Variations of 7Be and 210Pb (1992-1999) in air at a sampling station on the mediterranean coast

Abstract

The activity concentrations in air of 7 Be and 210 Pb have been investigated at Málaga (South-East Spain) from 1992 to 1999. In this period, the measurements yielded an average 7 Be activity concentrations at ground level of 4.16 • 10 -3 Bq m -3 and an average of 0.54 •10 -3 Bq m -3 for 210 Pb. The variation of the data with time was studied by time series analysis and seasonal patterns were identified. Activity concentrations of 7 Be and 210 Pb were greatly affected by the meteorological conditions showing pronounced differences between seasons. Maximum activity concentrations in air were systematically observed in spring-summer of each year for 7 Be and in summer for 210 Pb. Minimum activity concentrations were observed in autumn for 7 Be and in autumn-winter for 210 Pb. In the long term, annual variations of approximately a factor of 1.7 were observed in 7 Be activity concentrations and a factor of 1.8 for 210 Pb. The study reveals that much of the variability in the concentration activities is explained by temperature, rainfall, relative humidity and wind speed.