Search

A series of measurements of particulate samples collected on paper filters in Palermo (Italy) during 1995–2005 has been performed to detect 210 Pb air activity concentration and, along with previous similar data on 7 Be, to evaluate their activity ratio. Average values for the daily activity concentrations of 7 Be and 210 Pb are found to be 4.7 and 0.6 mBq m − 3 , respectively, 9.8 being the average activity ratio. Data confirm a seasonal behavior for both radionuclides. A correlation between 7 Be and 210 Pb air activity concentrations seems to exist, despite their different origins. The time behaviors of both 7 Be and 210 Pb air concentrations and 7 Be/ 210 Pb activity ratio have been compared with some meteorological parameter time series. The analysis of the data shows a weak correlation with rainfall, while no correlation can be established with other parameters. Monthly and weekly average values have been reconstructed taking into account missing data, in order to carry out homogeneous comparisons with available data from other geographical areas. Data series correlations and the frequency analysis show the importance of atmospheric transport processes and the influence of meteorological and climatic parameters (in particular rainfall) in determining the concentrations in air of both radionuclides. [ABSTRACT FROM AUTHOR]

Air activity concentrations of 7Be in Palermo determined for the period January 1995–December 2002 by γ-ray spectrometric analysis of particulate samples collected on paper filter by a high-volume sampler (~900 m3 h−1) are reported. The temporal behaviour of 7Be concentration presents the same characteristics already observed in the measurements carried out over the previous 13-year (1982–1994) investigated period. The mean value of 5.06 mBq m−3 obtained from the analysis of the 4636 particulate samples collected from 1982 to 2002 can be considered a representative value of 7Be air concentration at ground level in our geographical zone. The comparison of long-term variation in the 7Be concentrations with the cyclic solar activity—extended to the whole period of 21 years—confirms the inverse correlation between the two quantities. [Copyright &y& Elsevier]