NUCLEAR ANALYSIS OF TRACE-ELEMENTS IN SIZE-CLASSIFIED SUBMICROMETER AEROSOL-PARTICLES FROM A RURAL AIRSHED

Ambient aerosol particles in the rural Deep Creek Lake area of western Maryland were size classified with a 6-stage horizontally configured micro-orifice impactor and analyzed for up to 45 elements by instrumental neutron activation analysis. A minimum of 26 elements, including Al, As, Br, Ca, Ce, Cl, Co, Cr, Fe, K, La, Mg, Mn, Na, Se, Sb, V, Ti, and Zn, could be detected on at least three of five submicrometer impaction stages in samples collected for 6–24 h, for which total fine-particulate loadings ranged from 180 to 400 μg. These elements include most of those used in receptor models to apportion the contributions of sources and track the movement of air masses. Analytical uncertainties for many of the elements were < 15% in samples with loadings of 240 and 400 μg. Evidence for particle bounce was observed when sample loadings were ≥1 mg. Substrate blank concentrations often precluded analyses for Ag, Cu, Gd, I, In, Nd, Se, Sm, Ta, Th, and Yb on lightly loaded stages. Contamination by Co, Cr, and Zn was evident in at least some of the samples, as was loss of Br during storage and neutron irradiation. © 1990 Elsevier Science Publishing Co., Inc.