Interpreting short and medium exposure etched-track radon measurements to determine whether an action level could be exceeded.

Radon gas is naturally occurring, and can concentrate in the built environment. It is radioactive and high concentration levels within buildings, including homes, have been shown to increase the risk of lung cancer in the occupants. As a result, several methods have been developed to measure radon. The long-term average radon level determines the risk to occupants, but there is always pressure to complete measurements more quickly, particularly when buying and selling the home. For many years, the three-month exposure using etched-track detectors has been the de facto standard, but a decade ago, Phillips et al. (2003), in a DEFRA funded project, evaluated the use of 1-week and 1-month measurements. They found that the measurement methods were accurate, but the challenge lay in the wide variation in radon levels - with diurnal, seasonal, and other patterns due to climatic factors and room use. In the report on this work, and in subsequent papers, the group proposed methodologies for 1-week, 1-month and 3-month measurements and their interpretation. Other work, however, has suggested that 2-week exposures were preferable to 1-week ones. In practice, the radon remediation industry uses a range of exposure times, and further guidance is required to help interpret these results. This paper reviews the data from this study and a subsequent 4-year study of 4 houses, re-analysing the results and extending them to other exposures, particularly for 2-week and 2-month exposures, and provides comprehensive guidance for the use of etched-track detectors, the value and use of Seasonal Correction Factors (SCFs), the uncertainties in short and medium term exposures and the interpretation of results.

The cost effectiveness of radon reduction programmes in domestic housing in England and Wales: the impact of improved radon mapping and housing trends.

In the UK, excessive levels of radon gas have been detected in domestic housing. Areas where 1% of existing homes were found to be over the Action Level of 200Bq·m(-3) were declared to be Radon Affected Areas. Building Regulations have been introduced which require that, for areas where between 3% and 10% of existing houses are above the Action Level, new homes should be built with basic radon protection using a membrane, and that, where 10% or more of existing homes exceed this level, new homes should be built with full radon protection. Initially these affected areas followed administrative boundaries, known as Counties. However, with increasing numbers of measurements of radon levels in domestic homes recorded in the national database, these areas have been successively refined into smaller units - 5km grid squares in 1999, down to 1km grid squares in 2007. One result is the identification of small areas with raised radon levels within regions where previously no problem had been identified. In addition, some parts of areas that were previously considered radon affected are now considered low, or no, risk. Our analysis suggests that the net result of improved mapping is to increase the number of affected houses. Further, the process is more complex for local builders, and inspectors, who need to work out whether radon protection in new homes is appropriate. Our group has assessed the cost-effectiveness of radon remediation programmes, and has applied this analysis to consider the cost-effectiveness of providing radon protection in both new and existing homes. This includes modelling the potential failure rate of membranes, and whether testing radon levels in new homes is appropriate. The analysis concludes that it is more cost effective to provide targeted radon protection in high radon areas, although this introduces more complexity. The paper also considers the trend in housing to a greater proportion of apartments, the regional variations in types of housing and the decreasing average number of occupants in each dwelling, and concludes that data and methods are now available to respond to the health risks of radon at a local level, in keeping with a general initiative to prioritise responses to health and social welfare issues at a more local level.

Posterior prolongation of the cartilaginous nasal septum: an under-utilised source of autologous graft material.

AIM: To assess the clinical and radiological characteristics of the posterior prolongation of the cartilaginous nasal septum, an under-utilised source of autologous cartilage for nasal reconstruction. MATERIALS AND METHODS: Consecutive patients undergoing primary, external approach rhinoplasty were included. The septal cartilage was assessed intra-operatively prior to routine harvest. Cartilage use was recorded and post-operative cosmesis noted. Computed tomography scans from a separate patient group, with no septal surgery, were used to assess septal cartilage dimensions. RESULTS: Of the 25 rhinoplasty patients studied, 24 had harvestable septal cartilage, with a posterior prolongation mean length ± standard deviation of 24.3 ± 8.40 mm, mean height of 4.33 ± 0.34 mm and mean width of 1.1 ± 0.35 mm. The mean post-operative cosmesis score was +2.41 ± 0.71 at a mean follow up of 45 ± 8.7 weeks. All 25 radiology patients had visible posterior prolongations on computed tomography (mean length, 18.1 ± 5.1 mm; mean height, 4.2 ± 1.1 mm; mean width 1.5 ± 0.63 mm). CONCLUSION: Harvesting of the posterior prolongation would increase by 25 per cent the cartilage area available for autologous grafts. Endoscopic guidance aids this process. Cartilage is most commonly used for overlay grafts, with good cosmesis. The posterior prolongation is demonstrated on computed tomography, although dimensions may be underestimated.

Lung-cancer reduction from smoking cessation and radon remediation: a preliminary cost-analysis in Northamptonshire, UK.

Domestic radon levels in parts of the United Kingdom are sufficiently high as to increase the risk of lung-cancer among residents. Public health campaigns in the county of Northamptonshire, a designated radon Affected Area with 6.3% of homes having average radon levels in excess of the UK Action Level of 200 Bq m(-3), have encouraged householders to test for radon and then, if indicated to be necessary, to carry out remediation in their homes. These campaigns have been only partially successful, since to date only 40% of Northamptonshire houses have been tested, and only 15% of those householders finding raised levels have proceeded to remediate. Those who remediate have been shown to have smaller families, to be older, and to include fewer smokers than the average population, suggesting that current strategies to reduce domestic radon exposure are not reaching those most at risk. During 2004-2005, the NHS Stop-Smoking Services in Northamptonshire assisted 2847 smokers to quit to the 4-week stage, the 15% (435) of these 4-week quitters remaining quitters at 1year forming the subjects of a retrospective study considering whether smoking cessation campaigns contribute significantly to radon risk reduction. Quantitative assessment of the risk of lung-cancer among the study population, from knowledge of the individuals' age, gender, and smoking habits, together with the radon levels in their homes, demonstrates that smoking cessation programmes have significant added value in reducing the incidence of lung-cancer in radon Affected Areas, and contribute a substantially greater health benefit at a lower cost than the alternative strategy of reducing radon levels in the smokers' homes, while they remain smokers. Both radon remediation and smoking cessation programmes are very cost effective in Northamptonshire, with smoking cessation being significantly more cost effective, and these are potentially valuable programmes to drive health improvements through promotion of the uptake or environmental management for radon in the home.

A staff questionnaire study of MRSA infection on ENT and general surgical wards.

Methicillin-resistant Staphyloccocus aureus (MRSA) infection has received much attention in both the medical and non-medical press. However, it is not widely encountered on ENT wards, given the profile of short-stay, relatively well patients, although its impact seems to be increasing. We wished to explore the knowledge and attitudes towards MRSA on general surgical and ENT wards, and see if there were any significant differences between specialties, or between doctors and nurses. A 13-item questionnaire with a Likert scale response with six knowledge questions and seven attitude questions was prepared. It was completed anonymously by all nursing and medical staffs on the ENT and general surgical wards of a large District General Hospital. ENT doctors displayed the lowest knowledge and attitude scores; however, this only attained significance in terms of the knowledge of the difference between infection and colonization. Overall, nurses displayed significantly more positive attitudes towards MRSA patients than doctors, but knowledge scores were not significantly different between professions. The study suggests a lack of knowledge about and preponderance of negative attitudes towards MRSA amongst ENT doctors. The difference between colonization and infection is not well understood. Reasons for this may include the relative rarity of MRSA cases on ENT wards.

Lorenz Curve and Gini coefficient: novel tools for analysing seasonal variation of environmental radon gas.

Using a methodology derived from Economics, the Lorenz Curve and Gini Coefficient are introduced as tools for investigating and quantifying seasonal variability in environmental radon gas concentration. While the Lorenz Curve presents a graphical view of the cumulative exposure during the course of the time-frame of interest, typically one year, the Gini Coefficient distils this data still further, to provide a single-parameter measure of temporal clustering. Using the assumption that domestic indoor radon concentrations show annual cyclic behaviour, generally higher in the winter months than in summer, published data on seasonal variability of domestic radon concentration levels, in various areas of the UK, Europe, Asia and North America, are analysed. The results demonstrate significantly different annual variation profiles between domestic radon concentrations in different countries and between regions within a country, highlighting the need for caution in ascribing seasonal correction factors to extended geographical areas. The underlying geography, geology and meteorology of a region have defining influences on the seasonal variability of domestic radon concentration, and some examples of potential associations between the Gini Coefficient and regional geological and geographical characteristics are proposed. Similar differences in annual variation profiles are found for soil-gas radon measured as a function of depth at a common site, and among the activity levels of certain radon progeny species, specifically (214)Bi deposited preferentially in human body-fat by decay of inhaled radon gas. Conclusions on the association between these observed measures of variation and potential underlying defining parameters are presented.

Peak flow and voice pathology.

Lung function influences voice quality. The aim of this study was to determine if there was a link between subjective voice pathology and peak flow in patients newly presenting with voice problems. A prospective, multigroup study design was designed, with three groups: New voice pathology patients presenting to voice clinics or speech therapists; General patients from ear, nose, and throat clinics with no voice or hearing abnormality; and Asthmatics presenting to general practitioner surgeries or asthma groups for review of asthma treatment. Fifty general ENT patients, 50 voice pathology patients, and 26 asthmatics were included. Peak flow and Voice Handicap Index (VHI) were measured in all subjects. Analysis of the correlation between VHI and percentage of expected peak flow showed a small correlation between the two for voice pathology patients (r=-0.304, P=0.016). No significant correlation was found for the other two groups. These results do not justify the routine measurement of peak flow in all voice clinic patients, but suggest that peak flow measurement and optimization may have a place in those with the most severely impaired VHI.

Radon remediation of a two-storey UK dwelling by active sub-slab depressurisation: effects and health implications of radon concentration distributions.

Radon concentration levels in a two-storey detached single-family dwelling in Northamptonshire, UK, were monitored continuously throughout a 5-week period during which active sub-slab depressurisation remediation measures were installed. Remediation of the property was accomplished successfully, with both the mean radon levels and the diurnal variability greatly reduced both upstairs and downstairs. Following remediation, upstairs and downstairs radon concentrations were 33% and 18% of their pre-remediation values respectively: the mean downstairs radon concentration was lower than that upstairs, with pre- and post-remediation values of the upstairs/downstairs concentration ratio, R(U/D), of 0.81 and 1.51 respectively. Cross-correlation between upstairs and downstairs radon concentration time-series indicates a time-lag of the order of 1 h or less, suggesting that diffusion of soil-derived radon from downstairs to upstairs either occurs within that time frame or forms a relatively insignificant contribution to the upstairs radon level. Cross-correlation between radon concentration time-series and the corresponding time-series for local atmospheric parameters demonstrated correlation between radon concentrations and internal/external pressure difference prior to remediation; this correlation disappears following remediation. Overall, these observations provide further evidence that radon concentration levels within a dwelling are not necessarily wholly determined by the effects of soil-gas advection, and further support the suggestion that, depending on the precise content of the building materials, upstairs radon levels, in particular, may be dominated by radon exhalation from the walls of the dwelling, especially in areas of low soil-gas radon.

A detailed evaluation of the individual health benefits arising in a domestic property following radon remediation--a case-study in Northamptonshire, U.K.

Radon gas occurs naturally in the environment with variable distribution, concentrating sufficiently in the built environment in some areas to pose a public health risk. Radon levels can be successfully reduced in affected buildings, and large-scale remediation programmes have been justified in terms of accrued costs and benefits. We present results from a house where radon levels in the main living-room and master bedroom were monitored on an hourly basis over extended periods before and after radon remediation by sub-slab depressurisation. These results were combined with results from a recent occupancy survey to estimate the health impact on occupants spending varying times in the home. Prior to remediation, mean hourly radon exposure is moderately linearly correlated (R(2)=0.66-0.78) with time spent in the house. Following remediation, correlation is significantly enhanced (R(2)=0.91-0.95), but the exposure reduction of an occupant following remediation is less than that predicted using the NRPB protocol.

Lowering the UK domestic radon Action Level to prevent more lung cancers--is it cost-effective?

Case studies have shown that radon gas can accumulate within domestic properties at sufficiently high levels that it can cause lung cancer, and recent studies have suggested that this risk remains significant below the UK domestic Action Level of 200 Bq m(-3). Raised radon levels can be reduced by engineering measures, and it has been shown that domestic radon remediation programmes in UK Affected Areas can result in reduced risks to the population and can be cost-effective. We consider here the benefits and costs of the domestic radon remediation programme in Northamptonshire, UK, and consider the implications for that programme of reducing the UK Action Level below its present value. A radon remediation programme based on an Action Level above 200 Bq m(-3) will cost less and will target those most at risk, but will be less cost-effective and will lead to higher residual dose and greater risk of cancer in the remaining population. Reducing the Action Level below 200 Bq m(-3) will prevent more cancers, but at significantly higher cost. It will also be less cost-effective, because remediation of a significant number of houses with moderate radon levels will provide only a modest health benefit to occupants. Overall, a completed radon remediation programme of the type implemented in Northamptonshire is most cost-effective for an Action Level between 200 and 300 Bq m(-3). The implications for future health policy are discussed.

Domestic radon remediation of UK dwellings by Sub-Slab Depressurisation: evidence for a baseline contribution from constructional materials.

To quantify the effectiveness of Sub-Slab Depressurisation, widely used in the United Kingdom (U.K.) to mitigate indoor radon gas levels in residential properties, a study was made of radon concentration data collected from a set of 170 homes situated in Radon Affected Areas in Northamptonshire and neighbouring counties, remediated using conventional sump/pump technology. A high incidence of satisfactory remediation outcomes was achieved, with 100% of the houses remediated demonstrating post-remediation radon concentrations below the U.K. domestic Action Level of 200 Bq m(-3), while more than 75% of the sample exhibited radon mitigation factors (defined as the ratio of radon concentrations following and prior to remediation) <0.2. Two systematic trends are identified. Firstly, absolute radon concentration reduction following remediation is directly proportional to initial radon concentration, with a mean reduction factor of 0.96 and a residual component of around 75 Bq m(-3). Secondly, houses with lower initial radon concentrations demonstrate poorer (higher) mitigation factors. These observations support a model in which the total indoor radon concentration within a dwelling can be represented by two principal components, one susceptible to mitigation by sub-slab depressurisation, the other remaining essentially unaffected. The first component can be identified with radon emanating from the subsoil and bedrock geologies, percolating through the foundations of the dwelling as a component of the soil-gas, and potentially capable of being attenuated by sub-slab depressurisation or radon-barrier remediation technologies. The second contribution can be identified with radon emanating from materials used in the construction of the dwelling with a further contribution from the natural background level, and is essentially unaffected by ground-level remediation strategies. Modelling of a multi-component radon dependency using ground-radon attenuation factors derived from the experimental data, in conjunction with typical background and structural-radon levels, yields behaviour in good agreement with the observed dependence of mitigation factor on initial radon concentration.

Health implications of radon distribution in living rooms and bedrooms in U.K. dwellings--a case study in Northamptonshire.

Environmental radon exposure of residents of domestic premises in the United Kingdom (UK) and elsewhere in Europe is estimated on the basis of the measured radon concentrations in, and the relative occupancies of, the principal living room and bedroom. While studies on radon concentration variability in the individual units in apartment blocks in various countries have been described, little data has been reported on variability in two-storey single-family dwellings, and the majority of extant studies consolidate living room and bedroom data early in the analysis. To investigate this further, detailed analysis was made of radon concentration data from a set of thirty-four homes situated in areas of Northamptonshire known to exhibit high radon levels. All homes were of typical UK construction of brick/block/stone walls under a pitched tile/slate roof. Approximately 50% of the sample were detached houses, the remainder being semi-detached (duplex) or terraced (row-house). Around 25% of the sample possessed cellars, while 12% were single-storey dwellings (bungalows), reflecting the typical incidence of this type of dwelling in England. In the two-storey homes, all monitored bedrooms were on the upper floor. Distribution of the ratios of bedroom/living room radon concentrations (BR/LR ratio) in individual properties was left-skewed (mean 0.67, median 0.73, range 0.05-1.05) with a tail extending to just above 1.0. The mean is consistent with the outcome of earlier extensive studies in England, while the variability depends principally on the characteristics of the property, and not on seasonal factors. In a small set of homes, the BR/LR ratio was anomalously low, (mean 0.3). BR/LR ratios in single-storey homes clustered around a value of 1.0, indicating that house design, rather than lifestyle, is the dominant factor in determining bedroom radon concentrations. Homes with higher mean annual radon concentrations showed lower BR/LR ratios, supporting our proposal that, in some homes, radon emanation from building materials may comprise a significant component of the overall radon level.

The value of Seasonal Correction Factors in assessing the health risk from domestic radon: a case study in Northamptonshire, UK.

Following an intensive survey of domestic radon levels in the United Kingdom (UK), the former National Radiological Protection Board (NRPB), now the Radiation Protection Division of the Health Protection Agency (HPA-RPD), established a measurement protocol and promulgated Seasonal Correction Factors applicable to the country as a whole. Radon levels in the domestic built environment are assumed to vary systematically and repeatably during the year, being generally higher in winter. The Seasonal Correction Factors therefore comprise a series of numerical multipliers, which convert a 1-month or 3-month radon concentration measurement, commencing in any month of the year, to an effective annual mean radon concentration. In a recent project undertaken to assess the utility of short-term exposures in quantifying domestic radon levels, a comparative assessment of a number of integrating detector types was undertaken, with radon levels in 34 houses on common geology monitored over a 12-month period using dose-integrating track-etch detectors exposed in pairs (one upstairs, one downstairs) at 1-month and 3-month resolution. Seasonal variability of radon concentrations departed significantly from that expected on the basis of the HPA-RPD Seasonal Correction Factor set, with year-end discontinuities at both 1-month and 3-month measurement resolutions. Following this study, monitoring with electrets was continued in four properties, with weekly radon concentration data now available for a total duration in excess of three and a half years. Analysis of this data has permitted the derivation of reliable local Seasonal Correction Factors. Overall, these are significantly lower than those recommended by HPA-RPD, but are comparable with other results from the UK and from abroad, particularly those that recognise geological diversity and are consequently prepared on a regional rather than a national basis. This finding calls into question the validity of using nationally aggregated Seasonal Correction Factors, especially for shorter exposures, and the universal applicability of these corrections is discussed in detail.

Identification of tidal and climatic influences within domestic radon time-series from Northamptonshire, UK.

Analysis of data from extended radon concentration time-series obtained from domestic and public-sector premises in the vicinity of Northampton, UK, and elsewhere, confirms that, in addition to the generally recognised climatic influences, 'Earth Tides' and 'Ocean Tidal Loading' drive periodic radon liberation via geophysically driven groundwater level variations. Regression and cross-correlation with environmental parameters showed some degree of association between radon concentration and mean temperature and rainfall. Fourier analysis of radon time-series identified periodicities of the order of 23.9 h (luni-solar diurnal, K(1)), 24.0 h (solar day, S(1)), 168 h (1 week) and 661.3 h (lunar month, M(m)), while cross-correlation with tidal strength demonstrated periodicity of the order of 14 days (lunar-solar fortnight, M(f)). These results suggest that astronomical influences, including tides, play a part in controlling radon release from the soil.

Radon mitigation in domestic properties and its health implications--a comparison between during-construction and post-construction radon reduction.

Although United Kingdom (UK) Building Regulations applicable to houses constructed since 1992 in Radon Affected Areas address the health issues arising from the presence of radon in domestic properties and specify the installation of radon-mitigation measures during construction, no legislative requirement currently exists for monitoring the effectiveness of such remediation once construction is completed and the houses are occupied. To assess the relative effectiveness of During-Construction radon reduction and Post-Construction remediation, radon concentration data from houses constructed before and after 1992 in Northamptonshire, UK, a designated Radon Affected Area, was analysed. Post-Construction remediation of 73 pre-1992 houses using conventional fan-assisted sump technology proved to be extremely effective, with radon concentrations reduced to the Action Level, or below, in all cases. Of 64 houses constructed since 1992 in a well-defined geographical area, and known to have had radon-barrier membranes installed during construction, 11% exhibited radon concentrations in excess of the Action Level. This compares with the estimated average for all houses in the same area of 17%, suggesting that, in some 60% of the houses surveyed, installation of a membrane has not resulted in reduction of mean annual radon concentrations to below the Action Level. Detailed comparison of the two data sets reveals marked differences in the degree of mitigation achieved by remediation. There is therefore an ongoing need for research to resolve definitively the issue of radon mitigation and to define truly effective anti-radon measures, readily installed in domestic properties at the time of construction. It is therefore recommended that mandatory testing be introduced for all new houses in Radon Affected Areas.

The use of the Montgomery T-tube in difficult paediatric airways.

OBJECTIVE: We report our experience of using Montgomery T-tubes in children. METHOD: A retrospective review of medical records was performed. Data collected included particular clinical circumstances, the details of usage of the tube, and the eventual outcome. RESULTS: Between January 1999 and October 2003, our unit performed 293 tracheostomies, 76 laryngotracheal reconstructions and 31 other major airway procedures in children. 10 children have had a Montgomery T-tube inserted. Nine were boys. In eight cases, the T-tube was used because of severe granulations and subsequent fibrotic narrowing in the subglottis after laryngotracheal reconstruction surgery. These children had undergone between one and four major procedures prior to T-tube placement. In the other two cases, the T-tube was used to stent severe glottic and supraglottic stenosis (due to previous laser surgery for papillomas in one case and congenital ectodermal dysplasia in the other). At the time of T-tube placement the children were aged 2-18 years (median 8 years). The tube was initially fitted so as to protrude above the glottis in all cases. In one case, the T-tube was removed on the first post-operative day. One tube was removed after a week due to severe crusting. One tube blocked after 2 weeks. One child had re-stenosis in the supraglottis necessitating the placement of a T-tube with a longer upper limb. Two children have subsequently died from non-airway causes. Two children still have their T-tube in situ, one of whom is due to have it removed in the next few weeks. Six have been successfully decannulated and are well. CONCLUSIONS: The Montgomery T-tube provides a useful adjunct to the management of a small number of children with the most difficult airway problems. Its use can be problematic, however, and requires awareness of its specific complications. We have confined usage to complex stenoses where a reconstruction would be inappropriate, or (in one instance) to stent an unsupported larynx after revision reconstruction (tracheal resection).

Time-integrating radon gas measurements in domestic premises: comparison of short-, medium- and long-term exposures.

To identify the most applicable technology for the short-term assessment of domestic radon levels, comparative assessments of a number of integrating detector types, including track-etch, electret and activated charcoal were undertaken. Thirty-four unremediated dwellings in a high-radon area were monitored using track-etch detectors exposed for one-month and three-month periods. In parallel, one-week measurements were made in the same homes at one-month intervals, using co-located track-etch, charcoal and electret detectors exposed simultaneously, while three of the homes were also monitored by continuous-sampling detectors at hourly intervals over extended periods. Calibration of dose-integrating devices against each other and against continuous-monitoring systems confirmed good responsivity and linearity. Although track-etch, charcoal and electret devices are suitable in principle for one-week measurements, zero-exposure offset and natural radon variability cause many one-week results to be equivocal, necessitating repetition of the measurement. One-week exposures can be reliable indicators in low-radon areas or for new properties, but in high-radon areas, the use of three-month exposures is indicated. This analysis also established confidence limits for short-term measurements.

Radon anomalies preceding earthquakes which occurred in the UK, in summer and autumn 2002.

During the course of an investigation into domestic radon levels in Northamptonshire, two hourly sampling real-time radon detectors were operated simultaneously in separate locations 2.25 km apart in Northampton, in the English East Midlands, for a 25-week period. This period of operation encompassed the period in September 2002 during which the Dudley earthquake (magnitude - 5.0) and smaller aftershocks occurred in the English West Midlands, UK. We report herein our observations regarding the occurrence of simultaneous short-period radon anomalies and their timing in relation to the Dudley, and other, earthquakes which occurred during the monitoring period. Analysis of the radon time-series reveals a short period when the two time-series displayed simultaneous in-phase short-term (6-9 h) radon anomalies prior to the main Dudley earthquake. Subsequent investigation revealed that a similar period occurred prior to another smaller but recorded earthquake in the English Channel.

Does a specialist voice clinic change ENT clinic diagnosis?

General ENT clinics lack the high quality diagnostic equipment and multidisciplinary advice that is available in the voice clinic. We wished to find out if referral to a specialist voice clinic from general ENT consultant clinics resulted in a change in diagnosis. Lists of voice clinic attendees were reviewed between January 2003 and May 2004. Notes were obtained for 20 patients who attended voice clinic after referral from a general ENT clinic: 3 had no diagnosis on referral to voice clinic, a diagnosis was given after attendance; 8 had their referring diagnosis changed by attendance; and 9 had no change. The voice clinic adds diagnostic value to the service available in general ENT clinics.