Onderzoek naar radioactiviteit in luchtstof te De Bilt. Resultaten over 1989
The radioactivity of airdust-samples. Results for De Bilt for 1989.
Koolwijk AC , Mattern FCM , Drost RMS
RIVM Rapport 243301002
Abstract niet beschikbaar
In 1989 airborne particles were daily sampled, using a sampling-period of 24 hours. After 5 days decay of the short-lived daughters of radon and thoron gross-alpha, gross-beta and gross-gamma activities were measured. The yearly average of gross-alpha activity was 0.04 mBq/m3, of gross-beta activity 0.18 mBq/m3, and of gross-gamma activity 0.19 mBq/m3. These mean levels are quite similar to those of 1988. Applying gamma-spectroscopy no artificial radionuclides could be detected in airborne particles. Only the natural activationproduct Be-7 was detectable. The yearly average was 1.2 mBq/m3 and the contribution to the gross-gamma activity was estimated at approximately 0.12 mBq/m3. The major contributions to gross-alpha and gross-beta activity in airborne particles are most likely explained by natural Po-210 resp. Pb-210/Bi-210.