IS?ROI)UC?•OS our present air pollution control schemes have been based on empirical studies which are open to questions as to Before proceeding to a discussion of recent develop-whether they are optimum or even realistic. The current ments and advances in the research areas of atmospheric costs associated with control of automobile emissions chemistry and air quali.ty it will be useful to describe' alone are estimated by the National Academy of Sciences briefly the subjects with which we are dealing. Atmospheric chemistry is a mixture of traditional subjects from chemistry and from meteorology. Its practitioners range from chemists with an interest in the atmosphere to meteorologists working on atmospheric composition. At the core is a small group trained or experienced in both fields who are often members of both the American Meteorological Society and the American Chemical Society and feel comfortable in both communities. As a subject, atmospheric chemistry has theoreticians, experimentalists, bureaucrats, and politicians like any other branch of science.
Air quality is an administrative and often political issueand is one of the main areas of attention for atmospheric chemists. The maintenance (or attainment) of adequate air quality requires a sound understanding of the chemical reactions, processes, and cycles of the air in urban, regional, and global settings. Most of the past and many of