In order to simulate the atmospheric corrosion of steel, artificial steel rust particles were synthesized by aerial oxidation of aqueous solutions containing FeCl2, FeSO4 and NaNO3, and the structure and morphology of the obtained particles were characterized by XRD and TEM. Needle-like SO42- containing Schwertmannite (Fe8O8(OH)(6)(SO4)) particles were mainly formed in FeCl2-FeSO4, FeSO4-NaNO3, FeCl2-FeSO4-NaNO3 systems, and the crystallization and particle growth of this material were not influenced by added Cl- and NO3-. The rod-shaped beta-FeOOH particles were formed from in only FeCl3-NaNO3 system, though no marked change in crystallite and particle sizes of the beta-FeOOH was recognized by adding NO3-. Accordingly, it can be suggested that the corrosive SOx gas and air-borne chloride strongly affect the rust formation in atmospheric corrosion of the steels. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan.