环境英语证书考试（PEC）-环境经济学术语Abatement :Reduction in Emissions.Ability-to-Pay Principle :A principle of taxation in which taxes are based on the income or resource-ownership ability of people to pay the tax. The income tax is one of the most common taxes that seeks to abide by the ability-to-pay principle. In theory, the income tax system is set up such that people with greater incomes pay more taxes. Proportional and progressive taxes follow this ability-to-pay principle, while regressive taxes, such as sales taxes and Social Security taxes, dont.The logic behind the ability-to-pay principle is that taxes are collected by the government to finance public goods that provide benefits to all members of society. And because taxes are a diversion of resources from the household to the government sector, it makes sense to tax, or divert income away from, the people who actually have the income.Absolute Advantage :The ability of a producer to produce a higher absolute quantity of a good with the productive resource available.Abundance :A term that applies when individuals can obtain all the goods they want without cost. If a good is abundant, it is free.Accelerator :The causal relationship between changes in consumption and changes in investment.Acid Rain :The precipitation of dilute solutions of strong mineral acids, formed by the mixing in the atmosphere of various industrial pollutants - primarily sulfur dioxide and nitrogen oxides - with naturally occurring oxygen and water vapor.Aquifer :Underground source of waterAcquired Endowments :resources a country builds for itself, like a network of roads or an educated populationAdaptive Expectations :expectations based on the extrapolation of events in the recent past into the futureAdverse Selection :principle that says that those who most want to buy insurance tend to be those most at risk, but charging a high price for insurance (to cover the high risk)will discourage those at less risk from buying insurance at allWhen a negotiation between two people with asymmetric information restricts the quality of the good traded. This typically happens because the person with more information can negotiate a favorable exchange. This is frequently referred to as the market for lemons.For example, lets say youre searching for a car, knowing that some are high-quality and others are low-quality. However, you dont know which category a particular car is in. Suppose theres an equal chance of getting either a high-quality or low-quality car. If youre willing to pay $2,000 for a high quality car, but only $1,000 for the low quality car, how much would you offer for a given car of unknown quality?The expected value of the car is $1,500. In other words, if you bought hundreds of cars, half worth $2,000 and half worth $1,000, the average value of the cars is $1,500 each. Not knowing the quality of a given car, the price you would offer is $1,500- the average or expected price. The chance of overpaying for a low-quality car is offset by the chance of underpaying for a high-quality car.Unlike you, each owner is better aware of the quality of his or her car-they have more information than you. Your $1,500 offer would be accepted by the seller of a low-quality car, but refused by the seller of the high-quality car. Due to the lack of buyers information, high-quality cars would not be sold. The only cars exchanged would be low-quality cars (lemons). Asymmetric information tends to limit quality of products exchanged, adversely selecting the lower quality cars.Aggregate Demand Curve :a curve relating the total demand for the economys goods and services at each price level, given the level of wagesAggregate Expenditures Schedule :a curve that traces out the relationship between expenditures-the sum of consumption, investment, government expenditures, and net exports-and the national income, at a fixed price levelAggregate Supply Curve :a curve relating the total supply of the economys goods and services at each price level, given the level of wages.Allocative Efficiency :Obtaining the most consumer satisfaction from available resources.Ambient Charge :A form of tax on non uniformly mixed pollutants. It is calculated to be the same in terms of the emissions impact on ambient environmental quality at some receptor site. As a result, an ambient charge to a firm closer to the receptor site will normally be higherper litrethan that charged to firms further away.Antitrust Laws :Designed to promote open markets by limiting practices that reduce competition.Assets :any item that is long-lived, purchased for the service it renders over its life and for what one will receive when one sells itWhat a person or business owns.Assistance In Kind :public assistance that provides particular goods and services, like food or medical care, rather than cashAsymme