Radon

Introduction

Radon is a radioactive gas that occurs naturally. It has no taste, smell or colour and requires special devices to detect it. It is found everywhere but usually in insignificant quantities. Radon rises from the soil into the air. Outdoors, radon is diluted and the risk it poses is negligible. It is when radon stays in enclosed spaces that concentrations can build up. Radon levels are higher in some parts of the country than others because of the geology of the area. The National Radiological Protection Board (NRPB) has been able to identify those areas of the country where radon levels are higher than normal and has produced an atlas outlining radon-affected areas.

When radon concentration is high, over time it poses a serious risk to health. Health studies from around the world have linked radon and lung cancer (Darby et al., 1998, 2001; Lubin and Boice, 1997; Wichmann et al., 1998; Lubin et al., 1995). Radon is believed to be the second most important cause of lung cancer after smoking (active smoking accounts for 30 per 1,000 deaths, radon and passive smoking 3 and 0.3 respectively). The NRPB estimates that 5% of lung cancer deaths in the UK are attributable to radon (NRPB, 2000) although the lung cancer caused by radon cannot be distinguished from the lung cancer caused by smoking.

Radon in the home

A recent study carried out by the former Imperial Cancer Research Fund has confirmed that exposure to radon in the home can lead to an increase in the risk of lung cancer (Darby et al., 1998; see also Parliamentary Office of Science and Technology, 2001). Radon levels in buildings depend on the way they are constructed and used. When air containing radon rises from the soil and rocks beneath buildings it can find ways in, mainly through cracks in floors and walls, and gaps around service pipes. The NRPB measures radon levels in becquerels per cubic metre (Bq/m3) of air, and has advised the government that the level of 200 Bq/m3 in homes should be considered the level at which action should be taken to reduce radon concentration. This is known as the Action Level.

Testing for radon

The NRPB has devised a simple and confidential test to measure radon levels in the home. The detector is a piece of spectacle lens plastic in a protective shell and is about the size and shape of a small doorknob. Two test detectors are sent through the post by the NRPB and one is placed in the living room and the other in an occupied bedroom. After three months the detectors are returned and analysed by experts in accredited laboratories. Measurements should not be made in properties that are unoccupied or undergoing building works. A small charge is made for the detectors and covers supply, processing and provision of information and advice; as of April 2002 the charge was £30.80 + VAT for two detectors.

Remedial measures

Homes that have been identified as having particularly high radon levels can undertake simple, inexpensive and effective measures to reduce radon to acceptable levels. The work can usually be carried out by the homeowner or by a builder and would normally entail minor construction work and possibly the installation of a fan system to keep radon from entering the property. Types of remedial action are listed in the table overleaf.

Objectives of radon interventions

Householders whose homes are at or above the radon Action Level should undertake remedial work and thus reduce the risk of lung cancer. The government radon programme aims to increase the number of householders who know that their radon levels exceed the Action Level and also the proportion who remediate. To achieve this, it will be necessary to raise awareness of the dangers of radon in the home.
radon

National versus local radon programmes

The Department of the Environment, Transport and the Regions (DETR) (now the Department for Environment, Food and Rural Affairs, DEFRA) has been running a national radon measurement programme for over a decade aimed at addressing the lifetime risk posed to people’s health by radon gas in the home (DETR, 2000a). To date, the NRPB has carried out some 400,000 tests for radon and results indicate that some 40,000 homes are above the radon Action Level. However, only 10-20% of these households have taken any action to reduce radon levels in their homes.

To increase the levels of remediation the then DETR initiated a pilot programme involving three local
authorities in radon-affected areas (DETR, 2000a). This was to test the assumption that householders would be more likely to respond positively to an approach by their local authority than to an approach by central government or a national agency. Activities undertaken by the three pilot programmes included: awareness raising, working with local builders, targeting and approaching householders and delivering advice and support to those who responded. As a consequence of these activities, response rates were generally high and remediation was speeded up and increased in all three areas, with the total of remediated properties increasing by up to 100% on previously achieved numbers. A number of key factors contributed to the success of the pilot studies and included local and proactive delivery, effective targeting, appropriate timing of publicity, optimum use of technical expertise and sustained support and follow-up. The results from the evaluation of the three local authority pilot studies confirmed the expectation (stemming in part from previous qualitative research) that generating responses to awareness raising and motivating people to undertake remedial action is best undertaken at the local, rather than the national level (DETR, 2000a).

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