Voluntary pollution abatement and regulation

We consider private provision of an environmental public good and the link between voluntary pollution-abatement markets and the optimal level of mandatory environmental regulation. We show that voluntary abatement markets react to the level of mandatory abatement imposed and that an optimal regulatory policy must account for that reaction. We consider several assumptions about consumer behavior and find that the voluntary markets reaction to regulation depends on the motivating behavior of consumers. Whether the optimal level of mandatory abatement is higher than the level provided by traditional settings depends on the direction and magnitude of the voluntary markets reaction to changes in mandatory abatement.