Federal land managers are responsible for protecting air quality-related values (AQRVs) in parks and wilderness areas from air pollution damage or impairment. Few, if any, class 1 areas are unaffected by regional and global pollutants, such as visibility-reducing particles, ozone and deposition of sulfur (S), nitrogen (N) and toxics. This paper lays out the basic definitions and research findings that managers need to protect natural resources and scenic vistas. A detailed case study is presented that traces the development of scientific knowledge of the effects of S and N on wilderness resources. Gaps in our understanding of deposition and its effects, and managers’ need for monitoring, modeling and data synthesis tools are discussed, with recommendations on how to use science and technology to protect AQRVs in wilderness areas and parks.