||A substance, released into an environment, that causes harm either to living organisms or built structures. The substance may be human-made or natural (see hazard, human-made; environmental hazard) and causes harm when the receiving environment cannot easily assimilate the type or quantity of substance released. One aspect of environmental management is establishing criteria for acceptable and unacceptable levels of particular forms of pollution. This means that pollution is now defined in relation to impacts and in relation to an index of acceptable levels: sometimes there appear to be significant discrepancies between these two.
The effects of pollution range from aesthetic nuisance through to economic loss, health damage, death and long-term environmental degradation. The release of pollution may be sudden (as in Bhopal, India, in 1984), or it may involve a slow accumulation of substances, as in the concentration of heavy metals, herbicides and pesticides in food chains (i.e. bioaccumulation). The impacts of pollution may also be gradual or sudden, short-lived or maintained over a long time period. The impact is also spatial; it may be local, widely dispersed, or far from the source of the pollution (see acid rain). Sometimes the earth is polluted, but this is not noticed until humans re-occupy the already polluted site (e.g. Love Canal, USA). Pollution may be described by its medium (e.g. air or water pollution), by its character (e.g. noise pollution and acid rain) or by its source (e.g. industrial pollution).
Pollution may be regarded as an \'accident\', or it may be understood as the deliberate and inevitable consequences of production processes. Sections of the environmental movement have strongly criticized production processes that generate pollution as being undesirable. Their concerns are partly being heeded because increasingly efforts are being made to \'close the circle\' by using former wastes from processes as inputs into new production processes, in what is known as \'industrial ecology\'. This is sometimes identified with \'ecological modernization\', and is regarded as one form of sustainable development. Due to pollution regulations and the need for corporations to maintain a positive public image, there are almost always economic advantages for corporations to adopt this approach. Regulations are being enforced to prevent the deliberate emission of pollution that is considered unacceptable. Sometimes the pollutant must be treated to a set standard before it is emitted but the setting of standards is not uniform throughout the world, partly because the receiving environments are different, and partly because of concern not to deter economic growth.
The history of pollution is very long. Lead pollution in the water supplies is alleged to have been responsible for madness in Ancient Rome. Cities have always had pollution of some form, such as contamination of water supplies, the pollution of air by industrial processes, the pollution that affects specific occupations (e.g. hatters becoming mad due to the mercury they used), or the emissions from transport (including both manure from horses and exhaust fumes from automobiles). However, contemporary concern with pollution increased dramatically after the smog that killed about four thousand people in London in December 1952, and after the publication of Silent spring by Rachel Carson in 1962 (the book was serialized in The New Yorker, and became a major-seller). Kates (1995) situates the London smog in the longer term and observes that the sharp decrease in pollution following the passing of Britain\'s Clean Air Act of 1956 was part of a longer trend to improve air quality, resulting from the displacement of coal as a source of energy. While older pollutant sources were being phased out, Rachel Carson identified further dangers, those caused by the insecticide DDT. Her book was the forerunner for concerns about many other human-produced substances, ranging from pesticides through to the products of the nuclear industry. Continental and global-scale pollutants such as CFC emissions, acid rain and pollutants that contribute to global warming, have caused most concern for governments, the environmental movement and citizens in so-called developed countries. However, in areas said to be in a state of underdevelopment, it is often the results of local forms of pollution, such as the inability to obtain clean drinking water, that are of the greatest immediate concern.
Pollution has been an issue in human geography through the literature on development. It is increasing in importance as an aspect of environmental justice (Bowen et al., 1995; Harvey, 1996; Low and Gleeson, 1997), particularly in the United States where pollution and other differences in environmental quality are seen as intentional acts of discrimination. These acts are often referred to as \'environmental racism\'.Â (PM)
References Bowen, W. et al., 1995: Toward environmental justice: spatial equity in Ohio and Cleveland. Annals of the Association of American Geographers 85 4: 641-63.Â Carson, R. 1962: Silent spring. Boston: Houghton Mifflin Company.Â Harvey, D. 1996: Justice, nature and the geography of difference. Oxford: Blackwell.Â Kates, R. 1995: Labnotes from the Jeremiah Experiment: hope for a sustainable transition (Presidential Address). Annals of the Association of American Geographers 85 4: 623-40.Â Low, N. and Gleeson, B. 1997: Justice in and to the environment: ethical uncertainties and political practices. Environment and Planning A 29: 21-42.
Suggested Reading Newson, M. 1995: The earth as output: pollution. In R. Johnston, P. Taylor and M. Watts, eds, Geographies of global change: remapping the world in the late twentieth century. Oxford and Cambridge, MA: Blackwell, 333-53.Â Pulido, L., et. al. 1996: An archaeology of environmental racism in Los Angeles. Urban Geography 17: 419-39.