Foreword
The Clean Air Act of 1970 (CAA) set a national goal of reducingemissions from vehicles, factories, and other pollution sources.Over the next two decades, the law brought considerable improvementsin the Nation’s air quality — yet unhealthy pollution levelspersisted in many major cities.In 1990, Congress amended the CAA to require the use of cleaner-burninggasoline in urban areas with the worst levels of smog-formingand toxic air pollutants caused by motor vehicle emissions. Othercities with pollution levels exceeding public health standardscould participate voluntarily. The Environmental Protection Agency(EPA) specified that 2 percent of the new gasoline contain anoxygen additive to increase its combustion efficiency…
