title: Seasonal variation of 210Pb activity concentration in outdoor air of Milan (Italy).
abstract: Weekly measurements of 210Pb activity concentration on aerosol particles were performed at ground level in outdoor air in Milan (Italy) during the years 2000-2001. The experimental method was based on the delayed alpha spectrometry of in-grown 210Po activity detected on airborne particles collected on a filter support. On the same filter the 214Pb activity concentration was also measured during the sampling. 210Pb weekly concentration values showed a great variability and the average monthly values exhibited a seasonal pattern characterised by maxima in winter and minima in spring-summer. The same seasonal trend was also observed in 214Pb concentration values. 210Pb average yearly values were 0.70 and 0.82 mBq/m3 in 2000 and 2001, respectively, in good agreement with literature data registered at continental sites of similar latitude and longitude. The activity ratio 210Pb/214Pb was used to evaluate the residence time of fine aerosols in the urban air of Milan, which was 1-2 days.
authors.affiliation: Istituto di Fisica Generale Applicata, University of Milan, Via Celoria 16, 20133 Milan, Italy. roberta.vecchi@unimi.it
authors.forename: R
authors.initials: R
authors.lastname: Vecchi
authors.forename: G
authors.initials: G
authors.lastname: Marcazzan
authors.forename: G
authors.initials: G
authors.lastname: Valli
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D004784:Environmental Monitoring; D007558:Italy; D007856:Lead Radioisotopes / Q000032:analysis*; D011059:Polonium / Q000032:analysis*; D011886:Radon; D012621:Seasons
chemical_list: D000336:Aerosols; D000396:Air Pollutants, Radioactive; D007856:Lead Radioisotopes; D011059:Polonium; D011886:Radon