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Acid rain is caused by the release of the sulphur dioxide and nitrous oxides. The main sources of sulphur dioxide are coal-fired power stations and metal working industries. The main sources of nitrous oxides emissions are vehicles and fuel combustion.
Sulphur dioxide reacts with water vapor and sunlight to form sulphuric acid. Likewise nitrous oxides form nitric acid in the air. These reactions take hours, or even days, during which polluted air may move hundreds of kilometers. Thus acid rain can fall far from the source of pollution.
When mist or fog droplets condense they will remove pollutants from the air and can become more strongly acid than acid rain. Even snow can be acid. Gases and particles, not dissolved in water, with a low pH can also be deposited directly onto soil, grass and leaves. It is possible that even more acidity is deposited in this way than by rain! Not much is known about this process, and it is particularly difficult to study.
There are some undoubted effects of acid rains:
Acid rains can increase the acidity of lakes, dams and streams and cause the death of aquatic life.
Acid rain can increase the acidity of soil, water and shallow groundwater.
Acid rain has been linked with the death of trees in Europe and North America. In spite of a great deal of research, no one yet knows exactly how acid rain harms forests. Most of the forests of Europe consist of huge areas of one tree species. This encourages the spread of plant pests and diseases. It seems likely that acid rain weakens the trees, perhaps helped by other pollutants such as ozone, and then leaves the trees open to attack by disease. Acid rain also disrupts the availability of soil nutrients. The final death of a tree may result from a combination of stresses such as heat, cold, drought, nutrient disruption and disease.
Acid rains erode buildings and monuments.
Acid particles in the air are suspected of contributing to respiratory problems of people.
Scientists have many ways to solve this environmental problem. We need to use energy more efficiently at home, in our vehicles and in industry. We will have to think hard about alternative energy sources. It is possible to remove acidic emissions from coal burning, but this is very expensive. It may be possible to breed crops and trees that resist pollution, but this would only be a partial solution. In practice we will probably need a combination of all these ideas and innovations.
Measures of the protection of atmosphere
Measures of the protection of atmosphere are subdivided into three large groups:
First group: decrease measures of gross amount of contamination, thrown out into atmosphere. This is the improvement of the quality of fuel, using of special liquids in fuel etc. Same group of measures includes perfecting of technological processes including development of the closed cycle production without making of harmful substances into atmosphere.
The second group includes measures of protection of atmosphere by dispersion, processing and neutralization of harmful wastes.
The third group of measures assumes prevention of the air contamination by rational placing of the «dirty» enterprises – sources of harmful wastes with consideration of natural conditions and potential possibility of the air contamination.
For realization of atmosphere protection measures the strict state control of air environment, economic and legal stimulation of measures for control of its pollution are also important.
Water pollution
Comprising over 70% of the Earth’s surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognize this fact, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our planet to the point where organisms are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution.
Реферат опубликован: 20/12/2006