Abstract Radon gas concentration and other environmental parameters are continuously measured in several popular tourist caves and galleries in Slovakia. The primary objective of this survey is to monitor radon seasonal variations and better understand cave internal processes. Based on this knowledge, the estimation of doses for tourist guides will be more efficient and closer to actual values. In the most popular caves in Slovakia, the number of visitors can reach over 100,000 per year. Including preparatory and maintenance work, the employees spend several hours per day inside the caves, which increases the potential to accrue ionizing radiation dose exceeding the annual effective dose limit of 20 mSv. Currently, four caves—Bystrianska Cave, Belianska Cave, Malá Stanišovská Cave, and Driny Cave—and two galleries—Bear Gallery and Salvátor Gallery—are periodically monitored using solid-state alpha-track detectors in combination with continual radon detectors. In total, 34 positions of the guided tour paths are monitored by 102 detectors. The solid-state alpha-track detectors are evaluated at one-month and three-month intervals to obtain seasonal variation. This paper summarizes applied methodology and the preliminary results from the first period of the monitoring for three selected caves, where the radon-specific activity varies from several hundreds of Bq/m 3 to several thousands of Bq/m 3 depending on location and season period.
Lüley et al. (Mon,) studied this question.