The ionizing radiation in dwellings related to the building materials.

Reports measurements in seven groups of town house in Gavle, Sweden of concentrations of radon and daughter products. Gives results with the type of building materials, the ventilation systems and air-change rates measured using nitrous oxide as a tracer gas. Gives formula for the permitted limits of radionucleides in building materials. Discussed results and concludes that the concentration of radon does not differ significantly from single family to multi-family houses.