During the first 3 min under light, HPs produce a significant number of electrons that are trapped by BMPO (Figure ). The EPR spectra of HPs in both solutions exhibit typical BMPO/•OH or BMPO/•OOH signals under illumination conditions. As the illumination time increases, we observe a reduction and change in the EPR signal, indicating the formation of unconventional Br, Cs, and Pb-related adducts due to the decomposition of HPs (Figures , Tables ).