Uncertainty on long-term average radon concentration has a large impact on lung cancer risk assessment in epidemiological studies. The uncertainty can be estimated by year-to-year radon concentration variability, however few data are available. In Italy a study has been planned and conducted to evaluate year-to-year radon variability over several years in normally inhabited dwellings, mainly located in Rome. This is the longest study of this kind in Europe; repeat radon measurements are carried out for 10 years using LR-115 radon detectors in the same home in consecutive years. The study includes 84 dwellings with long-term average radon concentration ranging from 28 to 636 Bq/m3. The result shows that year-to-year variability of repeated measurements made in the same home in different years is low, with an overall coefficient of variation of 17%. This is smaller than most of those observed in studies from other European countries and USA, ranging from 15% to 62%. Influencing factors that may explain the differences between this study and other studies have been discussed. Due to the low yearly variability estimated in the present 10-year study, a negligible impact on lung cancer risk estimate for the Italian epidemiological study is expected.

The performance of continuous radon monitors (CRMs) is usually evaluated under controlled conditions in a radon chamber during calibrations or intercomparison exercises. The impact of thoron on CRMs response is rarely evaluated; in case the evaluation is performed, it is carried out in a controlled atmosphere with relatively constant, homogeneous, and generally high thoron concentrations and very low radon levels. In a real indoor environment, both radon and thoron concentrations are extremely variable, so the thoron interference evaluations reported in the literature are generally not applicable to CRMs used to measure radon concentration indoors. For this reason, an experimental study was carried out with four different CRMs in an indoor environment (an office room) where medium-to-high concentrations of both radon and thoron were expected. Thoron concentration has been separately evaluated throughout two different active monitors. Three CRMs resulted in overestimations of radon concentration by about 10% due to thoron interference, whereas such interference results were negligible for the fourth CRM. However, the thoron interference can also be used to assess thoron concentration by using CRM not specifically designed to do so. Based on the results of this study, an indirect method to assess thoron concentration is indeed proposed, relying on the combination of two identical monitors (one placed right close to the wall and the other one far enough from there).

The European Medicines Agency (EMA) has adopted assessment systems and drug registration procedures to respond to the needs for rapid patient access to therapies, such as Conditional Marketing Approval (CMA) and Under Exceptional Circumstances approval (UEC). The Italian Medicine Agency (AIFA) has introduced tools for governing prescriptive behaviour in order to promote appropriateness and correct use of drugs and to manage the uncertainty of financial impact, including Managed Entry Agreements (MEAs). The MEAs are conditional access agreements to the market for new drugs aimed at managing the uncertainty on the clinical and economic effects of the drugs themselves. The aim of this study is to analyse, through the use of the information systems of the AIFA and the institutional website of the EMA, how the drugs authorised by EMA with CMA or UEC have been managed on the access side to the Italian NHS. This in order to understand how the uncertainty deriving from the authorisation processes was subsequently reflected on the reimbursement processes to be borne by the NHS. From the analyses carried out, it emerges that 64% of the drugs approved with CMA were admitted to reimbursement and 68% of those approved with the UEC procedure. Furthermore, it can be noted that approval with CMA is predictive for the application of a financial-based or outcome-based MEA (61%), with the application of a monitoring register, unlike the drugs approved UEC for which no conditional reimbursement arrangements have been applied at the patient level. Furthermore, by carrying out a comparative analysis of the time of access to market following negotiation, from the positive opinion of the CHMP to the decision published in the Official Gazette of the Italian Republic, it emerged that the drugs approved by the UEC procedure take on average more time (897 days) to arrive at the price and reimbursement (P&R) compared to CMA drugs (636 days). Considering instead only the period from the request for P&R to the determination of P&R for the same group of drugs, the process seems to be on average faster for the drugs classified as UEC than for those with CMA (329 vs. 510 days).

National surveys on radon concentration in dwellings that are representative of population exposure are recommended by international regulations but are often difficult and costly to carry out. Furthermore, evaluation of sample representativeness is usually not reported, making it impossible to quantify or correct potential biases. This study aimed to develop and test, in a real-world setting, methods to plan and implement a cost-effective national survey on radon concentration in dwellings that includes a large proportion of municipalities, allows for the assessment of representativeness, and enables bias correction when the sample is not fully representative. A comprehensive national survey was conducted efficiently and at low cost in collaboration with a national company with numerous worksites. The company provided: i) a list of all employee dwelling addresses, enabling random selection across all 110 Italian provinces; ii) internal email and web platforms, for communication with workers and completion of questionnaire data, iii) internal mail service, for distributing and retrieving radon detectors which were centrally prepared and read out. Moreover, questionnaire data on dwelling characteristics were collected and compared with census data to assess representativeness and adjust for potential biases. Valid radon measurements were obtained for 5354 dwellings. After correcting for two major identified biases, the national Italian arithmetic mean was 79 Bq/m³ with values ranging from 34 to 132 Bq/m³ across the 21 Regions and from 25 to 343 Bq/m³ across the 110 Provinces. Without corrections, the national mean would have been underestimated by about 10 %, regional means by up to 30 %, and even more at the provincial level. The results demonstrate that a national survey can be conducted effectively and affordably, using methods that can be adopted by other countries. Furthermore, the study highlights the importance of assessing representativeness to avoid significant biases.

Radon concentration data originating from different surveys can be combined for several purposes: epidemiological analyses, aimed at estimating radon‐related health risks; mapping applications, intended to identify radon‐prone areas; but also for population exposure assessment, by making optimal use of the information contained in the different datasets. Although individual surveys often have limited sample sizes, the increasing availability of survey radon data since the 1980s offers an opportunity to improve knowledge of radon distribution. However, this requires a robust methodology capable of comparing surveys with differing designs and objectives, and of appropriately combining their results while accounting for the specific objectives of the data combination. This paper specifically tackles the inherent challenge of comparing and subsequently combining such heterogeneous datasets in order to achieve a more comprehensive and robust assessment of population radon exposure. To this end, a step‐by‐step procedure designed to facilitate the combination of data from various radon surveys is proposed. A practical application of this methodology has been carried out for the city of Rome, Italy, where data originating from five distinct surveys, carried out since approximately 1990, have been compiled, compared, and (four of them) combined to obtain a better evaluation of the exposure of the population of Rome and its 12 administrative units ( municipi ). As a key outcome of this application, the study will produce a radon “expected burden” map for the different municipi (administrative divisions) of the city of Rome. This map will account for both the estimated radon concentration within each municipio —derived from the combined analysis of the diverse survey data—and the corresponding population size, thereby providing a population‐weighted spatial assessment of radon exposure in the general population, crucial for evaluating health impacts and guiding mitigation strategies.