In the framework of the UR. 2 of the project DPC-INGV S3 “Short term earthquake prediction and preparation“ (Albarello, 2013), a database, containing radon data collected and provided by scientific institutions or volunteers, accompanied, when available, by meteorological data recorded by the radon instruments, or from meteorological stations located near the site of detection of radon, was created. The database has 3,961 sites and more than one million records (Martinelli et al., 2013; Riggio et al., 2013). The collected data are related to radon acquired in the air, soil and water, for different purposes (health, environmental, seismological). Consequently, also the types of instruments are different and can be used in active or passive mode, in the first case recording the amount of radon present in the environment, and in the second one aspiring radon through an incorporated pump. They consist of commercially available monitors, monitor prototypes from scientific institutions or amateurs, or by commercially available dosimeters. Another important information to evaluate the data, reported in the database, is given by the characteristics of the site, that is, if the instrument is located in a well, in a basement, in homes, or on the ground, with a probe that aspires in the soil. The sampling time is between ten minutes and twelve hours for the measures considered continuous, and between fifteen days and one year for the discretized ones.
