Environmental levies and distortionary taxation:: Pigou, taxation and pollution

I note an important distinction between the optimal price of environmental quality in a second-best world and the optimal level of environmental quality. Using an analytical general equilibrium model, I show that for reasonable parameter values, an increase in tax distortions (arising from an increase in required tax revenues) leads to a fall in the optimal Pigouvian tax rate even while environmental quality improves. In general, knowledge of the direction of changes in optimal environmental tax rates due to changes in the economy is not sufficient for understanding the impact on environmental quality.