Exploring the Aspects of Acid Rain

Exploring the Aspects of Acid Rain
What is Acid Rain? Acid rain is the term used to describe the deposition of acidic air pollution. Although some air pollutants fall directly back to Earth, a lot of them return in rain, snow, sleet, hail, mist or fog, hence the term ?acid rain?. Unpolluted Rain All rain is slightly acidic as it contains carbon dioxide, a gas found in air. Unpolluted rain usually has a pH of between 5 and 6. Acid rain has been found to have a pH as low as 3 and in some cases even lower. [image] [image]1 2 3 4 5 6 7 8 9 10 11 12 13 14 Acid Neutral Alkali Acid rain What Causes Acid Rain? When power stations, factories, houses and cars emit pollution into the air, it contains chemicals like sulphur dioxide and nitrogen oxides. These chemicals may either fall directly back to the Earth due to gravity, these are called dry deposition, or they may mix with water (moisture) in the air to form acids, this is wet deposition. Once acids have formed, they can be transported long distances by the wind before being deposited in rain, snow or hail.
In Britain, 90% of sulphur dioxide pollution comes from power stations and industry. Once in the air, sulphur dioxide mixes with moisture to form sulphuric acid, which will later fall as acid rain. One of the largest sources of air pollution in Britain is transport. The number of vehicles on Britain?s roads is constantly increasing and pollution from them is now a major problem. Today there are about 23 million vehicles on the road in Britain, 20 million of which are cars. Nitrogen oxides pollution from cars contributes to acid rain. The [image] nitrogen oxides given off by exhaust fumes mix with moisture in the air to form nitric acid. Which Country?s suffer most from Acid Rain? The countries that suffer most from acid rain are those to which the wind carries the acid rain. These are not always the country?s from which the pollutants were emitted. For example Sweden and north West Germany are affected by the emissions from Britain, France and Spain because the prevailing winds carry the rain over to them. The rain is having disastrous effects on these countries. In Germany the rain has destroyed a quarter of the Black Forest. In Sweden 18000 lakes are now dead because the acidity is to high for plants and animals to survive in. How does it affect the Ecosystems and Human Environment? Acid rain can be harmful to the Ecosystems in lots of different ways. It can affect the lakes and the plants and animals that live in them. Although lakes can withstand a certain amount of acid rain, after a while, their acidity will increase. When this happens the water in the lake can turn a clear blue due to a loss of organic matter that is usually dissolved in the water. The range of plants and animals usually decreases. Some of the organisms affected by acidified water include leeches, snails, crayfish, and many species of insect, salmon and trout. Others like rushes, pike and eel are more resistant to acidic water. Other Wildlife is affected by acid rain not just that in the lakes and rivers. This includes wildlife living in soils like earthworms, and those dependent upon them, like birds. The whole of the food chain can be affected. If the worms are poisoned and the birds eat them and are in turn eaten, they are all affected. The same thing can happen to the wildlife that feeds on the inhabitants of the lakes. [image] This is a chart that shows us what acidity the fish can survive in. Trees have also been affected. The wet deposition is leeching vital nutrients away from the soil and replacing them with harmful ones so the trees cannot grow. Acid rain has already destroyed thousands of square meters of forest in Europe and Canada. [image] It is not just the Ecosystems that have been affected by Acid Rain the human environment has been affected as well. It erodes buildings that had previously been able to withstand all kinds of weather. Ancient monuments are affected by acid rain more than modern buildings because they are often made of limestone or marble. [image] The Taj Mahal in India is an example of a building that has suffered deterioration due to acid rain. The acid also gets into our water supply that can become more acidic and this could become a future health risk. What Solutions are there for Acid Rain? SO2 emissions from power stations can be reduced before, during, or after combustion. ? If a fuel with a low sulphur content (such as North Sea gas or oil) is burned, not much sulphur dioxide will be formed. However, low sulphur fuels are more expensive because they are in greater demand, and although high-sulphur fuels can be treated to reduce their sulphur content, this is very expensive. ? The SO2 created during combustion can be absorbed if an appropriate chemical (such as limestone) is present as the fuel burns. ? Once the fuel has been burned, the SO2 can be removed from the exhaust gases. Most systems spray a mixture of limestone and water onto the gases. This mixture reacts with the SO2 to form gypsum, a useful building material. Another option is not to burn fossil fuels but use alternative energy sources. This also has other advantages because the earth?s fossil fuels are running out. But all these alternatives are very expensive and have drawbacks to them. Laws have been passed so that power stations have to cut back on their emissions and scientists are working on alternatives. There are also temporary solutions to the problems like liming lakes but these only treat the symptoms not the illness. My Projections for the Future. I think that people don?t take acid rain seriously enough. I didn?t know how bad it was until I did my research for this project. So I think that people and Governments will just ignore it until it is too late and something drastic happens, like acid rain affecting the Rain Forests.

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