Iowa's air monitoring data from 1959 to 1976 has been compiled in this report for seven pollutants monitored in the State: suspended particulates, sulfur dioxide, nitrogen dioxide, carbon monoxide, hydrocarbons, photochemical oxidants, and sulfates. The data are presented in tabular form for each of the twelve Air Quality Control Regions in the State. To help the reader better understand the large amount of technical information in this report, additional sections discussing the pollutants and pollutant sources, the air monitoring network, and the analysis of data and trends have been added. Brief summary of another Departmental project, the development of a Pollutant Standards Index, is also included.