduced by the Australian Bureau of Meteorology (ABM) to examine heat waves and their impacts on public health. That requires only water vapour pressure (ρ), air temperature (Ta), and RH% as input. Throughout the year Colombo has not come under the “Comfortable” category (WBGT: ≤ 27.7) of the thermal sensation. Because the whole year's temperature is not below 27oC and RH% also fluctuates between 75% and 84%. As a result of that, for the whole year, the WBGT index value is 30.0 ≤. Therefore, throughout the year “Heat cramps and heat exhaustion are possible”. Especially in the period of the First Inter Monsoon (FIM) and Second Inter Monsoon (SWM), the city belongs to the “Very severe stress” (WBGT: ≥32.2) category with “Heatstroke highly likely”. When concluding the all facts, Colombo is a stressful city with several possible heat hazards. It is imperative to assess these risks and respond effectively