In this paper, new long-term measurements of chemical composition and physical properties of atmospheric aerosols carried out on the eastern brink of the heavily polluted Highveld area in South Africa are introduced. As expected, a high variability of aerosol properties was observed. Optical properties of aerosol particles were found to be closely correlated with particulate mass and number concentration in the case of polluted air masses. In contrast, in clean conditions there was no clear connection between optical properties and aerosol number concentration due to the presence of multiple sources including new particle formation.