Enhanced effect of water vapor on complete oxidation of formaldehyde in air with ozone over MnOx catalysts at room temperature

► Enhanced effect of H2O on OZCO of HCHO to CO2 and reaction stability is reported. ► The carbonates formed on catalysts increased gradually with TOS in the dry stream. ► Almost no accumulation of carbonates on catalysts was observed in the humid stream. ► Reaction pathways are proposed for OZCO of HCHO in dry and humid air streams.