Taxation of externalities: Direct versus Indirect

First, a model with separable utilities in the externalities is presented to analyze the impact of direct and indirect taxes on the correction of externalities that are caused by the consumption of one good. It is shown that the sign of the indirect tax is based not on the complementarity (or lack thereof) between the two taxed goods, but on the link between complementarity of the two goods for each consumer and the size of the marginal impact on his consumption on the externality. Second, a model of externality aggregate is further developed along the previous lines and alternative definitions of complementarity are considered.