NUKLEONIKA 2004, 49(4):167-171
Henryk Bem1, Marcin Olszewski1, Maria Bysiek2, Tadeusz Gluba3
1 Institute of Applied Radiation Chemistry, Technical University of Lodz,
36 Żwirki Str., 90-924 Lodz, Poland,
2 Central Laboratory for Radiological Protection,
7 Konwaliowa Str., 03-194 Warsaw, Poland,
3 Faculty of Process and Environmental Engineering,
Technical University of Lodz, 175 Wólczańska Str., 90-924 Lodz, Poland
The network of high volume aerosol samplers type ASS-500 in Poland, established mainly for monitoring
radionuclides of artificial origin, offers also a unique opportunity for measuring natural radionuclide
concentrations in ground-level air. Recounting of the closed (sealed) filters after a one month period,
necessary for establishing radioactive equilibrium between 226Ra and 222Rn,
as well as its short-lived decay products, remarkably improves the accuracy of 226Ra
determination. The Currie’s average detection and determination limits (with 10% relative accuracy)
calculated for 226Ra for 160,000 s counting time and combined with the average filtered
air volume of 60,000 m3 were 0.3 and 1.2 mBq/m3,
respectively. The observed 226Ra concentrations in air in Lodz during the half year
collection period, including parts of winter and summer seasons, were always above the detection limit
and ranged from 0.76 to 2.75 mBq/m3. 226Ra, present in
the ground level air mainly as a result of resuspension from the top layer of soil and fly ash
emissions from coal burning, was used for rough estimation of the contribution of the coal
combustion to the total suspended particulate matter. On the basis of available data for 226Ra
content in the soil and fly ashes for the Lodz region of Poland, the calculated coal combustion input
to the total air suspended particulate matter ranged from 8 to 39%.