Concentration and Mobility of Air Ions in the Environment of the Cisarska Cave (Moravia)

In this paper, the authors deal with the sensing and evaluation of signals obtained in the field of low-level electric charge measurements. The measurement took place in the Cisarska cave (Moravia) under specific temperature and humidity conditions for a long time. Compared to conventional techniques, the proposed method shows a lower standard deviation and analyzes the causes of spurious oscillations. The sensing method was based on measurement by a capacitive sensing sensor with controlled passage of negative ion carriers. Long-term changes in negative ion concentration are evaluated. The limestone walls, which have very beneficial material properties in terms of permittivity and electrical conductivity, are also important for the evaluation of the cave space. The maintenance of a clean limestone surface is important in terms of preserving the healing properties of the cave; the surface of the limestone has been tested in detail in terms of ions. The maintenance of a clean limestone surface is important in terms of preserving the healing properties of the cave; the surface of the limestone has been tested in detail in terms of ions. Low measurement uncertainties are necessary for the correct determination of the saturation characteristics. From this, the mobility spectrum of air ions is calculated. The obtained results of the recalculation from the saturation characteristics show the surprising origin of air ions in the cave, where the only source may not be radioactive radon, but the contribution of splintering water droplets is also significant. These results could not have been obtained without the proposed measurement methodology.