tailieunhanh - Urbanization and Urban Air Pollution

Smaller particulates related to combustion are much more dangerous because they are inhaled deeply into the lungs (Cifuentes et al. 2000, Laden et al. 2000). But note that even if particulate matter from soil is excluded, industry is still a relatively minor source of PM emissions, accounting for just 14% of remaining emissions. Even within the industry subsector, maquiladoras are not the leading source of two of the SNIFF air pollutants—PM and SO2. That distinction belongs to small-scale brick kilns (Table 2).2 (Note that, although the SNIFF does not include information on whether the emissions sources in. | Urbanization and Urban Air Pollution Urbanization is a process of relative growth in a country s urban population accompanied by an even faster increase in the economic political and cultural importance of cities relative to rural areas. There is a worldwide trend toward urbanization. In most countries it is a natural consequence and stimulus of economic development based on industrialization and postindustrialization see Chapter 9 . Thus the level of urbanization as measured by the share of a country s urban population in its total population is highest in the most developed high-income countries and lowest in the least developed low-income countries see Data Table 2 . At the same time urbanization is progressing much faster in developing countries than in developed countries Figure . In 1990-95 the average annual growth of the urban population in low-income countries was percent and in middle-income countries percent compared with percent in high-income countries. Because the developing world has a larger population percentages of its population also represent more people. As a result by 1995 almost three-quarters of the world s billion urban residents lived in developing countries. The share of the urban population in the total population of low- and middle-income countries increased from less than 22 percent in 1960 to 39 percent in 1995 and is expected to exceed 50 percent by 2015. Can urbanization serve as an indicator of development A rough indication of the urban contribution to GDP is the combined share of GDP produced in the industry and ser- Figure Urban population 1980 and 1995 55 BEYOND ECONOMIC GROWTH Why is urban air pollution often higher in developing countries vice sectors relative to agriculture. Judging by this indicator cities in developing countries are already more economically important than rural primarily agricultural areas because more than half of the developing world s GDP originates in cities. This is not yet