Radon in the Ribble Valley

1. BACKGROUND

Radon is a naturally occurring radioactive gas which is formed by the decay of small amounts of uranium present in all rocks and soils. It has no taste, smell or colour.

Outdoors, radon is diluted to very low levels and is of little concern. However, indoors radon is drawn in through cracks and gaps in the ground floor of properties and levels of the gas can build up to a high concentration. In such cases, radon does pose a serious risk to health.

People who are exposed to high levels of radon are more likely to get lung cancer (much more if they are smokers as well). This is because radon decays to minute radioactive particles which can be breathed in, thus damaging the lining of the lungs and irradiating the surrounding tissue.

It is estimated that radon causes 1,000-2,000 lung cancer deaths each year in the United Kingdom.

2. HOW IS RADON DETECTED AND MEASURED

Radon is normally measured, over a three month period, using two small pots provided by the Health Protection Agency. Its concentration is measured in becquerels per cubic metre of air (Bqm-3) and the HPA recommends that radon levels should be reduced in homes where the annual average concentration is more than 200 Bqm-3.

This figure is known as the Action Level and has been endorsed by the Government. The average level in the UK is 20Bqm-3.

One of the main problems for local authorities is trying to identify exactly which properties may have high concentrations of the gas, as levels can fluctuate significantly between adjoining dwellings. This may be due to a number of factors, including the geological characteristics of the ground underneath buildings, details of construction and the habits of the occupants.

Simple measures, such as increasing ventilation within a property are often successful in reducing levels of the gas. However, in exceptional cases, a radon sump may be required (details of which can be obtained from the Building Research Establishment.

3. RADON AFFECTED AREAS

During the mid 1990s the National Radiological Protection Board, predecessor of the HPA, carried out an extensive national sampling programme for radon in order to establish the extent of the problem in England. The results of this survey were then used to help produce the Radon Atlas of England, first published in 1996 and revised in 2002.

Both of these documents were extremely useful as they contained radon probability maps for the whole of England, dividing the country into 5km squares of the Ordnance Survey Grid. The Atlas identified areas, known as Radon Affected Areas, where 1% or more of homes are estimated to be at or above the Action Level.

Within the Ribble Valley area, six Radon Affected Areas were identified and these included the villages of Grindleton, Sawley, Bolton by Bowland, Holden, Newton, Dunsop Bridge, Paythorne, Newsholme and Horton.

All of these, with the exception of Horton (3-5% level), were drafted into the lowest risk band of 1-3% ie up to 3% of homes within that area were estimated to be at or above the Action Level.

4. ACTION TAKEN BY RIBBLE VALLEY BOROUGH COUNCIL (RVBC)

Since 1999, RVBC have surveyed a total of 198 properties for radon gas. The majority of these properties were selected either because of their location within a Radon Affected Area or due to the underlying geology.

The results are summarised below:

Radon Measurements in Bqm-3 

The significant findings of these results reveals that out of 89 dwellings surveyed within the Grindleton area, 11 exceeded the Action Level, whilst a further 23 had an elevated radon concentration of between 100 and 200Bqm-3.

5.  2007 RADON ATLAS 

On 12 November 2007 an updated Radon Atlas was published jointly by the Health protection Agency (HPA) and the British Geological Survey (BGS).  This document is available as a free download from the HPA website www.hpa.org.uk/radiation.

This revised atlas differs significantly from its predecessors in that Radon Affected Areas are now grouped into 1km grid squares and the atlas shows the highest probability banding found in each 1km grid square. It combines the results of an extensive national sampling programme with detailed geological maps, which has resulted in a large increase in the number of designated Radon Affected Areas (both locally and nationally). More significantly, over 90% of the Ribble Valley is now designated as a Radon Affected Area.

However, the main advantage of this advanced data set is that it provides a radon probability banding for each individual property in England and Wales, with a valid postcode.

Therefore, for a fee of £3.53 (inc VAT) any individual can carry out a search for a particular property on the new UK radon website www.ukradon.org. The results of this search would reveal:

1) Whether a property is located in a Radon Affected Area.

2) The estimated probability of the property being above the Action Level.

3) Whether radon protection is required for new buildings and extensions at the property location.