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0.1 Introduction
Since the Industrial Revolution the ammount of harmful chemicals put into the atmosphere by man has been increasing steadily.
Acid rain is only one of many pressures on our environment caused by the modern way of life.
The global warmig effect and the deforestation of the tropical areas are also two major problems we must face today.
However, this way of life depends on the resources the enviroment provides to us and if we continue to destroy the environment, then it will not be able to support us any longer.
I will be telling you more about acid rain and how it can damage the environment.
0.2 Air pollution
Most air pollution is a result of burning fossil fuels like coal and oil.
These fuels have been formed over thousands of years from dead plants and animals.
When the fuel is burnt, not only the energy is released, but many other chemicals as well, including sulphur and nitrogen that the organic material contained. These substances are two of the most important ingredients of acid rain.
Another chemical released into the atmosphere in high quantities is carbondioxide. The effect of this chemical is to help the global warming effect.
The pollution we talk about is created mostly by traffic, factories and cities.
0.2.1 What happens to air pollution ?
Some of the pollution falls to the ground very quickly, before it is absorbed by moisture. It settles on trees, buildings and lakes, usually in and around the area where it was produced.
This is called 'dry deposition'.
When water evaporates from seas, lakes or land, the moisture is neither acid nor alkaline.
It is neutral.
But the moisture can absorb gases, like carbon dioxide, found in the atmosphere, and become a weak acid.
Even worse, the moisture can react with the sulphur or the nitrogen from the air pollution, and thus becoming dilute sulphuric and nitric acids. This is described as acid rain.
Clouds of acid rain can be travelling a long distance before they rain down their enviroment-destroying liquid.
In winter, when acid rain falls as snow, the snow collects on the ground, holding on as acids.
In spring, when the snow melts, there is a sudden surge of water which flows across the land into streams and lakes.
Sometimes the water in these lakes and rivers becomes so polluted from one day to another that ecological disasters, like mass dying of fish, are the result.
0.2.2 How far can pollution be carried ?
The pollution is carried by the wind. It depends on the weather how long it stays in the air before it is deposited on the ground.
If it is cloudy and wet, the pollution reacts with the water in the air and rains down to the earth, but if it is dry, then even a gentle wind of 16 kilometres per hour can carry the pollution over 1,600 kilometres in five days.
The longer the pollution stays in the atmosphere, the more chemical reactions can occour, making the pollution more and more harmful.
0.3 Damage to the soil
All chemicals that are absorbed by the rainclouds are rained back to the earth and there they accumulate in the ground and destroy an important part of the biospere.
It is an alarming development that much of the farmland in industrialized countries is contaminated with harmful chemicals and heavy metals.
0.4 Damage to the trees and forests
The forests and especially the rainforests of South America help to control the global warming effect because plants use vast quantities of carbondioxide to produce oxygen.
In recent years, large areas have been destroyed, as the trees are cut down for wood, burned for farmland or the trees simply died because of extensive pollution.
Fact is that in heavily industrialized areas 40 per cent of the trees are dead or dying from acid rain.
0.5 Damage to buildings
If you look at many buildings, especially old ones, you may well notice that the building materials are breaking up. Building materials weather naturally, but over a long period of time, usually many centuries.
Acid rain speeds up the process.
Good examples in Austria are Saint Stephen's Cathedral, the Votiv Cathedral and the City Hall of Vienna.
Acid pollution can also corrode metals quickly (everyone knows the green covering on copper).
Millions of schillings had to be and have to be spent to restore these famous buildings.
But who should pay ? Should it be the taxpayers of Austria or the factories that caused the pollution in the first place ?
The problem of pollution does not stop at the borders of a country!
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