SIZE SPECTRA FOR TRACE-ELEMENTS IN URBAN AEROSOL-PARTICLES BY INSTRUMENTAL NEUTRON-ACTIVATION ANALYSIS

Size-fractionated aerosol samples collected with micro-orifice impactors at Camden, NJ, a heavily industrialized urban area, and at two sites near Washington, DC, were analyzed for elemental constituents determined instrumentally from short-lived neutron activation products. A least-squares peak-fitting method was used with impactor calibration data to determine log-normal distribution parameters, i.e., mass median aerodynamic diameter (MMAD) and geometric standard deviation (sigma(g)) for particles bearing S, V, Br, and I. For these elements, MMADs ranged from 0.24 to 0.65 mum; 0.23 to 0.53 mum; 0.22 to 0.61 mum, and 0.20 to 0.48 mum, respectively.