An appreciable amount of knowledge exists about the effects of community air pollution upon human health. This knowledge comes in part from direct studies of the air pollution health problem and in part from investigations done for other purposes. It is equally apparent that there are many aspects of the subject of the health effects of air pollution on which sound information is lacking. Many years undoubtedly will pass before we have the answers to all the questions involved. Man-made air pollution could be entirely eliminated, but the price that civilization would be required to pay for this would be exorbitant by any standards, whether monetary or otherwise. It is unreasonable to contemplate that we could put a stop to all combustion, the chief source of man-made air pollution. It is logical, however, to consider that the clarification of the air on a qualitatively and quantitatively selective basis is feasible, and in some cases, highly desirable. This can be done, for example, by selectively arresting the contaminants at their source. 404 references.