Particulate pollutant data gathered during 1968 and 1969 by the cooperating stations of the National Air Surveillance Networks provide the basis for listing the urban and nonurban concentrations of 12 metallic components of suspended particulate matter. The data are presented as cumulative frequency distributions, including the number of valid samples taken, the minimum value, the maximum value, the arithmetic mean, the geometric mean, and the standard deviation or as a composite concentration value for each site for each of the four quarters of the calendar year; a yearly average is reported whenever valid data for all four quarters are obtained. (Author)