Contained in this catalog is a complete listing of U.S. Environmental Protection Agency reports issued in the AP and APTD series and of selected reports in the EPA-R series. The AP group provides information of general interest in the field of air pollution control and is made available to the public through the Government Printing Office. The APTD series is issued to report technical data of interest to a limited readership and includes reports of work performed under contract to the Environmental Protection Agency. The EPA-R series contains reports issued by the EPA Office of Research and Monitoring and available from the National Technical Information Service together with the APTD series reports. Each entry indicates the series number, title of the publication, date, order number, and price. A subject index concludes the work. (BL)