An experimental technique, including the differential mobility analyzer and laser aerosol spectrometer, is proposed for determining the aerosol particles charge distribution, charged by the corona discharge. Experimental data processing procedure for determining the polydisperse welding fume particles charge distribution is proposed. Unipolar particle charging process in the environment saturated by ions is studied. Proposed theoretical model of unipolar charging in approximation of the dust-ion plasma demonstrates good correlation with experimental data. The two-dimensional size and charge distributions of welding fume particles are demonstrated. (C) 2015 Elsevier Ltd. All rights reserved.