How do economic models measure the social cost of pollution?

• A. By subtracting external cost from private costs.
• B. By counting private costs only.
• C. By measuring how pollution reduces consumer utility.
• D. By adding external cost of pollution to private production costs, producing the MSC curve.

Answer: (D)

The social cost of pollution is built by adding the costs that producers pay (private production costs) to the costs borne by others in society (the external costs of pollution). At each level of output, the marginal social cost equals the private marginal cost plus the marginal external cost. This creates a marginal social cost (MSC) curve that lies above the private-cost curve, because pollution imposes additional harm beyond what the producer pays. In other words, MSC = private cost + external cost. This is why economic models measure social cost by summing those two components. Subtracting external costs or counting only private costs ignores part of the total burden, and focusing only on how pollution affects consumer utility misses the full production-related costs borne by society.