Population density, pollution and growth

We analyze a growth model where the damage of pollution depends on population density and the character of pollution. From the steady state rates of change, in the social optimum, of a neoclassical and a semi-endogenous growth model respectively, we conclude that the less responsive the damage of pollution is to population density, the more likely is a development path with positive growth in consumption per capita and declining perceived pollution per capita. Non-awareness of the character of pollution may thus give suboptimal solutions. In particular, the commonly held view that pollution is a pure public bad may lead to growth-rate targets that are lower than optimal. Finally, we find that the character of pollution does not influence the transitional dynamics qualitatively.