The ethanol sensitivity-temperature curves of SmCoO3/ZnO, In2O3 have two peaks under dry air. The ethanol sensitivity of SmCoO3/MOx, except for SmCoO3/Fe2O3, extremely decreased in wet air. For SmCoO3/ZnO, the sensitivity peak at around 623 K decreased with increasing humidity. For SmCoO3/Fe2O3, the sensitivity peak at 373 K disappeared and a new peak appeared at around 773 K in wet air. For SmCoO3/SnO2, the sensitivity decreased with increasing humidity. For SmCoO3/In2O3, the sensitivity disappeared in wet air. (C) 3000 Elsevier Science S.A. All rights reserved.