Examining the impact of demographic factors on air pollution

This study adds to the emerging literature examining empirically the link between population size, other demographic factors and pollution. We contribute by using more robust estimation techniques and examine two air pollutants. By considering sulfur dioxide, we become the first study to explicitly examine the impact of demographic factors on a pollutant other than carbon dioxide at the cross-national level. We also take into account the urbanization rate and the average household size neglected by many prior cross-national econometric studies. For carbon dioxide emissions we find evidence that population increases are matched by proportional increases in emissions while a higher urbanization rate and lower average household size increase emissions. The results suggest particular concern for developing countries with their high population growth rates and a trend towards urbanization and smaller household sizes. We find a U-shaped relationship between population size and sulfur dioxide emissions. Beyond a threshold level at a small population size, the estimated elasticity increases with higher existing population levels. For sulfur dioxide, other demographic factors do not matter.