Deposition velocities and washout ratios on a coastal site (southeastern Spain) calculated from 7Be and 210Pb measurements

The activity concentrations of 7Be and 210Pb were measured in Málaga, Southeastern Spain (36°43′40″N; 4°28′8″W) in aerosols, precipitation and dry fallout continuously and systematically for 8 years. At the same sampling point, aerosols were collected weekly on filters and monthly precipitation sampling was carried out to study deposition. The air concentration of 7Be showed a seasonal increase during the spring and summer months while the air concentration of 210Pb was greater in summer. The concentration data of 7Be and 210Pb together with meteorological variables were used for a comprehensive analysis of variations. The specific activities of 7Be and 210Pb in bulk deposition samples showed a similar seasonal trend variation to that of the aerosols concentrations. Using the concentrations of 7Be and 210Pb in air and their depositional fluxes, the deposition velocities of aerosols and washout ratios were calculated. The mean deposition velocity of 7Be and 210Pb over the 8-year period is 0.4 and 1.5 cm s−1, respectively, and the corresponding washout ratios are 477 and 1908, respectively. The results showed a prevailing influence of amount of rainfall for deposition velocities and other factors such as TSP, the number of rainy days and the number of dry days for washout ratios. A comparison of our measurements and other data obtained at different locations in the world was also made.