Lead-210 in the atmospheric air of North and South Estonia: long-term monitoring and back-trajectory calculations

• Published in: Proceedings of the Estonian Academy of Sciences Vol. 65; no. 4; p. 442
• Main Authors: Isakar, Kadri, Kiisk, Madis, Realo, Enn, Suursoo, Siiri
• Format: Journal Article
• Language: English
• Published: Tallinn Teaduste Akadeemia Kirjastus (Estonian Academy Publishers) 01.01.2016
• Subjects: Air masses; Air temperature; Atmospheric boundary layer; Atmospherics; Boundary layers; Computer programs; Correlation; Estonia; Mathematical analysis; Relative humidity; Sampling; Spectrometry
• ISSN: 1736-6046; 1736-7530
• DOI: 10.3176/proc.2016.4.11

As the first study of long-term atmospheric super( 210)Pb in Estonia, the activity concentration and possible origins of the nuclide were monitored at Toravere, South Estonia, and Narva-Joesuu, North-East Estonia, from 2001 to 2008. Activities of super( 210)Pb in weekly collected air filter samples were analysed using HPGe gamma spectrometry. Results show high weekly, seasonal, and yearly variability in the range from 0.12 mBq m super( -3) to 2.76 mBq m super( -3) (median 0.45 mBq m super( -3)) for Toravere and from 0.08 mBq m super( -3) to 2.53 mB m super( -3) (median 0.43 mBq m super( -3)) for Narva-Joesuu. No significant correlation between the super( 210)Pb activity concentration and meteorological data was found as far as total weekly precipitation, relative humidity, or air temperature were considered. A strong correlation between the super( 210)Pb concentrations from the two sampling sites was present. Back-trajectory calculations made with the METEX software showed clearly that high super( 210)Pb values in surface air were prevailingly caused by continental air masses from the Eurasian continent, while the low activity concentrations tended to arrive via marine air masses from the North Atlantic. Indications of correlation of atmospheric boundary layer height with super( 210)Pb activity concentration were found.