The last century has witnessed dramatic changes in the world economy. The service (tertiary) sector, which at the beginning of the 20th century was of little importance relative to agriculture and manufacturing, has become the dominant sector today, accounting for 80% and more of value added in...

We study environmental pollution in an economic geography framework with two cities, where pollution arises from commuting within cities, goods transport between cities, production of manufacturing and agricultural goods, and residential energy use. We find that city size has an ambiguous effect...