Final answer:
The consulting firm determined the efficient level of pollution abatement using the social demand function QS = 100 - 0.000132P, concluding that QS = 67.4 represents the level of reduction where demand is optimized over 25 years at a 7% discount rate.
Step-by-step explanation:
The question assesses the efficiency level of pollution abatement for the Cherry Islands, which are experiencing health effects from airborne pollution. The Cherry islands have a population of 10,000 with two main populations of highland inhabitants and lowland inhabitants. The consulting firm determined that the social demand for semi-permanent reductions in annual emissions (over 25 years with a 7% discount rate) is represented by the demand function QS = 100 - 0.000132P. The accounting firm concluded that the efficient level of abatement is when QS is equal to 67.4. This conclusion likely comes from setting the social demand function equal to the amount of pollution that needs to be abated to achieve an efficient level of environmental quality, given the cost value P that society is willing to pay. Using this method, if we substitute QS = 67.4 into the equation, we get: 67.4 = 100 - 0.000132P, solving for P gives us the cost at which the social demand for abatement is optimized. The process demonstrates how economic principles such as demand functions and efficiency can be used to make environmental policy decisions.