Transportation-related air pollution continues to poison the air we breathe. In the nation's urban areas almost all of the carbon monoxide, about half of the hydrocarbons, and somewhat less than half of the nitrogen oxides (the latter two helping to form photochemical oxidants or smog) come from mobile sources. Inspection/maintenance complements the national effort to control motor vehicle emissions. The Clean Air Act Amendments of 1977 set forth specific requirements for the implementation of motor vehicle inspection/maintenance (I/M) programs. This report contains a policy paper indicating what the Environmental Protection Agency will consider a minimally acceptable program wherever I/M is required by the Act. Also included are sections detailing the benefits, costs, legislation, training and implementation of I/M programs.

Issued Sept. 1978.