Formation of ions under the action of cosmic rays in humid air

The processes of ion formation in humid tropospheric air under the action of cosmic rays are considered. In this case, positive and negative cluster ions appear. For this analysis, a kinetic model was developed that includes 55 components and 161 reactions. The calculation was carried out using the KINET software package. It is shown that the ionization of air by cosmic rays at altitudes of 5–35 km leads to the formation of plasma consisting mainly of NH4+⋅NH3⋅H2O, H+⋅(H2O)4 and O2−⋅(H2O)2 ions. The maximum concentrations of ions under conditions of minimum magnetic rigidity are observed at altitudes from 10 to 18 km. These results differ sharply from the calculation results obtained for the dry air model. •The ionization of air by cosmic rays leads to the formation of positive and negative cluster ions in low atmosphere.•The protonated ions containing NH3 groups appear at altitudes below 15 km.•The hydrated hydronium ions are preferably formed at altitudes above 15 km.•The hydrated oxygen anion clusters are the most numerous in the low atmosphere.