Protection from Radon
1. Homeowners in the UK are being urged to take extra precautions to protect themselves from radon, the naturally occurring radioactive gas produced by the decay of uranium 238, which is present throughout the Earth’s crust. Radon has been called the worst environmental pollutant. A 5-fold increase in the number of homes officially designated at risk from the legal gas, which seeps out of the ground causing more than 1000 deaths a year, has just been announced by the Health Protection Agency (HPA). The Agency has just announced new standards to lessen exposure to radon, the harm from is estimated to be 1,100 deaths a year from lung cancer alone. The new “target level” of exposure of 100 becquerels per cubic metre is half the existing “action level” of 200 bcq.
2. Research over the past 20 years has shown that there is no “safe” level of radon. It exposes children in affected homes to higher levels of radiation than workers at the Sellafield nuclear reprocessing plant. Altho the risks are higher in the worst-affected homes, about 90% of deaths from radon occur in homes below 200 bcq, because there are many more of them. About 100,000 UK homes have radon levels over 200 bcq and between 500,000 and 600,000 have levels over 100 bcq. Radon levels are highest in houses on Dartmoor in Devon and in Cornwall, which are built on granite, in ports of Wales, the East Midlands, and the Pennines. The gas seeps into buildings through cracks in the foundations.
3. Sealing the foundations of new homes with gas-resistant membranes, which cost about £100,000 is the basis of current policies. In existing buildings owners are advised that “a radon sump” can be created by digging below the foundations and using a fan and pipe to blow the gas to the outside, but they have to meet the cost of about £1000. It is worth remembering these and other environmental factors in epidemiological studies and regional comparisons in connections of, say, smoking in cancer of lung and breast.