Summary

Pursuant to a congressional request, GAO reviewed the impact of alternative motor vehicle fuels on air quality.

GAO found that: (1) more than 178 million vehicles are major emitters of hydrocarbons, carbon monoxide, and other air pollutants; (2) over 120 million people live in areas that exceed one or more national air quality standards; (3) the Environmental Protection Agency estimates that alternative fuels are capable of reducing ozone-forming hydrocarbons by at least 80 percent; (4) alternative fuels reduce air pollution and are less likely to form ozone than hydrocarbon; and (5) although alternative fuels offer many advantages to improving air quality, uncertainties remain regarding their specific pollution reduction potential.