《经济学专业英语教程(第三版·下)》Unit-4.ppt

Unit 4Text:Environmental Protection（环境保护）1.Key words2.Externality3.Forms of environmental pollution4.Causes for environmental pollution5.Controls of environmental pollution6.Questions1.Key wordsenvironmental pollutionone-way externalityuncompensated damageindustrial establishmentmarginal utilityorganic sewageself-purification.atmospheric pollutionpollution controlnoxious dischargesbody of waterpollution abatementwater purificationwater cleanlinessmarginal benefitmarginal costinternalizing the externalitiesbiochemical oxygen demand2.ExternalityA situation in which action by one consumer or producer confers benefit or inflicts damage on another consumer or producer is said to involve externalities.Environmental pollution typically involves one-way externality,in which the actions of one producer or consumer inflict uncompensated damage on other producers and consumers.3.Forms of environmental pollution3.1 Air pollution3.2 Water pollution3.3 Accumulation of solid wastes3.4 Noise pollution3.1 Air pollutionThis is the discharge of noxious gases and solid particles into the atmosphere,leading to“smog”conditions in many metropolitan areas.3.2 Water pollutionThis type of pollution arises from discharge of organic and inorganic wastes into streams and lakes.3.3 Accumulation of solid wastesThe automobile junkyard is the most conspicuous example.3.4 Noise pollutionThis is a level of background noise that can range from mildly unpleasant to literally deafening.4.Causes for environmental pollutionWith the growth of population and production,clean air and pure water have become scarce goods,particularly in the metropolitan areas where most of the population resides.Natural processes can no longer cope unaided with the flow of waste materials,and the environment can become overloaded to a degree that produces permanent deterioration.Discharge of plant nutrients into a lake can stimulate the growth of weeds and algae to the point where the lake fills up with solid matter.Heavy discharge of organic sewage into a river can reduce the oxygen content of the water to the point where it becomes a dead stream,incapable of supporting fish or other life and incapable of selfpurification.Atmospheric pollution in our larger cities could reach the point at which life in these areas would become impossible.5.Controls of environmental pollution5.1 Damage created by water pollution5.2 Social benefits from pollution reduction5.3 Social costs from pollution reduction5.4 Conclusion5.1 Damage created by water pollutionCommunities located downstream have to spend more on water purification to make the water safe and palatable.Industries located downstream may also have to spend money on raising water quality to the level needed for their operations.Fish life may be damaged.Boating and swimming may be prevented.Debris and odors may reduce the attractiveness of recreational areas.5.2 Social benefits from pollution reductionThe marginal benefit of a 1 percent improvement in cleanliness declines as the cleanliness level rises.Rising cleanliness from 20 to 21 percent will yield more benefit than raising it from 85 to 86 percent.5.3 Social costs from pollution reductionPollution abatement also requires use of economic resources.Either production processes have to be changed,equipment must be installed to reduce waste discharges,or water purification systems must be constructed to clean up after the fact.This takes labor and capital;and this is a social cost,regardless of who pays the money cost.It is reasonable to expect that the cost of an additional unit of cleanliness will rise as more and more cleanliness is produced.5.4 ConclusionThe level of water quality should be raised so long as the marginal benefit from further improvement exceeds the marginal cost of achieving it.The gap between private and social cost is eliminated.This is called“internalizing the externalities.”6.Questions(1)What is pollution?Which form of pollution do you find the most serious around you?(2)Why does such pollution around you occur?(3)An important issue in developing environmental control is how pure we want the air or water to be.Explain how economic analysis can be applied to this issue.(4)You have a friend who argues that pollution is an absolute bad,and that complete air and water cleanliness is an absolute good that should be pursued without compromise.What would you reply?