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Press release from the NRPB
Ann. nucl. Energy, Vol. 13, No. 2, p. 107, 1986
Pergamon Press Ltd. Printed in Great Britain
PRESS RELEASE F R O M THE N R P B R A D O N IN HOUSES: NRPB SURVEYS
Radon, a naturally-occurring radioactive gas, is the most significant source of radiation exposure in the country and there are marked regional variations. These are the conclusions drawn from surveys by the NRPB. The provisional results are announced in a paper* presented to the Conference of the National Society for Clean Air at Scarborough on 17 October. Public concern is most frequently expressed about radioactive discharges from the nuclear industry. Yet only 0.1~o of the average radiation dose in the U.K. is due to this practice. Around 90~ is caused by natural sources--cosmic rays, 7-rays, radioactivity in diet and radon in air. Radon gas is created by the trace quantities of uranium in the ground and in building materials. The gas moves through rock and soil or brick and concrete and enters the atmosphere. Levels in outdoor air are low, but radon accumulates indoors because of restricted ventilation with fresh air. Radon undergoes radioactive decay into solid products, which are also radioactive, and attach themselves to dust particles in the air. When these are inhaled, they irradiate the lung. The NRPB has conducted a national survey of radon in dwellings and several smaller studies in regions where levels were expected to be above the national average. Higher levels are possible particularly in and around granite areas where the uranium quantities are also higher than average. Provisional results from the national survey show that radon
* Human Exposure to Radon Decay Products, by A. D. WRIXON.
107
concentrations in London are about half the average value, in eastern England about average and in southwest England about three times the average. The highest regional levels were found in Cornwall, with typical values around 10 times the national average, and specific values over 10 times higher still. Elevated levels were also found in Devon and in the Pennine region. Contrary to expectation, levels in Aberdeen were below the national average, probably because of the type of granite and local building practices. There is no direct evidence that exposure to radon decay products in the home causes harm to human beings. There is evidence, however, that the prolonged exposure of uranium and other miners to high levels of radon decay products underground causes lung cancer. It is therefore necessary to make the cautious assumption that there might be a proportionate risk to the public at the levels of indoor exposure found. The NRPB is therefore working with the Building Research Establishment to develop methods for reducing radon levels. Techniques being studied include increasing the ventilation, preventing the gas from entering the home and extracting the gas under the floor. The NRPB is also considering whether to advise the Department of the Environment that remedial action should be considered for some existing dwellings and preventive action for new buildings in some regions. The suggestion that radiation standards might be necessary to limit exposures to radon decay products was endorsed by the Royal Commission on Environmental Pollution in its tenth report. Press enquiries: NRPB Information Office [Abingdon (0235) 831600], Matt Gaines ext. 410 [home: Oxford (0865) 52459], Gill Wilkinson ext. 514 [home: Abingdon (0235) 21211].
Pergamon Press Ltd. Printed in Great Britain
PRESS RELEASE F R O M THE N R P B R A D O N IN HOUSES: NRPB SURVEYS
Radon, a naturally-occurring radioactive gas, is the most significant source of radiation exposure in the country and there are marked regional variations. These are the conclusions drawn from surveys by the NRPB. The provisional results are announced in a paper* presented to the Conference of the National Society for Clean Air at Scarborough on 17 October. Public concern is most frequently expressed about radioactive discharges from the nuclear industry. Yet only 0.1~o of the average radiation dose in the U.K. is due to this practice. Around 90~ is caused by natural sources--cosmic rays, 7-rays, radioactivity in diet and radon in air. Radon gas is created by the trace quantities of uranium in the ground and in building materials. The gas moves through rock and soil or brick and concrete and enters the atmosphere. Levels in outdoor air are low, but radon accumulates indoors because of restricted ventilation with fresh air. Radon undergoes radioactive decay into solid products, which are also radioactive, and attach themselves to dust particles in the air. When these are inhaled, they irradiate the lung. The NRPB has conducted a national survey of radon in dwellings and several smaller studies in regions where levels were expected to be above the national average. Higher levels are possible particularly in and around granite areas where the uranium quantities are also higher than average. Provisional results from the national survey show that radon
* Human Exposure to Radon Decay Products, by A. D. WRIXON.
107
concentrations in London are about half the average value, in eastern England about average and in southwest England about three times the average. The highest regional levels were found in Cornwall, with typical values around 10 times the national average, and specific values over 10 times higher still. Elevated levels were also found in Devon and in the Pennine region. Contrary to expectation, levels in Aberdeen were below the national average, probably because of the type of granite and local building practices. There is no direct evidence that exposure to radon decay products in the home causes harm to human beings. There is evidence, however, that the prolonged exposure of uranium and other miners to high levels of radon decay products underground causes lung cancer. It is therefore necessary to make the cautious assumption that there might be a proportionate risk to the public at the levels of indoor exposure found. The NRPB is therefore working with the Building Research Establishment to develop methods for reducing radon levels. Techniques being studied include increasing the ventilation, preventing the gas from entering the home and extracting the gas under the floor. The NRPB is also considering whether to advise the Department of the Environment that remedial action should be considered for some existing dwellings and preventive action for new buildings in some regions. The suggestion that radiation standards might be necessary to limit exposures to radon decay products was endorsed by the Royal Commission on Environmental Pollution in its tenth report. Press enquiries: NRPB Information Office [Abingdon (0235) 831600], Matt Gaines ext. 410 [home: Oxford (0865) 52459], Gill Wilkinson ext. 514 [home: Abingdon (0235) 21211].