Radon Gas – a general guide
Much of Cornwall is designated as a radon affected area. This means that at least 1% of the domestic properties have a radon level at or above the action level of 200 Becquerels per cubic metre (Bq/m-3).
This action level was set on advice from the National Radiological Protection Board (NRPB) and this recommendation has been endorsed by the Government. The action level is 10 times the national average for domestic properties.
Radon comes from minute amounts of uranium present in all earth materials. It is the largest source of natural radiation that we encounter and accounts for around 50% of all the radiation we are exposed to. Although radon is thought by many to be only associated with areas built on granite, it is in fact present in most parts of the UK. It is true to say however that the South West is the most affected area in the UK. Radon is also found in other countries including Sweden, the other Nordic Countries, Germany and USA.
When radon enters our homes and either the ventilation is poor or excessively large amounts are present, it can build up to high concentrations.
If you want to know how much radon is present in your home than it is possible to order radon detection kits. The only reliable guide to the level of radon in a building is a measurement over a period long enough to average out short-term variations in radon levels – this should ideally be three months. It is possible to order a home measurement pack from UK radon.
Where a property is found to be above the action level, PHE suggests that remedial work is undertaken to reduce the levels. The solution very much depends upon the radon level and property construction. At some of the lower levels, the solutions can be very simple and cheap to install. This could be the replacement of old air bricks with the more efficient modern ones. If you are installing new windows, then think about specifying trickle vents to improve the ventilation. At the higher levels, it is generally felt that some form of mechanical system would be necessary.