National Air Surveillance Cascade Impactor Network, 11. Size Distribution Measurements of Trace Metal Components Robert E. Lee, Jr.,l Stephen S. Goranson, Richard E. Enrione, and George B. Morgan US.Environmental Protection Agency, National Environmental Research Center, Research Triangle Park, N.C. 2771 1
~~~
w The National Air Surveillance cascade impactor network operated in six U.S. cities during 1970 with 24-hr samples collected biweekly. The size distribution based on the aerodynamic dimension of the particles (as equivalent Stoke's diameters) of total suspended particulate matter was determined gravimetrically. Samples were also chemically extracted and analyzed with a n emission spectrograph to obtain information on the metal concentration in each size fraction. Particle size data on a quarterly and a n annual basis for each city are reported for lead, iron, copper, zinc, manganese, nickel, and vanadium; less complete data on cadmium, tin, barium, samarium, and molybdenum are also given. The relationship of the metal concentration to the particle size of total suspended particulate matter has been determined for these metals. For particles less than or equal to 3 p diam, iron was found in the highest concentration (3-5 followed closely by lead (1-2 However, for suspended particulate matter less than or equal to 0.5 p in diam, lead was highest (2-4%), whereas iron and the other measured components were markedly lower in concentration (
