ABSTRACT
The Clean Air Act of 1970 establishes primary and secondary standards for criteria pollutants. Primary standards protect human health, while secondary standards protect materials, crops, climate, visibility, and personal comfort. Removing some pollutants involves simply substituting materials which perform equally well in the process but which discharge less harmful products to the environment. This method of air pollution reduction usually produces satisfactory control at a low cost. Typical examples are the substitution of high-sulfur coal with low-sulfur coal in power plants. This substitution requires little technological change but results in a substantial pollution reduction. Chemical and petroleum industries have changed dramatically by implementing automated operations, computerized process control, and completely enclosed systems that minimize the release of materials to the outside environment. Some economists view absolute injunctions and rigid limits as counterproductive. They prefer to rely on market mechanisms to balance costs and effects and to reduce pollution. Demand modification and lifestyle changes are another way to reduce pollution.
