Read the text again and entitle it. Then divide the text into logical parts, give titles to all of them thus making a plan.

Write out all the sentences, expressing the main idea(s) of each logical part.

Condense the sentences of the text where possible.

5. Write an abstract to the text in your own words using the plan and the sentences you’ve written out and condensed.

Remember:

An abstract is an introduction of a reader into the matter.

An abstract is much shorter than a summary.

Points in an abstract are more generalized than in a summary.

Text

Read the text attentively. Try to understand all details. Use a dictionary if necessary.

SULPHUR DIOXIDE

Where does sulphur dioxide come from? Almost all the sulphur dioxide in the air comes from industrial sources. Industrial smelters, which obtain metals from sulphide ores, produce tones of sulphur dioxide daily. Half of the output of sulphur dioxide comes from the burning of coal. All coal contains between 0.5 and 5 per cent sulphur.

sulphur in coal + oxygen in air = sulphur dioxide

The sulphur dioxide escapes up chimneys into the atmosphere.

Worldwide, 150 million tones a year are emitted. The emission is growing as countries become more industrialized. Most of the coal is burned in power stations. These are always situated in the densely populated regions where the demand for electricity is high and where there are plenty of people to breathe in the sulphur dioxide.

What harm does sulphur dioxide do? Sulphur dioxide is a colourless gas with a very penetrating and irritating smell. It is poisonous; at a level of 0.5%, it will kill. The immediate effects of inhaling sulphur dioxide are coughing, chest pains and shortness of breath. Sulphur dioxide is thought to contribute to bronchitis and lung diseases.

What can be done about it?

· Tall chimneys carry sulphur dioxide away from factories. Unfortunately it comes down to earth again as acid rain.

· A number of processes for removing sulphur dioxide from the emission of power plants are being tried (see below).

SUMMARY NOTE

Factories and power stations burn coal, which contains sulphur. They send sulphur dioxide into the air. Metal smelters oxidize sulphides to sulphur dioxide. Sulphur dioxide causes bronchitis and lung diseases. In the upper atmosphere, it reacts with water to form acid rain.

Make a plan of the text. Discuss the text according to the plan.

Retell the text in short according to your own plan.

Discussion.

- How would you rate the quality of the air you breathe: good, fair, or poor?

- What are the major sources of air pollution in your area?

- What is the quality of indoor air where you live and study?

Text

Read the text attentively. Try to understand all details. Use a dictionary if necessary.

ACID RAIN

It was over 150 years ago when an Englishman, Robert Smith, first used the term “acid rain”. In 1858 he wrote: “It has often been observed that the stones and bricks of buildings, especially under projecting parts, crumble more readily in large towns, where much coal is burnt, than elsewhere… I was led to attribute this effect to the slow but constant action of acid rain.” But it was not until the late 1960s that people in different parts of Europe noticed that life was disappearing from lakes and that trees in forests were dying. There were already rain gauges monitoring chemicals in rain when, in 1968, Professor Svante Oden, a Swedish scientist, showed that pollution from industrial areas of Europe could travel over hundreds of kilometers. The link had been made between pollution from industry and the dying fish and trees.

The true effects of acid rain have really become noticeable in only the last 20 years. At first the suggestion that acid rain could be poisoning lakes in Sweden was met with disbelief. But acid rain is a creeping pollution. Its effects have been building up over many decades.

What causes acid rain?

Tall chimneys carry away the sulphur dioxide and other pollutant gases. They are not allowed to pollute the air breathed by the factory workforce or the local residents.

Unfortunately, the acid gases do not disappear. In the air, sulphur dioxide meets water vapour, and reacts to form sulphurous acid. This is slowly oxidized by oxygen in the air to sulphuric acid. When it rains or snows, down comes the sulphuric acid as acid rain or acid snow. Oxides of nitrogen are converted into nitric acid.

Rain is naturally weakly acidic. Carbon dioxide from the air dissolves in it to form the weak acid, carbonic acid. However, sulphuric acid is a thousand times stronger than carbonic acid.

SUMMARY NOTE

Sulphur dioxide and oxides of nitrogen are present in the exhaust gases of coal- and oil-fired power stations. In the atmosphere, these gases react with water vapour to form acid rain.

What harm does acid rain do? The main damage so far has been to lakes and fish, to trees and to building materials such as stone, concrete, metal and cement.

Fish cannot survive in acidic lake water. Thousands of lakes in Canada, Norway and Sweden are now empty of fish. These countries produce very little of the acid rain and snow that falls on them. The pollution is carried to Scandinavia by the prevailing winds from the UK and from Germany, France and other highly industrialized European countries. Canada receives much of its pollution from the USA.

Some countries suffer more than others from attack by acid rain. If the soil contains basic substances, these will partially neutralize the rain as it trickles through the soil. Cold countries like Sweden receive acid snow for many months. During the spring thaw, a huge volume of acidic water is released into the lakes. The soil has no chance to neutralize it. The acidic lake water destroys water plants. As a result, light can penetrate further through the water. Acid lakes look beautifully clear and blue.

The effect of acid rain on trees is considerable. It dissolves minerals from the soil, removing the ions of calcium, potassium, aluminium and lead. Some of these ions are nutrients, which should be absorbed by the roots of the trees. Acid rain deprives the trees of these nutrients.

Building materials suffer from attack byacid rain. Concrete and stone react with acids, forming calcium carbonate. Metals are attacked by acids. Iron railings, steel window-frames, motor vehicles and bridges are all corroded faster when rain water is acidic.

SUMMARY NOTE

Acid rain makes lakes too acidic for fish to live in. It removes minerals from the soil. Trees are deprived of essential minerals and die. Acid rain attacks construction materials such as limestone, cement, concrete and metals.

What can be done about it?

All this damage costs money. Replacing rusty motor vehicles and restoring stonework costs money. The Canadian timber industry is suffering as the growth of trees is affected. Tourism is suffering in Canada and Sweden: tourists do not want to fish in “dead” lakes. Sweden has adopted the practice of spraying calcium oxide into acid lakes. Being a base, calcium oxide neutralizes acids.

American companies have started neutralizing sulphur dioxide at its source. They use jets of wet lime (calcium oxide) to bombard the combustion gases before they leave the chimney. This process removes sulphur dioxide, nitrogen dioxide and other acid gases from the exhaust gases. Cleaning the exhaust gases in this way costs money. The product is calcium sulphate. Some of this by-product can be used as hardcore in road-making. The rest must be removed and dumped.

Another method of removing sulphur dioxide is to “scrub” the exhaust gases with ammonia. The end product of this process is ammonium sulphate. It can be sold in large quantities as a fertilizer.

In 1979, 31 European countries signed the Convention on Long Range Transboundary Air Pollution. In this agreement, each nation agreed to reduce the amount of pollution that it allows to sweep across its frontiers. Canada and the USA have signed a similar agreement.

SUMMARY NOTE

The damage caused by acid is costly. European countries have agreed to stop exporting their pollutions. Industries and power stations are trying methods of reducing their emission of acidic gases.

2. Make sure if you remember the meaning of the following words. Consult a dictionary if necessary:

To observe, to crumble, readily, elsewhere, to attribute, gauge, link, chimney, to prevail, to trickle, jet, hardcore, to scrub, to sweep.

3. Answer the questions:

1. What did Robert Smith write about the phenomenon he called “acid rain”?

2.What causes acid rain?

3. What are the consequences of acid rain?

4. What can be done to reduce the effects of acid rain?

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