Cost-effectiveness of radon remediation programmes in the UK in the 2020s.

Radon, a gaseous radioactive decay product of naturally-occurring uranium is widely distributed in the environment in rocks and soils and, in certain circumstances, can accumulate in the built environment. Initial studies confirmed a direct link between exposure to both radon gas and its short-lived radioactive progeny, and increased lung-cancer incidence, and demonstrated that radon levels in domestic housing can be sufficiently high to expose occupants to increased risk of lung-cancer. Subsequent studies worldwide have shown that it is cost-effective to detect and reduce domestic radon levels in order to reduce this risk. Recent advances in the early detection of lung-cancer, coupled with the development of improved treatment procedures, have progressively improved survival from the disease, with the numbers surviving at 5 years doubling over recent years, during which period the real costs of lung cancer treatment have risen by around 30%. In the meantime, however, in addition to radon and tobacco-smoke, other airborne pollutants have been identified as risk-factors for lung-cancer. This paper reviews both these actual developments and anticipated future trends, and concludes that since these advances in diagnosis and treatment of lung-cancer have had only a modest effect on cost-effectiveness, it is still important to conduct radon monitoring and remediation programmes. While the general increase in life-expectancy improves the cost-effectiveness of radon remediation programmes significantly, reducing tobacco-smoking incidence reduces that cost-effectiveness but with the overall benefit of reducing radon-related lung-cancers. The challenge remains of encouraging affected householders to remediate their homes to reduce radon levels.

Exploring the relationship between social deprivation and domestic radon levels in the East Midlands, UK.

The natural radioactive gas radon is widely present in the built environment and at high concentrations is associated with enhanced risk of lung-cancer. This risk is significantly enhanced for habitual smokers. Although populations with higher degrees of social deprivation are frequently exposed to higher levels of many health-impacting pollutants, a recent study suggests that social deprivation in the UK is associated with lower radon concentrations. The analysis reported here, based on published data on social deprivation and domestic radon in urban and rural settings in the English East Midlands, identifies a weak association between increasing deprivation and lower radon areas. This is attributed to the evolution of the major urban centres on low-permeability, clay-rich alluvial soils of low radon potential. In addition, the predominance of high-rise dwellings in towns and cities will further reduce average exposure to radon in populations in those areas.

An assessment of the effectiveness of UK building regulations for new homes in Radon Affected Areas.

Radon, a naturally occurring radioactive gas generated underground by radioactive decay of nuclides contained in certain types of rocks, can concentrate inside buildings, where it poses the second-largest risk factor for lung cancer, after smoking. The highest concentrations of domestic radon in the UK occur in the south-western counties of Devon and Cornwall, but certain areas in Northamptonshire and surrounding counties in the English Midlands also have high levels. It has been shown that it is possible both to reduce the radon concentrations in existing houses and to build new homes with appropriate protection. Since 1999, the UK's Building Regulations have specified that all new homes should be built with a combined radon-proof/damp-proof membrane plus, in Radon Affected Areas, a sump under the building. However, the building regulations do not require that the radon level is measured once the house is built and so there is little information on the effectiveness of these measures. Builders generally do not mention radon, and when asked, just confirm that their houses are built to current standards. To better understand the efficacy or otherwise of the currently mandated radon-protection measures, a cross-sectional investigation was carried out in 26 new housing developments in high-radon areas in Northamptonshire. In a targeted mail-shot, 1056 householders were invited to apply for a free radon test; 124 replied (11.7%). In total, 94 pairs of detectors were returned (70.1% of responders), of which two were spoiled, giving a total of 92 results. Following processing and seasonal correction, the arithmetic mean radon concentration in the target houses was 45% of the arithmetic mean radon concentration in existing houses in the postcode sectors where the houses were built and were approximately log-normally distributed. No results exceeded the UK Action Level of 200 Bq. m-3 but three were above the Target Level of 100 Bq. m-3. The results suggest that the radon-proof membranes in general ensure that radon concentrations in new homes constructed in accordance with the Building Regulations in Radon Affected Areas (RAAs) are satisfactorily low. However, there is a very small statistical probability that levels in a small number of homes will be close to or above the Action Level, particularly in areas of high radon potential. As a result, the Public Health England (PHE) recommendation for testing in the first year of occupation should be adopted as a legal requirement.

Is environmental radon gas associated with the incidence of neurodegenerative conditions? A retrospective study of multiple sclerosis in radon affected areas in England and Wales.

To test whether an association exists between radon gas concentration in the home and increased multiple sclerosis (MS) incidence, a retrospective study was undertaken of MS incidence in known areas of raised domestic radon concentration in England and Wales, using The Health Improvement Network (THIN) clinical research database. The study population comprised 20,140,498 person-years of clinical monitoring (males: 10,056,628: 49.93%; females: 10,083,870: 50.07%), representing a mean annual population of 2.5 million individuals. To allow for the possible latency of MS initiation following exposure, data extraction was limited to patients with at least five years registration history with the same GP practice before first diagnosis. Patient records were allocated to one of nine radon concentration bands depending on the average radon level in their postcode sector. MS incidence was analysed by searching for patients with first MS diagnosis over the eight calendar years 2005-2012 inclusive. 1512 new MS cases were diagnosed, 1070 females, 442 males, equivalent to raw incidence rates of 7.51, 10.61 and 4.40 per 10(5) person-years respectively, comparable to previously reported results. Of these new cases, 115 could be allocated to one of the radon bands representing high radon areas. Standardising to the UK 2010 population, excess relative risk (ERR) figures for MS were calculated for each radon band. Linear regression of ERR against mean band radon concentration shows a positive gradient of 0.22 per 100 Bq·m(-3) (R(2) = 0.25, p = 0.0961) when forced through the origin to represent a linear-no-threshold response. The null hypothesis falls inside the 95% confidence interval for the linear fit and therefore this fit is not statistically significant. We conclude that, despite THIN sampling around 5% of the population, insufficient data was available to confirm or refute the hypothesised association between MS incidence and radon concentration.

Small area mapping of domestic radon, smoking prevalence and lung cancer incidence--A case study in Northamptonshire, UK.

Smoking and radon both cause lung cancer, and together the risk is significantly higher. UK public health campaigns continue to reduce smoking prevalence, and other initiatives identify houses with raised radon (radon-222) levels and encourage remedial action. Smoking prevalence and radon levels in the UK have been mapped at Primary Care Trust level. This paper extends that work, using a commercial socio-demographic database to estimate smoking prevalence at the postcode sector level, and to predict the population characteristics at postcode sector level for 87 postcode sectors in Northamptonshire. Likely smoking prevalence in each postcode sector is then modelled from estimates of the smoking prevalence in the different socio-economic groups used by the database. Mapping estimated smoking prevalence, radon potential and average lung cancer incidence for each postcode sector suggested that there was little correlation between smoking prevalence and radon levels, as radon potential was generally lower in urban areas in Northamptonshire, where the estimates of smoking prevalence were highest. However, the analysis demonstrated some sectors where both radon potential and smoking prevalence were moderately raised. This study showed the potential of this methodology to map estimated smoking prevalence and radon levels to inform locally targeted public health campaigns to reduce lung cancer incidence.

A critical analysis of climatic influences on indoor radon concentrations: Implications for seasonal correction.

Although statistically-derived national Seasonal Correction Factors (SCFs) are conventionally used to convert sub-year radon concentration measurements to an annual mean, it has recently been suggested that external temperature could be used to derive local SCFs for short-term domestic measurements. To validate this approach, hitherto unanalysed radon and temperature data from an environmentally-stable location were analysed. Radon concentration and internal temperature were measured over periods totalling 1025 days during an overall period of 1762 days, the greatest continuous sampling period being 334 days, with corresponding meteorological data collected at a weather station 10 km distant. Mean daily, monthly and annual radon concentrations and internal temperatures were calculated. SCFs derived using monthly mean radon concentration, external temperature and internal-external temperature-difference were cross-correlated with each other and with published UK domestic SCF sets. Relatively good correlation exists between SCFs derived from radon concentration and internal-external temperature difference but correlation with external temperature, was markedly poorer. SCFs derived from external temperature correlate very well with published SCF tabulations, confirming that the complexity of deriving SCFs from temperature data may be outweighed by the convenience of using either of the existing domestic SCF tabulations. Mean monthly radon data fitted to a 12-month sinusoid showed reasonable correlation with many of the annual climatic parameter profiles, exceptions being atmospheric pressure, rainfall and internal temperature. Introducing an additional 6-month sinusoid enhanced correlation with these three parameters, the other correlations remaining essentially unchanged. Radon latency of the order of months in moisture-related parameters suggests that the principal driver for radon is total atmospheric moisture content rather than relative humidity.