A system for air purification based on in-situ photocatalytic oxidation and ozonation includes a single multi-functional Ti02-based coating having photocatalytic activity for oxidation in the presence of a sufficient ozone supply and UV irradiation to synergistically oxidize gaseous pollutants at ambient conditions. Also disclosed is a method for removing gaseous pollutants using ozone and UV irradiation to simultaneously activate the photocatalytic oxidation in the presence of the Ti02-based coating to remove up to about 84% of the gaseous pollutants within 5 minutes.