Whether urbanization economies are caused by urban diversity or urban scale is not clear in regional and urban economics literature. Many empirical studies have used either city population size or urban industrial diversity to measure urbanization economies and have reached different...

We demonstrate a striking but previously unnoticed relationship between city size and the black-white wage gap, with the gap increasing by 2.5% for every million-person increase in urban population. We then look within cities and document that wages of blacks rise less with agglomeration in the...

We present evidence that benefits from agglomeration concentrate within race. Cross-sectionally, the black-white wage gap increases by 2.5% for every million-person increase in urban population. Within cities, controlling for unobservable productivity through residential-tract-by-demographic...

AbstractWe review recent empirical economic studies on urban ambient air pollution from a mayor’s perspective. We discuss the sources of urban air pollution, the economic costs that it imposes, and the policy tools available to a mayor to alleviate it. For economic costs, we briefly summarize...