The monthly mean particle number concentrations varied between 580 and 2100 particles cm− 3 at Arctowski, between 90 and 1270 particles cm− 3 in Hornsund, and between 6700 and 14,000 particles cm− 3 in the middle latitude station Swider. Average diurnal variations of the ground-level electric field Ez and particle number concentrations in fair-weather conditions were independent of each other for Arctowski and Hornsund stations. At Swider station the diurnal variation is usually characterized by an increase of aerosol concentration in the evening which results in the increased electric field. The assumption of neglecting the influence of varying aerosol concentration on the variation of the electric field in the polar regions, often adopted in studies, is confirmed here by the observations at Arctowski and Hornsund.
The results of aerosol observations are also compared with modelled aerosol concentrations for global atmospheric electric circuit models.