Quantum gravity may allow black holes to decay into white holes. If so, the lifetime of a black hole would be shorter than the one given by Hawking evaporation, avoiding the information paradox. This could open to a new window for quantum-gravity phenomenology, in connection with the existence of primordial black holes. I discuss the possibility to observe an astrophysical emission from the explosion of primordial black hole in the radio and in the gamma wavelengths. Those emissions can be discriminated from other astrophysical sources because of the peculiar way the emitted wavelength scales with the distance. In particular, the spectrum of the diffuse radiation produced by those objects presents a distortion due to this scaling. Finally, primordial black holes decaying into white holes are dark matter candidates, whose peculiar features should be studied in cosmology.