Review of recent radon research in Ireland, OPTI-SDS project and its impact on the National Radon Control Strategy

Using geogenic radon potential to assess radon priority area designation, a case study around Castleisland, Co. Kerry, Ireland

Globally, indoor radon exposure is the leading cause of lung cancer in non-smokers and second most common cause after tobacco smoking. Soil-gas radon is the main contributor to indoor radon, but its spatial distribution is highly variable, which poses certain challenges for mapping and predicting radon anomalies. Measurement of indoor radon typically takes place over long periods of time (e.g. 3 months) and is seasonally adjusted to an annual average concentration. In this article we investigate the suitability of using soil-gas radon and soil-permeability measurements for rapid radon risk assessments at local scale. The area of Castleisland, Co. Kerry was chosen as a case study due to availability of indoor radon data and the presence of significant radon anomalies. In total, 135 soil-gas and permeability measurements were collected and complemented with 180 indoor radon measurements for an identical 6 km² area. Both soil-gas and indoor radon concentrations ranged from very low (<10 kBqm^-3, 0.1 Bqm^-3) to anomalously high (>1433 kBqm^-3, 65,000 Bqm^-3) values. Our method classifies almost 50% of the area as a high radon potential area, and allows assessment of geogenic controls on radon distribution by including other geological variables. Cumulatively, the percentage of indoor radon variance explained by soil-gas radon concentration, bedrock geology, subsoil permeability and Quaternary geology is 34% (16%, 10%, 4% and 4% respectively). Soil-gas and indoor radon anomalies are associated with black shales, whereas the presence of karst and geological faults are other contributing factors. Sampling of radon soil-gas and soil permeability, used in conjunction with other geogenic data, can therefore facilitate rapid designation of radon priority areas. Such an approach demonstrates the usefulness of high-resolution geogenic maps in predicting indoor radon risk categories when compared to the application of indoor radon measurements alone. This method is particularly useful to assess radon potential in areas where indoor radon measurements are sparse or lacking, with particular application to rural areas, land rezoned for residential use, or for sites prior to building construction.

An investigation of a passive opened top-end pipe as an alternative solution for passive soil depressurisation systems for indoor radon mitigation

This study carried out a series of large-scale experimental tests and numerical simulations to investigate the performance of a passive opened top-end pipe as an alternative solution for passive soil depressurisation systems for indoor radon mitigation. Measurements were conducted in terms of wind velocity, extracted air velocity and negative pressure at the sump-end inside the pipe. Investigations were performed with controlled and natural wind conditions. Test results confirmed that the passive opened top-end pipe can be used as an alternative solution for indoor radon concentration mitigation at low additional construction cost. However, the extracted air velocity and negative pressure were found to fluctuate when tested under natural wind conditions. This fluctuation would reduce the effectiveness of the performance of the passive pipe. To reduce this fluctuation, a novel static ventilator has been developed and can be added on the top-end of the pipe.

RESEARCH ON PASSIVE SOIL DEPRESSURIZATION SYSTEMS: STATE OF THE ART AND LAB TEST ON-GOING

There is strong evidence both internationally and in Ireland that the correct installation of passive prevention systems in new buildings is the most cost-effective way of protecting the population against radon. Previous work considering membranes, granular fill material in the aggregate layer beneath the slab and sump system has been conducted in Ireland to improve the protection of buildings from radon. The implications of research on passive sumps potential to reduce radon concentrations are significant, as if it can be shown that the installation of passive sumps in Irish building is effective; this could constitute a low-cost, passive, sustainable method for minimizing radon levels in buildings. On-going experimental tests investigating the performance of different common cowls used for passive soil depressurization systems are presented, in addition to the impact of different vertical heights and horizontal lengths of pipe with a number of bends investigated.