Hot particles in air filters collected in Finland immediately after the Chernobyl accident

Following the accident at the Chernobyl nuclear power plant on 26 April 1986, about 2 7 10^18 Bq of condensable radioactive materials were released, the majority of which was deposited in Europe. Most of the released radioactive material was in particulate form, whereas noble gases and most of iodine were in gaseous form. Sometimes their activities may be so high that even a single particle may cause a severe health hazard. Radioactive particles released from Chernobyl have been described by many as \u201chot particles\u201d where \u201chot\u201d is synonymous with \u201chighly radioactive\u201d. In the Chernobyl accident most of the particulate material was deposited within 20 km of the plant, but about one-third was transported even thousands of kilometres. Air masses originating from Chernobyl on 26 April 1986 arrived in Finland very early after the accident. Identification of the hot particles in filters collected in Helsinki Finland between 27-29 April 1986 was done by autoradioagraphy technique (Cyclone Plus of PerkinElmer) in the University of Milano, Italy. Morphology and elemental information for particle characterization will be given by SEM analysis. Elemental distribution and structure information will be given by \u3bc-XRF analysis