Caracterización de aerosoles radiactivos en la ciudad de Barcelona

Resumen

This research work has been developed in order to contribute to the knowledge of radioactive aerosol characteristics and their behaviour in the atmosphere. The study was carried out in the city of Barcelona. The Instituto de Técnicas Energéticas (INTE) of the Universidad Politécnica de Cataluña (UPC) has a wide variety of devices for measuring radioactive aerosols. Therefore, a bibliographical study of natural and artificial atmospheric aerosols was developed. New devices were acquired during the couse of this work: a device for the measurement of the dimensional spectrum of radioactive aerosol particles and another for the measurement of dry and wet deposition. The radionuclides analyzed in this work are the following: Rn-222 progeny, Be-7, K-40, Pb-210 and Cs-137. The information obtained by means of these devices has enabled us to develop a statistical analysis, that might be used to take decisions within the framework of environmental radiological surveillance. Correlations between the radioactive aerosols and meteorological parameters were also studied in order to draw conclusions about radioactive aerosol behaviour. These correlations might be useful for developing studies at other locations. The study of the activity median aerodynamic diameter of the radioactive aerosol particles allowed us to estimate the mean residence time and origin of the aerosol particles. The measurements developed with the dry and wet deposition devices provided us with information on the deposition velocities of some radioactive aerosols for the first time in the city of Barcelona. Cs-137 detection was classified according to the possible origin of different air masses reaching Barcelona. Therefore, with such information it was possible to analyze the probability of measuring re-suspended Cs-137 transported by air masses from different regions. Finally, the appendices include the resolution of basic general equations that enable us to calculate the concentrations of radioactive aerosol concentrations in the air for the measurement devices that are available at the INTE.