Radon remediation: an analysis of dose-reduction, durability and effectiveness

Radon is a colourless, odourless, inert, radioactive gas found in Group 8 of the Periodic Table; it is formed by the decay of uranium in soils and rocks. The half-life of radon is 3.8 days. Radon, in the built environment, is the second largest cause of lung cancer after cigarette smoking and is responsible for 3-5% of the UK cancer deaths. Radon can accumulate in workplaces to levels (400 Bq.m3), above which action is required under UK legislation by employers to remediate so as to reduce levels and lower the risk to human health. The remediation and post-remediation research programme in the NI-IS properties in Northamptonshire is perhaps the most mature in the UK, commencing in 1993. This thesis includes a review of the main remediation projects in National Health Service (NHS) properties in Northamptonshire. Data has been obtained from a range of sources, post-remediation, to enable a cost-effectiveness assessment. Using direct radon measurements and questionnaires, to determine occupancy, dose reduction has been calculated for all members of staff in the remediated venues. The reduction in dose is lower than the reduction in radon. The trends in radon levels post-remediation have been investigated night-time levels are reduced more than daytime levels and this has a clear implication for dose to staff The effective lifetime of the remediation systems has been investigated. Remediation systems, operated through a clear management system, have been found to remain effective up to eight years after installation. A Decision Support System to support radon management in the workplace is proposed as well as suggestions for future research