Air Pollution in Mega Cities: A Case Study of Istanbul

The main objective of this chapter is to enhance our understanding of the polluted atmosphere in megacities, with respect to the emission characteristics, climate, population and specific meteorological conditions that are leading to episodes.Therefore, the chapter will provide state-of-the-art reviews of air pollution sources and air quality in some selected megacities, particularly Beijing, Cairo, Delhi and Istanbul.Furthermore, a detailed analysis of emission sources, air quality, mesoscale atmospheric systems and local meteorology leading to air pollution episodes in Istanbul will be extensively presented.The world population is expected to rise by 2.3 billion, passing from 6.8 billion to 9.1 billion in between 2009 and 2050 (UN Report, 2010).Additionally, population living in urban areas is projected to gain 2.9 billion from 3.4 to 6.3 billion in this period.However, during the industrial revolution years, only about 10% of the total population lived in the cities.As an example, in 1820, which is the beginning times of the United States (US) transformation from rural to urban, the great majority of the population lived in rural areas of US (about 96%) (Kim, 2007).Today, according to UN Report the world population in urban areas has reached to 50.5%.In other words, half of the world's population are concentrated in the cities.However, distribution of urban population in the world is not evenly.A significant diversity in the urbanization levels can be seen in different regions of the world.About 75% of the inhabitants of the more developed regions lived in urban areas in 2010, whereas this ratio was 45% in the less developed regions.It is expected that urbanization will continue to rise in both more developed and less developed regions by 2050 with about 86% and 69%, respectively.These developments have created new physical, social and economic processes in the cities.For example, uncontrolled urban sprawl has leaded the rising of environmental www.intechopen.comAir Pollution -Monitoring, Modelling and Health 78 problems due to high traffic volume, irregular industry, and low quality housing, etc. Massive urbanization in the cities due to the better job opportunities and challenges in the urban areas began first in Europe and then in other regions of the world, particularly in Asia.At this point, urbanization levels have led to a new classification and a concept-megacitywhich is usually defined as a metropolitan area with a total population in excess of 10 million inhabitants.Megacities are highly diverse in the world, spanning from Paris (France), Los Angeles, New York City (USA) in developed countries to Delhi (India), Dhaka (Bengladesh) and Lagos (Nigeria) in developing countries.In today's developing countries, megacities exhibit the highest levels of pollution and therefore, in the studies of the anthropogenic impact on atmospheric composition, have become of primary importance, particularly those having high traffic volumes, industrial activities and domestic heating emissions. How to referenceIn order to correctly reference this scholarly work, feel free to copy and paste the following: Selahattin Incecik and Ulaş Im (2012).Air Pollution in Mega Cities: A Case Study of Istanbul, Air Pollution -Monitoring, Modelling and Health, Dr. Mukesh Khare (Ed.),