Have air pollutant emissions converged among US regions? Evidence from unit root tests

Previous studies of income distribution have found evidence indicating that incomes across U.S. regions have converged, supporting the prediction of the neoclassical growth model. A potential shortcoming in these studies is that only one measure of well-being is considered-a measure of wealth linked to incomes or production. This paper examines whether income convergence was accompanied by air pollutant emission convergence. Results from unit root tests provide some evidence that indicators of environmental quality have converged across U.S. regions during the 1929-1994 period.