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( Article Type: Explanation )

Pollution comes in many forms and types. In its broadest sense, pollution can be described as the result of the release to air, water or soil from any process or of any substance, which is capable of causing harm to man or other living organisms supported by the environment. Long-lasting pollution can also affect the physical environment by changing its characteristics through speeding up or slowing down natural processes. One other way of describing pollution is that it is waste that has been inadequately managed or controlled and which results in unnecessary damage.

An example of 'air pollution' is acid rain or 'acid deposition', which occurs when polluting sulphur dioxide and nitrogen oxides released into the atmosphere from industries, towns and cities are transported by prevailing winds to form droplets or particles that fall back to earth. The droplets or particles fall in either a wet or dry form. The wet form falls as acidic rain, snow, fog or even cloud vapour and the dry form as acidic particles. Rain is usually slightly acidic (around pH5.0-5.6) because it contains carbonic acid from chemical reactions in the atmosphere.

However, industrial activity can push the acidity up to pH3 (the same pH as vinegar) and even up as high as 2.3 (same pH as lemon juice), which can be up to about 1000 times higher than normal rainfall. Excessive acidic rain can cause substantial damage to plants and soil.

An example of water and land pollution is the toxic solid or liquid waste that is dumped on land, which can filter into the soil, percolate down and contaminate groundwater. Pollution from radioactive waste (e.g. Chernobyl) can pollute vast areas in different ways, making them uninhabitable to man and beast because of the high levels of radiation, which ultimately cause death. As a basic principle, pollution should be minimised as far as possible.