Graphic of the proposed scenario of sublimation in a disk with a warm dust trap, viewed from the side, based on van der Marel et al. (2021b). If the bulk of the dust content is located in a dust trap inside the CO snowline at 30 K, this implies that fragments of its icy pebbles can be transported vertically to the higher disk layers above the H₂O snow surface at 150 K, and sublimate their icy content into the gasphase, where it becomes observable. If the bulk of the pebbles is located outside the CO snowline, its icy layers may remain frozen out and its contents are not revealed in the gas phase. Such a scenario may also apply to PAHs, which is the hypothesis of this work.