[Radiation exposure of the respiratory tract to radionuclides in the environment]

Epidemiological investigations concerning lung cancer mortality of miners in radioactive underground climate have clearly resulted that the alpha-radiation of radon daughters emerging from the geological formations represent the causative factor for the accumulation of these lung cancers. The same radionuclides are also important as components of the natural radiation exposure, above all in houses built with radium containing material. Estimations of the risk referring to this form of natural radiation exposure allow rough calculation of its role for lung cancer incidence in GDR. Accordingly about 10%, in men 5% and 50% in females, of the cases of lung cancer may be caused by the natural inhalative radiation exposure. Natural radioactivity by coal and coal ashes as well by tobacco smoke are shortly outlined in their additional significance. The measures of radiation protection legal in GDR to limit inhalative exposure, above all in buildings, by supervision and selection of building material are described.