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CH. 14CH. 14Economics of Pollution Control: An

OverviewEconomics of Pollution Control: An

Overview

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✦ Recall: the flow of mass and energy to the economic system, and the flow of waste products back to the environment.

✦ Need to achieve a balanced set of mass and energy flows

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✦ The amount of waste products emitted determines the load upon the environment.

✦ The damage done by this load depends on the capacity of the environment to assimilate the waste products

✦ We call this ability of the environment to absorb pollutants its absorptive capacity.

✦ If the emissions load exceeds the absorptive capacity, then the pollutant accumulates in the environment.

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Pollution Pollution DamageDamage

Pollutant Pollutant AccumulatiAccumulati

onon

Emission Emission LoadLoad

Absorptive Absorptive Capacity of Capacity of

EnvironmentEnvironment

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✦ Pollutants for which the environment has little or no absorptive capacity are called stock pollutants.

✦ Stock pollutants accumulate over time as emissions enter the environment. Examples of stock pollutants include non-biodegradable bottles tossed by the roadside; heavy metals, that accumulate in the soils near the emissions source

stock pollutants.

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fund pollutants✦ Pollutants for which the environment

has some absorptive capacity are called fund pollutants.

✦ For these pollutants, as long as the emissions rate does not exceed the absorptive capacity of the environment, the pollutants do not accumulate.

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✦ Examples: Many organic pollutants injected into an oxygen-rich stream will be transformed by the resident bacteria into less harmful inorganic matter.

✦ Carbon dioxide is absorbed by plant life and the oceans.

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✦ when fund pollutants are injected into the air or water, they may be transformed into substances that are not considered harmful to people or to the ecological system, or they may be so diluted or dispersed that the resulting concentrations are not harmful.

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✦ The damage caused by local pollutants is experienced near the source of emission, while the damage from regional pollutants is experienced at greater distances from the source of emission.

✦ The limiting case is a global pollutant, where the damage affects the entire planet.

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Defining the Efficient Allocation of Pollution

✦ Residuals must eventually be recycled or returned to the environment in one form or another.

✦ An efficient allocation of resources must take this cost into account. What is meant by the efficient allocation of pollution depends on the nature of the pollutant.

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Stock Pollutants

✦ The efficient allocation of a stock pollutant must take into account the fact that the pollutant accumulates in the environment over time and that the damage caused by its presence increases and persists as the pollutant accumulates.

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✦ By their very nature, stock pollutants create an interdependency between the present and the future, since the damage imposed in the future depends on current actions.

✦ The damage: human health, trees, fish, can be harmed as well.

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✦ Example: consider the allocation of a commodity X.

✦ Suppose further that the production of X involves the generation of a proportional amount of a stock pollutant.

✦ The amount of this pollution can be reduced, but that takes resources away from the production of X.

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✦ The damage caused by the presence of this pollutant in the environment is further assumed to be proportional to the size of the accumulated stock.

✦ As long as the stock of pollutants remains in the environment, the damage persists.

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✦ Efficient allocation: the one that maximizes the PV of the net benefit. In this case the net benefit at any point in time, t, is equal to the benefit received from the consumption of X minus the cost of the damage caused by the presence of the stock pollutant in the environment.

✦ NBt=UXt-Ct

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✦ This damage is a cost that society must bear (same as cost of extracting minerals or fuels).

✦ While for minerals the extraction cost rises with the cumulative amount of the depletable resource extracted, the damage cost associated with a stock pollutant rises with the cumulative amount deposited in the environment.

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✦ They (X and depleted res) both rise over time with the cumulative amount produced.

✦ The one major difference is that the extraction cost is borne only at the time of extraction, while damage persists as long as the stock pollutant remains in the environment.

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✦ Technological progress could modify this efficient allocation.

✦ It could reduce the amount of pollutant generated per unit of X produced; it could create ways to recycle the stock pollutant rather than injecting it into the environment; or it could develop ways of rendering the pollutant less harmful.

✦ Therefore, more of X could be produced with technological progress than without it.

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✦ Note close relation between Stock pollutants and depletable resources.

✦ With depletable resources, it is possible for current generations to create a burden for future generations by using up resources, thereby diminishing the remaining endowment.

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✦ Stock pollutants can create a burden for future generations by passing on damages that persist well after the benefits received from incurring the damages have been forgotten.

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Fund Pollutants

✦ When emission of fund pollutants exceeds the capacity of the environment, they accumulate (some result of stock pollutants)

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✦ Generally, the marginal damage caused by a unit of pollution increases with the amount emitted. However, when large amounts are emitted, the marginal unit can cause significantly more damage.

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✦ Marginal control costs increase with the amount controlled.

✦ Suppose a source of pollution tries to cut down on its particulate emissions by purchasing a device that captures 80% of the particulates as they flow. If the source wants further control, it can purchase another device where it captures 80% of the remaining 20% (or 16% of the uncontrolled emissions)

✦ Thus, the 1st device: 80% reduction from uncontrolled emissions, while the 2nd device (which costs the same as the 1st) would achieve only a further 16% reduction.

✦ Obviously each unit of emissions reduction costs more for the second than for the first.

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✦ Use these two pieces of information on the shapes of the relevant curves to derive the efficient allocation.

✦ A movement from right to left refers to greater control and less pollution emitted. The efficient allocation is represented by Q*, the point at which the damage caused by the marginal unit of pollution is exactly equal to the marginal cost of avoiding it.

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✦ The diagram suggests that under the conditions presented, the optimal level of pollution is not zero.

✦ Remember that we confront this principle every day. Take the damage caused by automobile accidents, for example. Obviously, a considerable amount of damage is caused by automobile accidents, yet we do not reduce that damage to zero because the cost of doing so would be too high.

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✦ The second point is that in some circumstances the optimal level of pollution may be zero, or close to it.

✦ This situation occurs when the damage caused by even the first unit of pollution is so severe that it is higher than the marginal cost of controlling it.