Gasoline whose composition has been changed (from that of gasolines sold in 1990) to (1) include oxygenates, (2) reduce the content of olefins, aromatics, and volatile components, and (3) reduce the content of heavy hydrocarbons to meet performance specifications for ozone-forming tendency and for release of toxic substances (benzene, formaldehyde, acetaldehyde, 1,3-butadiene, and polycyclic organic matter) into the air from both evaporation and tailpipe emissions.