The Effect of Urbanization on Air Pollution Damage

The global shift of population from rural to urban areas has dramatically increased the marginal damage of air pollution emissions in urban areas. Despite a steady decline in overall emissions in the United States, this rising marginal damage in urban areas caused total national damage to increase from 1970 to 2000. Total damage only fell after 2000 because of a dramatic decrease in nitrogen oxide and especially sulfur dioxide emissions. The rising marginal damage in urban areas suggests that environmental policy should emphasize reducing urban emissions of particulates, volatile organic compounds, ammonia, and sulfur dioxide.