Radioactivity in air and precipitation at Risø

Radiocaesium and radiostrontium concentrations in air have been followed at Risø over the latest 5 decades. Air filter samples are measured on a weekly basis by gamma spectrometry to determine ¹³⁷Cs concentrations, and ⁹⁰Sr in air filter samples is determined bi-annually. The time-series show comparatively high levels over the first decades from atmospheric nuclear bomb tests, the largest of which were made before 1963, where the superpowers stopped their atmospheric test programmes. The Chernobyl accident peak (1986) is also distinct for both radionuclides, although the ratio between air concentrations of ⁹⁰Sr and ¹³⁷Cs was some 0.2-0.3 near Chernobyl, but only about 0.02 in Denmark, due to differences in aerosol characteristics. Over decades, Risø National Laboratory has also measured ⁹⁰Sr and ¹³⁷Cs concentrations in precipitation collected monthly in rain samplers.

	Strontium-90 in ground level air at Risø, 1957-2009
	Caesium-137 in ground level air at Risø, 1957-2009
	Caesium-137 in precipitation at Risø, 1978-2009
	Strontium-90 in precipitation at Risø, 1960-2009

Page updated by 25.08.2009

Kasper Grann Andersson
Senior Scientist
Radiation Research (NUK)
Dir tel+45 46774173