Poor and rich countries tend to exhibit better environmental quality (at least with respect to some pollutants) than countries with intermediary per capita incomes. That is, the relation between some measures of environmental quality and per capita income tends to be u-shaped. This paper analyzes within a closed economy model what assumptions are needed regarding preferences, technology and the organization of the political system to generate this observed pattern. The analysis is in part based on a median voter model and is also performed in two frameworks with different degrees of intertemporal decision-making.

JEL Classification: 041, Q20, Q30.