Title: Air Pollution in Mega Cities: A Case Study of Istanbul
Abstract: A megacity is defined by the United Nations as a metropolitan area with a total population of more than 10 million people.This chapter provides a brief introduction to the air pollution in megacities worldwide.This is an extensive topic and brings together recent comprehensive reviews from particular megacities.We have here highlighted the air quality in megacities that are of particular relevance to health effects.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.The United Nations Environment Programme Urban Environment (UNEP-UE) unit expressed that more than 1 billion people are exposed to outdoor air pollution annually and the urban air pollution is linked to up to 1 million premature deaths and 1 million pre-native deaths each year.Additionally, UNEP presented the cost of urban air pollution with approximately 2% of GDP in developed countries and 5% in developing countries, respectively.In addition, the UNEP/Global Environmental Monitoring System (GEMS) reported that rapid industrialization, burgeoning cities, and greater dependency on fossil fuels have caused increasing production of harmful pollutants, creating significant health problems in most urban cities.The serious air quality problems, specifically inverse health effects, have been experienced in megacities of both developing and developed countries.due to the exposure to high concentrations of particular matter (PM), nitrogen oxides (NO x ), ozone (O 3 ), carbon monoxide (CO), hydrocarbons (HC) and sulfur dioxide (SO 2 ) depending on country's technology level.Especially, exposure to eleveted levels of particular matter and surface ozone causes loss of life-expectancy, acute and chronic respiratory and cardiovascular effects.Furthermore, damage to the ecosystem biodiversity by excess nitrogen nutrient is an important consequence of pollution. How to referenceIn order to correctly reference this scholarly work, feel free to copy and paste the following: