HC Deb 10 January 1989 vol 144 c501W
Mr. Redmond

To ask the Secretary of State for the Environment what is the national average of Radon radiation concentrations.

Mrs. Virginia Bottomley

A national survey carried out by the National Radiological Protection Board found an average concentration of 20.5 becquerels per cubic metre of air in dwellings.

Mr. Redmond

To ask the Secretary of State for the Environment what is the design level for buildings in a Radon radiation area.

Mrs. Virginia Bottomley

The Government's advisers on radiological protection matters, the National Radiological Protection Board (NRPB), recommended that exposure to radon daughters in the home should be limited to 5 millisieverts a year. The design level, which was recommended by the NRPB, reflects international consensus on this matter as well as the views of the Royal Commission on Environmental Pollution.