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

K Isakar, M Kiisk, E Realo, S Suursoo
2016 Proceedings of the Estonian Academy of Sciences  
As the first study of long-term atmospheric 210 Pb in Estonia, the activity concentration and possible origins of the nuclide were monitored at Tõravere, South Estonia, and Narva-Jõesuu, North-East Estonia, from 2001 to 2008. Activities of 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 -3 to 2.76 mBq m -3 (median 0.45 mBq m -3 ) for Tõravere and from 0.08 mBq m -3
more » ... from 0.08 mBq m -3 to 2.53 mB m -3 (median 0.43 mBq m -3 ) for Narva-Jõesuu. No significant correlation between the 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 210 Pb concentrations from the two sampling sites was present. Back-trajectory calculations made with the METEX software showed clearly that high 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 210 Pb activity concentration were found.
doi:10.3176/proc.2016.4.11 fatcat:an4rpqhxjrdchn3ej4644wpi4a