Розділ 2 Air and water of condition of urbanization

2.1. Air pollution

Under the term “ecological disaster” we understand that one constant system changes to another unstable system. For example, increase in average temperature on Earth leads to melting of polar ice, which can have an unpredictable consequence; or spread of the ozone hole can bring all sorts of diseases or death to a many life forms. One or all of these disasters would occur as the product of our activity if the countries won’t pay enough attention to greenhouse effect of emission.

Urban air pollution is one of the most important environmental problems. High

concentration of transportation, industry and people turns the city into perfect polluter of the air. According the statistical data, the main sources of air pollution are vehicle exhaust, industrial emissions, and domestic use of wood, coal and refuse for heating and cooking. But in the city the lion share of air pollution belongs to transportation. Vehicles contribute about 14% of total global air pollution but in big cities it can contribute up to 80% of the city’s emission. There are about 600 million units of vehicles in the world, and every type produces about 3-4 kg of carbon dioxide, more than our nature can absorb.

In most European and North American cities, the concentrations of SO2 and

Suspended Particulate Matter (SPM includes dust, fumes, mists and smoke — SO2

and troposphere ozone) have decreased substantially in recent years. However, in the US every second person has a car, about 170 million cars with the population of 280 million people; high concentration of industry and transportation turned the US into one of the biggest air polluters in the world, even though the number is decreasing. The US account for 26% of the total air pollution in the world.

The problem is not only in developed countries. In many developing countries,

rapid urbanization has resulted in increasing air pollution in many cities. WHO air quality guidelines are often not met and, in mega cities such as Beijing, Calcutta, Mexico City and Rio de Janeiro, high levels of Suspended Particulate Matter (SPM) prevail. The result of air and water pollution is chronic and infectious respiratory disease; water borne diseases; increased mortality rates, particularly among children; and premature deaths – the highest rate being among the poor. In Cairo, the leading polluted city, there are about 10.6 million people with respiratory disorder (SEI 1999). Air pollution is not only the cause of lung disease, but also has become the cause of heard attacks, birth defects and cancer.

In developing countries, transportation is not the main source of air pollution.

For example China and India together have about 600 million bicycles and much,

much fewer cars. If in the US every second person has a car, in China only every 79th person has a car, so the sources of pollution are different. People move from rural to urban areas to find better job and a better life, so many cities in China have a housing problem. Because the citycan’t offer decent housing, people live in small self-built shelters andusually heating and cooking is done by burning a very low quality coal, because it is the only cheap source of energy.

Beijing is one of the air polluted cities in the world and because of air pollution they have a desert problem.

All green plants around the city are dead and any efforts to plant new

trees and grass have had a miserable result. The geographical location plays not last role in the determination of air pollution of cities. For example, some cities in South America, which are located in high mountains have natural problem with free flow of air movement that removes polluted air. Besides, the low oxygen concentration in high mountain areas causes the partial burn of the fuel, which simply worsens the situation. For example Mexico city, the second largest city in the world, has a big problem with smog – dry, smoky fogs, which consist of carbon dioxide and nitrogen dioxide. Sometimes the smog stays for few days in the city

without any movement, causing enormous harm to the health of citizens of

Mexico city.

Дата добавления: 2015-10-29