Clean air policy and oxygenated fuels: do we get what we pay for?

The Clean Air Act Amendments of 1990 set ambient air quality standards for the United States. Areas that violate these standards (usually large urban centers) are required to use cleaner-burning automotive fuels (oxygenated fuels or 'oxyfuels') during the winter months in some cases and year-round (reformulated gasoline) in the worst cases. Oxygenated fuels are the primary alternative fuel in use, however, cleaning-up our aggregate automobile emissions can be done through many different methods. Using a cross-section of data from the California emissions testing program this paper investigates the environmental benefits gained by the use of oxyfuels. It estimates the actual CO and HC emissions abatement due to the use of the oxyfuel. The results suggest the CO emissions reductions are lower than previously thought due to the differential impact of the fuel on different automobile vintages. Cars built since 1988 have no CO emissions benefits as a result of using oxyfuels. Oxyfuels are also found to have no systematic impact on HC emissions. The oxyfuel smog test results are then compared to emissions' improvements resulting from emissions system repairs. Increased maintenance and repairs are found to be a much more cost-effective method for lowering CO and HC emissions than oxyfuels. (C) 2003 Elsevier Science B.V. All rights reserved.