Impact of urbanization on the thermal comfort conditions in the hot humid city of Chennai, India

Urbanization results in the phenomenal shift of human population towards urban centers, affecting the urban environment quality and standard of life. Urban growth along with the increased impervious built infrastructure, determines the climate in cities resulting in a distinct climatic condition termed the “Urban Heat Island”. Tropical cities characterized by high temperatures and humidities, suffer extensively due to the urban heat island effect and urban climate studies are crucial in improving the thermal comfort outdoors. Therefore, this paper aims to analyze the impact of urbanization on thermal comfort conditions in the hot humid city of Chennai, India. Although, urban climate studies have gained significant attention globally, in India, climate studies are restricted to the investigations of the intensity of urban heat island and are primarily conducted by the India Meteorological Department. Scientific research correlating the link between climate and comfort trends are often neglected, but are essential in improving the comfort conditions in urban areas. The impact of urbanization on climate trends were studied using the historic climate records from the two meteorological stations, Nungambakkam and Meenambakkam for 20 year period from 1988 to 2008. The thermal comfort trends in Chennai Metropolitan Area were then analyzed in terms of Temperature Humidity Index and Relative Strain Index. The study revealed significant decrease in the thermal comfort conditions due to urbanization. Also, the results indicated the increasing discomfort in daytime temperatures over years. The climate aspects in planning regulations are generally ignored due to the lack of scientific assessments. This study was aimed at providing the scientific knowledge on the link between urbanization and thermal comfort and would aid in evolving climate-responsive design guidelines.