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1 2004

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Evaluation of the coal combustion input to the 226Ra ground-level air concentration in the Lodz city, Poland

Bem H., Olszewski M., Bysiek M., Gluba T.

Nukleonika

2004

Vol. 49, nr 4

167-171

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 mi Bq/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 mi Bq/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%.