ATMOSPHERIC AEROSOL IN AN URBAN AREA - MEASUREMENTS OF TSP AND PM10 STANDARDS AND PULMONARY DEPOSITION ASSESSMENTS

In March 1995 a measurement campaign of atmospheric aerosol in the urb an area of Bologna was carried out by the Institute for Radioprotectio n in the Environment Department of ENEA. Two standards, total suspende d particles (TSP) and a particle fraction with a diameter smaller than 10 mu m (PM10 fraction), were measured with a Total Filter of cellulo se triacetate and with a PM10 Dichotomous Sampler, respectively. A cas cade impactor was also used. Its sampling inlet and its first-stage pl ate showed the same aerodynamic cutoff as the PM10 sampler: this enabl ed a mass granulometric distribution of PM10 fraction to be obtained. Using aerosol size distribution data from the cascade impactor, the de posited mass on the respiratory tract was evaluated for a standard exp osure by means of the deposition model proposed by the International C ommission on Radiological Protection in the general model of the human respiratory tract for radiological protection. TSP and PM10 time-seri es analysis reveals that, on average, TSP concentration data are 20% h igher than PM10 data. The pulmonary deposition assessments show that t he fraction of accumulation mode mass deposited in the alveolar-inters titial region is less than the fraction of Aitken mode mass, but the v alues of the deposited mass are greater because of the higher concentr ation of the accumulation mode obtained during the measurement campaig n. (C) 1997. Published by Elsevier Science Ltd.