Analyzing the Reductions in U.S. Air Pollution Emissions: 1970 to 1990

Findings of inverted-U relationships between income and certain pollutants have generated considerable controversy, yet relatively little is known about the factors underlying these relationships. U. S. emissions of several major air pollutants have begun to decline, mirroring trajectories found using data across countries and time. We examine U. S. emissions of six air pollutants between 1970 and 1990, decomposing the changes into scale, composition, energy intensity, energy mix, and other technique effects. Our results provide a case study of the relative importance of these effects for a country on the downward- sloping portions of its emissions-GDP trajectories for the pollutants examined.