Gas response control through structural and defect engineering in metal oxides are critical approaches to realize high performance sensors. Herein, we present the fabrication of ZnO thin films containing nanosized structures and high concentration of zinc interstitials for NO2 and ethanol monitoring. The target materials were fabricated by aerosol assisted chemical vapour deposition (AACVD) method on ceramic and glass substrates, and were characterized by complementary analytical techniques. The obtained ZnO nanoparticulate and nanopyramidal thin films yielded an outstanding response of similar to 41 to 1 ppm NO2 and similar to 236 towards 100 ppm ethanol, respectively. The reasons accounting for such an enhancement were revealed by the surface-depletion model in ZnO and the chemisorption energies of oxygen molecules on Zn-i-enriched crystal facets.