Exporting Air Pollution? Regulatory Enforcement and Environmental Free Riding in the United States

Political jurisdictions have incentives to promote pollution spillovers to capture the benefits of economic production within their borders while exporting the environmental costs to their neighbors. The authors examine the extent to which U.S. states engage in this type of free-riding behavior. Studying enforcement of the federal Clean Air Act from 1990 through 2000, the authors employ zero-inflated negative binomial regression to predict the number of state-initiated enforcement actions conducted in counties bordering other jurisdictions. They find that states perform fewer enforcement actions in counties adjacent to international borders but no evidence that states conduct less enforcement in counties that border other states.