Lettres d’Alberti

Seasonal variation of 210Pb activity concentration in outdoor air of Milan (Italy)

“…This seasonal pattern can be ascribed to differences in average meteoclimatic and thermodynamic conditions during the two semesters in Milan and in the Po valley, leading to very different dispersion conditions of atmospheric aerosols (in particular, the average mixing layer height is generally much higher during summertime). A similar 210 Pb seasonal pattern is reported ( 210 Pb_database, 1998;D'Alberti, 2004) for Ispra, a village in the Po valley (about 50 km North from Milan). A reverse pattern of 210 Pb activity concentrations, characterised by low values during wintertime and high values during the summer period, is observed at Mt.…”