Background: Indoor radon exposure is the second leading cause of lung cancer. Finnish radiation legislation obligates employers to measure indoor radon concentrations in workplaces, including schools and daycare centers, if they are in radon prone areas. Surveillance campaigns were conducted to ensure that the required radon measurements were performed and to gain knowledge on current indoor radon levels in daycare centers and schools. Methods: Daycare centers located in the high-radon risk municipalities were identified. Schools where indoor radon level measurements were obligatory but not performed, were identified. Results: Indoor radon measurements were performed in 633 daycare centers where the mean radon concentration was 86 Bq/m³ and the median 40 Bq/m³. The radon level was greater than 300 Bq/m³ in 8% (n = 49) of daycare centers. The radon measurements were performed in 1176 schools, which is 95% of the schools to be measured. The mean radon concentration was 82 Bq/m³ and the median 41 Bq/m³. The radon levels were greater than 300 Bq/m³ in 14% (n = 169) of the schools. Conclusions: The systematic surveillance campaigns by the radiation protection authority were very efficient in order to ensure that the measurements are performed in schools and daycare centers. The campaigns also reduced the radon exposure of employees, children, and adolescents, where necessary.

Increased incidence of skin cancers among airline cabin crew has been reported in several studies. We evaluated whether the difference in risk factor prevalence between Finnish airline cabin crew and the general population could explain the increased incidence of skin cancers among cabin crew, and the possible contribution of estimated occupational cosmic radiation exposure. A self-administered questionnaire survey on occupational, host, and ultraviolet radiation exposure factors was conducted among female cabin crew members and females presenting the general population. The impact of occupational cosmic radiation dose was estimated in a separate nested case–control analysis among the participating cabin crew (with 9 melanoma and 35 basal cell carcinoma cases). No considerable difference in the prevalence of risk factors of skin cancer was found between the cabin crew (N = 702) and the general population subjects (N = 1007) participating the study. The mean risk score based on all the conventional skin cancer risk factors was 1.43 for cabin crew and 1.44 for general population (P = 0.24). Among the cabin crew, the estimated cumulative cosmic radiation dose was not related to the increased skin cancer risk [adjusted odds ratio (OR) = 0.75, 95% confidence interval (CI): 0.57–1.00]. The highest plausible risk of skin cancer for estimated cosmic radiation dose was estimated as 9% per 10 mSv. The skin cancer cases had higher host characteristics scores than the non-cases among cabin crew (adjusted OR = 1.43, 95% CI: 1.01–2.04). Our results indicate no difference between the female cabin crew and the general female population in the prevalence of factors generally associated with incidence of skin cancer. Exposure to cosmic radiation did not explain the excess of skin cancer among the studied cabin crew in this study.

The aim of this study was to obtain information on the radon concentrations to which Finnish workers are exposed. Radon measurements were conducted as integrated measurements in 700 workplaces, supplemented by continuous radon measurements in 334 workplaces. The occupational radon concentration was calculated by multiplying the result of the integrated measurements by the seasonal correction factor and the ventilation correction factor (ratio between the working time and the full-time radon concentration obtained from continuous measurement). The annual radon concentration to which workers are exposed was weighted by the actual number of workers in each province. In addition, workers were divided into three main occupational categories (working mainly outdoors, underground, or indoors above ground). Probability distribution of the parameters affecting radon concentration levels were generated to calculate a probabilistic estimate of the number of workers exposed to excessive radon levels. With deterministic methods, the geometric and arithmetic mean radon concentrations in conventional, above-ground workplaces were 41 and 91 Bq m⁻³, respectively. The estimated geometric and arithmetic mean annual radon concentrations that Finnish workers are exposed to were assessed as 19 and 33 Bq m⁻³, respectively. The generic ventilation correction factor for workplaces was calculated as 0.87. Assessed with probabilistic methods, there are approximately 34,000 workers in Finland whose exposure to radon exceeds the reference level of 300 Bq m⁻³. Although radon concentrations are generally low in Finnish workplaces, many workers are exposed to high levels of radon. Radon exposure in the workplace is the most common source of occupational radiation exposure in Finland.

(1) Background: Affordable electronic radon instruments have become increasingly popular as alternatives to traditional home radon measurements, which require a minimum duration of two months. This study aimed to determine how results obtained from these devices should be interpreted and whether short-term measurements lasting 2–5 days can be reliably used to assess the need for radon remediation in buildings, estimate residents’ exposure, or assess public exposure. (2) Methods: A year-long radon measurement was conducted in 55 dwellings, selected to represent the Finnish housing stock as accurately as possible. Radon concentrations were recorded hourly, and the results were analysed using probabilistic analysis to calculate the likelihood of erroneous assessments. (3) Results: If a maximum false-negative rate of 1% is accepted, the action level for a 2–5-day measurement is 90–100 Bq/m³. For measurements exceeding this threshold, a longer measurement period is necessary. (4) Conclusions: Based on this study, short-term radon measurements cannot yet be recommended as a replacement for current methods. However, the study revealed significant radon level fluctuations in September, suggesting that this period should be reconsidered for inclusion in the measurement season.

Radon measurements in Finnish underground mines were started in 1972. Since 1992, regular radon inspections by the competent authority have been carried out in all underground mines. During these inspections, several grab samples are taken from the air, which are later measured in the laboratory. This is a follow-up survey of radon concentrations in the air of the underground mines. The average radon concentrations in the mines between the years 2011 and 2019 varied from 90 to 1100 Bq m ⁻³ . Overall, the occupational radon exposure in the Finnish underground mines has remained at a low level from the 1990s onwards. In recent years, high radon concentrations have been observed only in those mines where active mining has ceased. Compared to other recent studies in mines in other countries, radon concentrations in Finnish mines are approximately at the same level. Uncertainties relating to infrequent grab sampling have been recognised and the authority is now testing personal radon detectors that may be used for the exposure assessment in the future.

The Cohort Study of Mobile Phone Use and Health (COSMOS) has repeatedly collected self-reported and operator-recorded data on mobile phone use. Assessing health effects using self-reported information is prone to measurement error, but operator data were available prospectively for only part of the study population and did not cover past mobile phone use. To optimize the available data and reduce bias, we evaluated different statistical approaches for constructing mobile phone exposure histories within COSMOS. We evaluated and compared the performance of 4 regression calibration (RC) methods (simple, direct, inverse, and generalized additive model for location, shape, and scale), complete-case analysis, and multiple imputation in a simulation study with a binary health outcome. We used self-reported and operator-recorded mobile phone call data collected at baseline (2007-2012) from participants in Denmark, Finland, the Netherlands, Sweden, and the United Kingdom. Parameter estimates obtained using simple, direct, and inverse RC methods were associated with less bias and lower mean squared error than those obtained with complete-case analysis or multiple imputation. We showed that RC methods resulted in more accurate estimation of the relationship between mobile phone use and health outcomes by combining self-reported data with objective operator-recorded data available for a subset of participants.