Damaged trees lose their needles or leaves, have stunted growth and damaged bark. This makes it easier for fungi and insects to attack the tree, and as a result the tree may die.
Acid rain not only damages soil but can also affect the trees directly. Pollutants can block or damage the little pores on the leaves through which the plant takes in the air it needs to survive.
LAKES AND WATER
Acid rain can damage the water and the wildlife in lakes. A lake that has been affected by acid rain looks clean and crystal clear, but contains no life. Most wild plants and animals that live in clean, unpolluted lakes cannot live in acid waters.
Fish are poisoned by the aluminium which is washed out of the ground into the lakes. Lakes also receive rainfall directly from the sky.
A healthy lake has a pH of around 6.5 and a large number of plants, insects and fish can live there. In addition, there are a number of animals and birds that feed on the plentiful food in a healthy lake.
As the lake becomes more acidic (the pH gets smaller) the fish find it more difficult to reproduce successfully, as the young fish find it difficult to live in the high levels of acidity and die. It is not only the acid in the water that kills them, but also poisonous minerals like aluminium that are washed out of the surrounding ground into the water. The birds that eat the fish also begin to suffer as the harmful minerals build up inside their bodies.
All over the world there are lakes that have suffered from the effects of acid rain. Unfortunately, there is less wildlife in and around these lakes because a lot of it has died.
BUILDINGS
Soft building stones have always been naturally worn away by the effects of rain and wind, but in recent years the amount of damage has increased. This is because of acid rain.
Famous buildings like the Statue of Liberty in New York, the Taj Mahal in India and St. Paul's Cathedral in London have all been damaged by this sort of air pollution. Much of the damage is caused by dry deposition.
Ordinary houses and other structures can also be badly damaged. You may be able to see some of them on your way to school; your school may be damaged if it is old.
When sulphur pollutants fall on to buildings made from limestone and sandstone they react with minerals in the stone to form a powdery substance that can be washed away by rain.
Acid rain can also damage stained glass windows in churches, railway lines and steel bridges. The acid rain slowly eats away at them all. Building materials crumble away, metals are corroded, the colour of paint is spoiled, leather is weakened and crusts form on the surface of glass.
These sorts of things happened more in the 1950s and 60s when there was more sulphur dioxide in the air.
HEALTH
The pollution from cars and factories that causes acid rain can also damage our health. Drinking water is contaminated with chemicals released by acid rain. In some parts of Sweden childrens hair has reportedly turned green from acid water containing high levels of copper. Aluminium and lead in water can be poisonous at high levels.
In Norway and Sweden lots of people get their drinking water from wells. Many of these contain high levels of metals such as aluminium and so peoples health can suffer.
Although acidic lakes can be harmful to wildlife they are quite safe for humans to swim in.
WHAT CAN BE DONE TO REDUCE ACID RAIN?
Steps can be taken to control the problem of acid rain, but lots of money is needed to make them work.
The gases which come from factory chimneys can be sprayed to remove some of the sulphur dioxide in them.
One way of fighting the effects of acid rain is by dropping lime into lakes and onto forests. This reduces acidity and is called 'liming'. Lime is an alkali made by crushing limestone rock.
Liming has to be repeated every 2 to 5 years and it is expensive. Liming will not solve the problem of acid rain, to do that we must cut down on the amount of sulphur dioxide and nitrogen oxides that are produced.
Power stations can be fitted with special equipment which reduces the amount of pollutants given off when fuel is burned. If we used electricity more carefully, we would not have to make so much, so there would be less pollution.
Pollution from cars can be reduced by fitting the exhaust with a special filter called a catalytic converter. Reducing the amount of car journeys made and travelling by bus, train or bike instead can also help to stop air pollution.
Acid rain is caused by burning coal, oil, petrol and gas. It would be better to change to types of energy that do not cause acid rain, like sun, wind and wave power.
