Temporal variation of ~(212)Pb concentration in outdoor air of Milan and a comparison with ~(214)Bi

摘要

Continuous measurement of hourly concentrations of ~(212)Pb attached to aerosol particles was carried out during the whole year 2000 in the outdoor air of Milan (Italy). An improved experimental method based on on-line alpha spectroscopy during atmospheric particulate matter sampling allowed the contemporary determination of ~(212)Pb and ~(214)Bi through the deconvolution of the alpha energy spectral distribution analysis. The ~(212)Pb hourly concentrations were about 100 times lower than ~(214)Bi but showed a similar characteristic diurnal time trend. However, the influence of meteorological parameters such as rain and wind was more evident in ~(212)Pb than in ~(214)Bi concentrations. The ~(212)Pb average annual concentration was 0.090+-0.060 Bq/m~3 with daily mean concentration varying from 0.013 to 0.333 Bq/m~3.