When air pollutant generation is assumed to be proportional to population density a nearly uniform urban population distribution minimizes pollution damage. Subjects discussed are: Population distribution which minimizes damages from area sources with emissions proportional to population density; population distribution which minimizes damages from area sources with emissions a linear transformation of population density; population distribution that equalizes per capita air pollution damages; and the effect of air pollution costs an optimal urban form. Appendices are included on air pollution generation from area sources, air pollution diffusion models, air pollution damage evaluation, urban population distribution explained by density cost functions and population distributions calculations that minimize a quadratic cost function.