The radon reality

Radon is a naturally occurring radioactive gas that originates from the decay of uranium in rocks and soils. It is colourless, odourless and tasteless. Having diffused to the land surface, radon is then normally diluted in air to harmless concentrations.

However, when it enters an enclosed space such as a home, an office, a workshop or other building, it may accumulate to high concentrations, which often occur mainly in basements and ground-floor locations. High radon concentrations are considered a health hazard because it and its radioactive decay products, can when inhaled provide a radiation dose that may damage cells in the lungs. Long-term exposure to radon gas is implicated as one of the factors leading to an increased risk of lung cancer.

The reference level for long-term exposure to radon in homes, above which the need for remedial action should be considered, is 200 Bq/m- 3 and for workplaces, in which people generally spend less time, the comparable level is 400 Bq/m-3.

The Radiological Protection Institute of Ireland (RPII) is the national organisation charged with regulatory monitoring and advisory responsibilities in matters pertaining to radiation. The Institute has conducted a national survey, based on a 10 km2 grid, of radon concentrations in home. Grid squares that have been determined as 'High Radon Areas' are those where more than 10% of samples exceed the Institute's Reference Level for homes of 200 Bq/m-3.

ESB Shared Services has addressed the potential radon risk issue through a programme of systematic radon assessments at all occupied commercial premises based on indicative information provided by the RPII. The programme commenced in 2004 and final measurements were recently completed. The programme involved:

• The placement of radon detectors within each location in accordance with guidelines issued by the RPII for a standard three-month assessment period
• Analysis of the detectors by an approved laboratory
• Engagement of specialist advisers to evaluate and recommend appropriate remedial measures
• Communication of results to staff where the workplace national Reference Level (400 Bq m-3) was exceeded

Nonetheless, minor remediation works - involving the installation of a radon sump and associated electric fan to increase under-floor ventilation - was undertaken in all nine premises. All locations were subject to re-test to confirm remedial works were effective and subsequent test results gave readings in all cases that were well below the reference level of 400 B/qm-3

For homeowners, the RPII advises that you have a radon measurement carried out by them or another radon measurement service who placing two small detectors. One detector is placed in a bedroom, the other in a living room. At the end of the threemonth measurement period, the detectors are returned for analysis. For general information on radon, its health effects and radon measurements contact the RPI on free phone 1800 300 600.

Full information, including a list of radon remediation companies, can be found on www.rpii.ie. For further information on the technical aspects of remediation options, contact the building control officer in your Local Authority or the Building Standards section in the Department of the Environment, Heritage and Local Government on 01 8882000.