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Pollutants are substances which directly or indirectly damage us or the environment. Many of the compounds which are dangerous to the environment can also be harmful to us in the long-term and come from nuclear- fossil sources, like petroleum.
Pollutants can cause the destruction of areas of the environment which are protective to us. CFCs were carefully chosen not to be damaging to humans, however a side effect causes an effect held to be very damaging to the environment. They diffuse in to the upper atmosphere where they stay for some time. When the sun's radiation does break them down, they turn in to highly-reactive radicals. These catalyse the break down of the ozone layer, which protects us from cancer-causing ultraviolet radiation from the sun. CFCs are especially damaging because one CFC molecule can cause the breakdown of many millions of ozone molecules.
Some pollutants imbalance environmental processes by causing an excess of a compound which is already present naturally. Carbon dioxide is already present in the atmosphere - indeed it is vital for life on earth. Carbon-dioxide helps keep the earth warm by trapping infra-red radiation, which would otherwise be reflected in to space. However if there is too much of it present the earth's temperature will rise too high. It is thought that this would cause many destructive effects including the flooding of many low-lying areas, and an imbalance of the earth's weather system. Another example of these compounds are nitrate-containing fertilizerFertilizers are chemicals given to plants with the intention of promoting growth; they are usually applied either via the soil or by foliar spraying. Fertilizers typically provide, in varying proportions, the three major plant nutrients ( nitrogen, phosphs. When these leak in to streams they cause plants and algae to grow too fast. This restricts light for plants on the river-bed and they decay. Microbes feed off the decaying plants and use up all the oxygen in the lake, causing fish and other plants to start dying off.
Many pollutants have a poisonousThis article is about the dangerous substance. For the band see Poison. skull and crossbones symbol traditionally used to label a poisonous substance. In the context of biology, poisons are substances that cause injury, illness, or death to organisms, usu effect on the body. Carbon monoxideCarbon monoxide chemical formula C O, is a colourless, odourless, flammable and highly toxic gas. It is a major product of the incomplete combustion of carbon and carbon-containing compounds. Sources Carbon monoxide has many common sources. The exhaust of is an example of a substance which is damaging to humans. This compound is taken up in the body in preference to oxygenOxygen is the chemical element in the periodic table that has the symbol O and atomic number 8. The element is very common, found not only on Earth but throughout the universe. Molecular oxygen (O, often called free oxygen on Earth is thermodynamically un, causing the body to suffocate.
Some pollutants are not so dangerous by themselves until they combine with other naturally present compounds. The oxides of nitrogenNitrogen is the chemical element in the periodic table that has the symbol N and atomic number 7. A common normally colorless, odorless, tasteless and mostly inert diatomic non-metal gas, nitrogen constitutes 78 percent of Earth's atmosphere and is a cons and sulphurSulfur (or sulphur see spelling) is the chemical element in the periodic table that has the symbol S and atomic number 16. An abundant tasteless odorless multivalent non-metal, sulfur is best known as yellow crystals and occurs in many sulfide and sulfate are released from impurities in fossil fuelFossil fuels are coal and hydrocarbon fuels or hydrocarbon containing fuels such as petroleum (including natural gas). The utilization of fossil fuels has fueled industrial development and largely supplanted water driven mills and wood or peat burning fors when they are burnt. They react with water-vapour in the atmosphere to become acid rainThe principal natural phenomena that contribute acid-producing gases to the atmosphere are emissions from volcanoes and from biological processes that occur on the land, in wetlands, and in the oceans. The effects of acidic deposits have been detected in. Acid rain damages buildings and makes lakes uninhabitable.
Compounds can be bad pollutants not just by how damaging they are but also because of other factors, such as the length of time that they stay dangerous. Uranium is a radioactive element used in nuclear fission power plants. Once it has been used it is often highly radioactive, meaning even small traces are able to cause cancer and damage unborn children. It will stay like this for many millions of years and has to be kept under adequate storage. Because of the difficulties in safely containing this element many people think it is inevitable that radiation will escape and cause damage to the environment.