2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/2916The emission-line flux ratio of [O III]4363/[O III]5007 is a useful diagnostic for the ionization mechanism and physical properties of narrow-line regions in active galactic nuclei. However, it is known that simple photoionization models underpredict this ratio. In this contribution, we report on some pieces of evidence that a large fraction of the [O III]4363 emission arises from the dense gas, which can be obscured by dusty tori. Taking this dense component into account, we show that the flux ratio of [O III]4363/[O III]5007 can be explained by two-component photoionization models.4 pages. To be published in The Central kpc of Starbursts and AGNs, ASP Conference Series, eds. J. H. Knapen, J. E. Beckman, I. Shlosman, and T. J. MahoneyAstrophysicstext