For this reason, we felt the requirement to deepen our understanding on the radon present in the Etnean area, focusing in specific on indoor radon pollution that, as extensively acknowledged, is amongst the main causes of cancer mostly (however not solely) of the respiratory system. Radon is extensive in the Earth’s crust, with activity concentrations varying many orders of magnitude, primarily depending on the initial uranium content, on the physical characteristics of the rocks and on the ways of its movement through the rocks and soils. High activity concentration in radon emissions at the topographic surface area is produced by convective flow of gases that facilitate the transportation of radon from greater depth within soils.

Faults and fractures of the Earth’s crust are the simplest courses for radon to move through the rocks and get to the surface since these zones are generally defined by a greater porosity than surrounding rocks. Indeed, faults are likely the places of high soil degassing and raised radon activities (3– 7).

In recent years, lots of in-soil radon measurements were undertaken on Mt. Etna volcano (Italy), one of the most active volcanoes in the world (8) (Figure 1). While showing extremely helpful for keeping an eye on faults and volcanic activity, radon emissions can be seriously detrimental to human health. Constant exposure to high concentrations of radon in inadequately aerated areas such as houses and offices positions radiation danger for those individuals inhaling radon gas.

Given the potential risk due to radon direct exposure, the strong radon emissions from the soils of the Etna location determined thanks to the current examinations have led the local scientific neighborhood to start undertaking research studies on the build-up of this gas inside houses and public structures in metropolitan areas built in the neighboring location. Though limitations on indoor radon exposure have actually been already set in numerous countries( 30), in numerous largely inhabited volcanic areas, and especially on Etna, systematic measurements of indoor radon concentrations had never ever been brought out so far and for that reason the threat postured by radon was almost unknown. For the above reasons, in this paper we present the very first ever long-lasting tracking of indoor radon on Mt. Etna.

We compared the obtained data on radon activity with the geological settings at each website, in order to recognize all possible sources of radon. In some cases, we discovered levels of radon activity potentially harmful for the local residents. The monitor computes and tape-records both the everyday and the weekly typical radon activity and it supplies the cumulative radon activity concentration in the long term, up to 1 year.

We selected 7 areas at various elevations (from 42 to 592 m above water level) on the eastern and southern slopes of Mt. Etna, selected in places where high radon activity concentration had been measured in soils throughout previous surveys (10, 12, 13, 34). In three of those areas, we utilized numerous active radon monitors together throughout the period of our examination, to evaluate possible concurrent temporal variations of radon activity in various spaces. Houses and school structures were picked likewise based on the residents’ willingness to collaborate willingly with data collection.

Modifications in radon activity had to be transcribed to a spreadsheet by the operator day by day, considering that the instruments completely kept only the average worth of radon activity (in the long– term mode). The school-age young persons, before being included as operators, were preliminarily advised with seminars on radon gas and its potential effects, both positive (as tracer of geodynamic activities) and unfavorable (as a danger element for lung cancer).

Twelve Canary digital radon-monitors were utilized at the 7 areas above, with measurements taken throughout different intervals from 11/12/2015 till 20/10/2018. In a few of the 7 locations, more instruments were put in order to monitor various rooms (Table 1). All spaces were without a basement underneath.