This paper outlines the provisions of the 1970 Clean Air Act and the steps that must be taken by the federal government, state and local governments, industry, and the public to implement its provisions. The basis of the standards to be issued under the Act is the need to protect the public health and welfare. The need to attain them will either force the use of available technology or create new pressures for the discovery and demonstration of new methods to control air pollution. The federal government will set the goals, it will be up to the state and local administration, planners, and technicians to find ways to meet them. The effects of this at all levels of government is outlined.The automobile is the source of about half of the air pollution in the United States. Therefore, the automobile is the principal target of the Clean Air Act. This may well press the internal combustion engine to its design limits and require new approaches by industry and its engineers.