The aim of the study is to determine the radon concentrations in the University Hospital of Bari, Apulia Region, Southern Italy. The monitoring took place from 2017 to 2018 for a total of 402 days and included 3492 premises. Radon environmental sampling was performed with passive dosimeters of the CR-39 type. The highest mean concentration was found in basement rooms (118.9 Bq/m3), followed by ground-floor rooms (88.2 Bq/m3), first-floor rooms (78.1 Bq/m3), second-floor rooms (66.7 Bq/m3), and third-floor rooms (68.9 Bq/m3). An average radon concentration lower than the WHO recommended level of 100 Bq/m3 was detected in 73.5% of monitored environments, while only 0.9% exceeded the reference level of 300 Bq/m3 set by the national law (Legislative Decree 101/2020). The frequency of environments in which radon concentrations exceed 300 Bq/m3 is significantly higher in the basement (p-value < 0.001). As for a previous preliminary investigation in the same hospital conducted on a much smaller number of premises (n = 401), most of the monitored environments had radon concentrations lower than the reference levels set by the new national law, and the risk to the healthcare workers' health derived from occupational exposure to radon could be considered acceptable.
Keywords: healthcare workers; radon exposure; reference levels.