GENERATION, CHARACTERIZATION AND INHALATION DEPOSITION OF ULTRAFINE AGGREGATE AEROSOLS

Abstract Ultrafine irregularly-shaped aggregate aerosols of insoluble 67 Ga 2 O 3 were generated by heat treatment of vaporized 67 Ga-tetramethylheptanedione. Size characteristics of these aerosols were determined using an electrical aerosol analyser, a diffusion battery and a transmission electron microscope. By varying the experimental conditions, aerosols were produced with volume equivalent diameters ranging from 0.01 to 0.2 μm. The primary particle sizes were between 0.002 to 0.02 μm and the number of primary particles per aggregate ranged from 10-400. Stereoscopic examination revealed that these particles were three dimensional branched chain-like structures. Deposition and retention of inhaled 67 Ga 2 O 3 aerosols, with volume equivalent dia. of 0.10 and 0.02 μm, were measured in Beagle dogs. The total deposition was 39 ± 19% and 53 ± 24% of the inhaled 0.10 and 0.02 μm aerosols respectively, while alveolar deposition was 25 and 32% respectively. The pulmonary deposition data agree very well with recent inhalation deposition models.