G. Taino et al.: Radioprotection 2025, 60( 1), 76 – 83 77
100 Bq / m 3 and doubles at 600 Bq / m 3. The overwhelming majority of Italian population is exposed to average mean Radon concentration below 100 Bq / m 3, 4 % is exposed to an average mean concentration higher than 200 Bq / m 3 and 1 % to concentration above 400 Bq / m 3( Darby S et al., 2005).
According to the Italian Higher Institute of Health( Istituto Superiore di Sanità, ISS), among the 31000 yearly cases of lung cancer, between 1000 and 5500 may be attributed to exposure to Radon, especially among smokers( Epicentro, ISS).
Requirements for exposure to Radon in the workplace are governed by Italian Legislative Decree 101 / 2020, transposition of Directive 59 / 2013 / Euratom in accordance with the recommendations of The International commission on radiological protection( ICRP) 103( ICRP, 2007) This legal framework identifies the“ reference level” as an operational tool for radiation protection. This, for the Radon, is defined as the concentration of activity in the air, to be considered as a value above which it is not appropriate for exposure to occur. However, it is not an“ hard limit” and protective interventions must also be adopted below this level; therefore, it is no longer to be understood as a“ threshold”. This reference level understood as the average annual concentration of Radon is set at 300 Bq / m 3( EU Directive 59 / 2013 / Euratom and Legislative Decree 101 / 2020) in the living and working places. For houses built after 31 / 12 / 2024 a lower limit will be applied, equal to 200 Bq / m 3.
The first assessment of the average annual concentration of Radon activity at the workplace must be carried out within 24 months from the start of the activity or from the definition of the areas at risk or from the identification of specific types in the National Plan. The employer must also assess the risk of exposure to Radon in cases where there are workers who remain in underground or semi-underground environments( at least three walls bordering the ground) for at least 10 hours a month. The rules relating to protection from Radon in the workplace apply to work activities carried out in underground environments, in spas, in basement workplaces and on the ground floor if located in priority areas( Italian Law, D. L. 101 / 2020). The document that is drawn up following the assessment is an integral part of the Risk Assessment Document( Italian Law, D. L. 81 / 2008). The timing of the measures is defined in advance: every time structural interventions are made at the level of ground connection, or thermal insulation; every 8 years, if the concentration value is less than 300 Bq / m 3.
If the reference level of 300 Bq / m 3 is exceeded, corrective measures must be taken within two years to lower the level below the reference value. The effectiveness of the measures is evaluated through a new assessment of the concentration. In particular: following a positive result( less than 300 Bq / m 3, which means a good result as the Radon levels found are sufficiently low) the measurements are repeated every 4 years; if the concentration is still higher, it is necessary to evaluate the annual effective doses through a radiation protection expert who issues a specific report. The " reference level " in this case is 6 mSv per year, according to the conversion factor for Radon updated according to the ICRP137 recommendation( ICRP, 2017).
If the result of the assessments is lower than the maximum reference levels, the employer must keep the effective doses or exposures of workers under control; furthermore, they are required to keep the results of the evaluations for at least 10 years.
If the results of the assessments are instead higher than the maximum reference limits, the employer must adopt the measures provided for by title XI of Legislative Decree 101 / 20, in particular appointing the“ Medico Autorizzato”( according to Italian law, a physician especially trained in the matter of radioprotection and registered to the Ministry of Labour after passing the required examination; such figure is the only allowed to carry out medical surveillance of the exposed to ionizing radiation) for health surveillance( as indicated by the Directorate-General Environment, Nuclear Safety and Civil Protection of the European Commission, Radiation Protection 112, 1999).
2 Overview of risks factors and health surveillance
The health surveillance of workers exposed to Radon is aimed at the prevention and early diagnosis of lung cancer.
In fact, the 5-year survival of lung cancer patients in Italy is 16 %, while the 10-year survival is 12 %, negatively affected by the large proportion of patients diagnosed at an advanced stage. Diagnosis of lung cancer at an early stage offers the real possibility of reducing mortality through new treatments.
3 Identification of factors associated with the development of lung cancer
The main risk factor for lung cancer is cigarette smoking, which accounts for 85 – 90 % of all cases. The relative risk increases about 14 times in smokers and up to 20 times in heavy smokers( Crispo et al., 2004; Alberg et al., 2005).
Several studies show that passive smokers have an increased risk of developing lung cancer between 20 and 50 % compared to non-smokers( Zhong et al., 2000; Taylor et al., 2007).
Environmental factors, such as exposure to atmospheric particulate matter and pollution, has been classified by the IARC as a human carcinogen. An increased risk of lung cancer in association with increased concentrations of fine particles was identified in the AHSMOG-2 study( Gharibvand et al., 2017).
In the ESCAPE study a 55 % increase in the risk of developing lung adenocarcinoma by fine particles( Particulate matter air pollution) was found( Raaschou-Nielsen et al., 2013).
Among lung cancer’ s risk factors there is occupational exposure to toxic substances, such as Radon and asbestos, and heavy metals( chromium, cadmium, arsenic, etc.).
The marginal role of genetic predisposition has been highlighted in recent years, especially as regards genetic polymorphisms( Yokota et al., 2010).
Among lung cancer’ s risk factors: chronic inflammatory processes, such as tuberculosis.
While tobacco smoke is the main risk factor for lung cancer, exposure to Radon is the first cause in non-smokers, and retains the second place in smokers where it is shown to