GREEN INFRASTRUCTURE CHARACTERIZATION TO IMPROVE AIR QUALITY AND THERMAL ENVIRONMENT

Abstract

According to world population predictions, nearly all of the world's new megacities (defined as having a population of more than 10 million people) are located in the developing world. In recent decades, rapid unplanned urbanisation around the world has caused unprecedented anthropogenic stress in the urban environment, affecting air quality and rising temperatures in highly developed industrial areas and densely populated regions of developed and developing countries. Megacities usually have significant levels of PM10 and PM2.5 from fossil fuel combustion, fugitive dust, biomass burning from industry, transportation, and densely populated areas. According to the WHO, more than 4 million people die annually from outdoor air pollution (PM), accounting for 11.65% of worldwide deaths and 1% of global GDP. Recently, air pollution was placed first among environmental concerns. Similarly, due to changes in urban micro-climate conditions, the urban heat island (UHI) phenomenon intensifies in megacities. IPPC 2022 predicted a rise in hot days in metropolitan areas, especially in the tropics. With 1.5 degrees Celsius warming, 14% of Earth's population would suffer extreme heatwaves every five years, whereas at 2 degrees Celsius, it would impact around 37% of the population. By the year 2100, urbanisation-induced climate change will increase heat stroke and death tolls by 50 times. Air pollution and rising temperatures in Indian cities have become major environmental challenges in recent decades. India ranked lowest in the 2022 World Environment Day Environmental Performance Index (EPI) report. India was the sixth-most polluted nation in 2021, and Delhi was ranked top in India, according to a report by Swiss PM concentration provider IQAir. PM pollution costs 5.4% of GDP and causes the deaths of 1 million people annually in India. Extreme heat events are predicted for south Asian regions in the UN Intergovernmental Panel on Climate Change's 6th assessment report. The prediction expects 4000 heat-related fatalities in South Asia, especially in India and Pakistan. According to the India Meteorological Department and the Indian Institute of Tropical Meteorology (Pune), India's temperature has climbed beyond 2°C since 1900, whereas the global average has risen 1.3°C. Researchers have shown various ways to manage PM pollution in Indian cities, such as the use of cleaner energy, emission reduction, and regional or national cooperation. There is rising interest in how nature-based urban green infrastructure (UGI) landscape composition and configuration impact ecosystem services, including pollution management and urban heat hazards. As per many studies, Green Infrastructure (GI) may lower PM concentration and urban heat via deposition, dispersion, shade, ventilation, and evapotranspiration. The name Green Infrastructure (GI) is new, although its concept is 150 years old in planning and conservation.