The Optimal Pricing of Pollution When Enforcement is Costly

We consider the pricing of a uniformly mixed pollutant with a model of optimal, possibly firm-specific, emissions taxes and their enforcement under incomplete information about firms’ abatement costs, enforcement costs, and pollution damage. We argue that optimality requires an enforcement strategy that induces full compliance by every firm, except possibly when a regulator can base the probabilities of detecting individual violations on observable correlates of violators’ actual emissions. Moreover, optimality requires discriminatory taxes, except when a regulator is unable to use observable firm-level characteristics to gain some information about the variation in firms’ abatement costs or monitoring costs. In many pollution control settings, especially those that have been subject to various forms of environmental regulation in the past, regulators are not likely to be so ill-informed about individual firms. In these settings, policies that set or generate a uniform pollution price are inefficient.