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pollution
Physics
An undesirable change in the physical, chemical, or biological characteristics of the natural environment, brought about by man’s activities. It may be harmful to human or nonhuman life. Pollution may affect the soil, rivers, seas, or the atmosphere. There are two main classes of pollutants: those that are biodegradable (e.g. sewage), i.e. can be rendered harmless by natural processes and need therefore cause no permanent harm if adequately dispersed or treated; and those that are nonbiodegradable (e.g. heavy metals such as lead in industrial effluents and DDT and other chlorinated hydrocarbons used as pesticides), which eventually accumulate in the environment and may be concentrated in food chains. Other forms of pollution in the environment include noise (e.g. from jet aircraft, traffic, and industrial processes) and thermal pollution (e.g. the release of excessive waste heat into lakes or rivers causing harm to wildlife). Recent pollution problems include the disposal of radioactive waste; acid rain; photochemical smog; increasing levels of human waste; high levels of carbon dioxide and other greenhouse gases in the atmosphere (see greenhouse effect); damage to the ozone layer by nitrogen oxides, chlorofluorocarbons (CFCs), and halons; and pollution of inland waters by agricultural fertilizers and sewage effluent, causing eutrophication. Attempts to contain or prevent pollution include strict regulations concerning factory emissions, the use of smokeless fuels, the banning of certain pesticides, the increasing use of lead-free petrol, restrictions on the use of chlorofluorocarbons, and the introduction, of catalytic converters to cut pollutants in vehicle exhausts.
Chemistry
An undesirable change in the physical, chemical, or biological characteristics of the natural environment, brought about by man’s activities. It may be harmful to human or nonhuman life. Pollution may affect the soil, rivers, seas, or the atmosphere. There are two main classes of pollutants: those that are biodegradable (e.g. sewage), i.e. can be rendered harmless by natural processes and need therefore cause no permanent harm if adequately dispersed or treated; and those that are nonbiodegradable (e.g. heavy metals (such as lead) in industrial effluents and DDT and other chlorinated hydrocarbons used as pesticides), which eventually accumulate in the environment and may be concentrated in food chains. Other forms of pollution in the environment include noise (e.g. from jet aircraft, traffic, and industrial processes) and thermal pollution (e.g. the release of excessive waste heat into lakes or rivers causing harm to wildlife). Recent pollution problems include the disposal of radioactive waste; acid rain; photochemical smog; increasing levels of human waste; high levels of carbon dioxide and other greenhouse gases in the atmosphere (see greenhouse effect); damage to the ozone layer by nitrogen oxides, chlorofluorocarbons (CFCs), and halons; and pollution of inland waters by agricultural fertilizers and sewage effluent, causing eutrophication. Attempts to contain or prevent pollution include strict regulations concerning factory emissions, the use of smokeless fuels, the banning of certain pesticides, the increasing use of lead-free petrol, restrictions on the use of chlorofluorocarbons, and the introduction, in some countries, of catalytic converters to cut pollutants in car exhausts.
Chemical Engineering
A substance whose uncontrolled release can cause damage to human and animal life, plants, trees and other vegetation, and the environment in general. Airborne pollutants may be in the form of gases, mists, vapours, clouds, dust, smoke, soot, and fumes. Waterborne pollutants may contaminate land and water courses such as rivers. Non-biodegradable pollutants include heavy metals, certain pesticides, many types of plastics, and chlorinated hydrocarbons. Biodegradable pollutants such as certain plastics and sewage can be broken down by microorganisms over a period of time and rendered harmless. Airborne and waterborne radioactive pollutants have a lasting effect on the environment and can enter the food chain. See air pollution; water pollution.
Biology
An undesirable change in the physical, chemical, or biological characteristics of the natural environment, brought about by human activities. It may be harmful to human or nonhuman life. Pollution may affect the soil, rivers, seas, or the atmosphere (see air pollution). Some pollutants are biodegradable (e.g. sewage), which means that they can be rendered harmless by natural processes and need therefore cause no permanent harm if adequately dispersed or treated; others are nonbiodegradable (e.g. heavy metals in industrial effluents (see heavy-metal pollution) and DDT and other chlorinated hydrocarbons used as pesticides), and these accumulate in the environment and may be concentrated in food chains. Other forms of pollution in the environment include noise (e.g. from jet aircraft, traffic, and industrial processes), thermal pollution (e.g. the release of excessive waste heat into lakes or rivers causing harm to wildlife), and light pollution (from street lights, buildings, etc., which can disorientate wildlife). Current pollution problems include high levels of carbon dioxide and other greenhouse gases in the atmosphere (see greenhouse effect); discarded plastic debris in watercourses and the oceans, harming aquatic and marine life; the disposal of radioactive waste; acid rain; photochemical smog; increasing levels of human waste; and pollution of inland and coastal waters by agricultural fertilizers and sewage effluent, causing eutrophication (see eutrophic). Attempts to contain or prevent pollution include strict regulations concerning factory emissions, the use of smokeless fuels, the banning of certain pesticides, greater use of renewable energy sources, the use of catalytic converters to cut pollutants in car exhausts, and the collection and recycling of plastic waste. See also climate change; sustainable. http://www.worstpolluted.org/ The ten worst-polluted places in the world and the ten most-polluting industries; a report by Pure Earth (formerly the Blacksmith Institute) and Green Cross, Switzerland
Geography
The presence in, or introduction into, the environment of a substance that has harmful or poisonous effects. ‘As far as the geographical distribution of pollution is concerned: pollution is concentrated in agglomerations, as in [major] Third World cities…environmentally harmful activities are located in peripheral regions, as is the case with nuclear power stations in industrialised countries…[and] in some cases…pollution is rather uniformly distributed over the country’ (Rauscher and Bouman siti.feem.it/worldcongress/abs2/rausch2.html). See Lange and Quaas (2007) BEJ Econ. Analys. & Policy 7, 1 on the effect of environmental pollution on agglomerations. Diffuse pollution is pollution from widespread activities with no one discrete source; for example from pesticides or from urban run-off.http://glossary.eea.europa.eu/EEAGlossary/D/diffuse_pollution Definition of diffuse pollution. Biodegradable pollutants like sewage, cause no permanent damage if they are adequately dispersed; see Zagorc-Koncan and Somen (1999) Water Sci. & Tech. 39, 10 on biodegradable industrial pollution. Land cover change and the expansion of modern agricultural practices has significantly increased leaching of chemicals to the surface waters, leading to the degradation of aquatic ecosystems worldwide (Donner (2003) Glob. Ecol. & Biol. 12, 4). Non-biodegradable pollutants such as lead, may be concentrated as they move up the food chain; this is biological magnification—see J. Nathanson (2002). Within western Europe, air pollution, associated with basic industries such as oil refining, chemicals, and iron and steel, as well as with motor transport, is probably the principal offender, followed by water and land pollution. Other forms include noise, and thermal pollution. Present-day problems of pollution include acid rain and the burning of fossil fuels to produce excessive carbon dioxide. The pollution haven (or ecological dumping) hypothesis states that if free trade occurs between countries with different environmental standards, countries with lower standards will develop a comparative advantage in relatively ‘dirty’ industries (Rauscher (1994) Oxf. Econ. Papers 46).
Economics
Damage to the environment by the emission of noxious substances, which may be dirty, toxic, radioactive, or pathogenic. This may affect water, air, or land surfaces, in some cases over wide areas. Pollution resulting from economic activities is a major source of negative externalities. See also permit to pollute.
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