Nitrate aerosols play an important role in affecting regional air quality as well as the Earth’s climate. The photolysis of particulate nitrate is an important sink of nitrate aerosol, which is not considered in most global climate models (GCMs) and has large uncertainties. We recently implemented the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) module in the U.S. DOE Energy Exascale Earth System Model version 2 (E3SMv2), which was integrated with the Model for Ozone and Related chemical Tracers (MOZART) gas chemistry and the four-mode version of Modal Aerosol Module (MAM4) to simulate nitrate aerosols and their radiative effects. In this study, we implement the particulate nitrate photolysis as well as the related HONO chemical reactions in MOZART to investigate their impact on the lifecycle of nitrate aerosol and gas species and the radiative forcing of nitrate. We conduct sensitivity experiments with perturbations to the photolysis rate constant of particulate nitrate (j_pNO3 ) that is calculated by scaling the photolysis frequency of HNO₃ (j_HNO3) by an enhancement factor (EF). Laboratory studies suggested that EF can range from 1 to 1000. We evaluate simulated nitrate aerosol as well as gas species (e.g., O_3, NO_x, HNO₃, and HONO) in E3SMv2 against ground-based networks (e.g., CASTNET, EMEP, and EANET), aircraft campaigns (e.g., ATom), and satellite retrievals. We find that particulate nitrate photolysis can significantly reduce the global annual mean nitrate burden by 11% and 34% with EF of 10 and 100, respectively, while slightly increase the global tropospheric HNO₃ burden. The photolysis slightly increases nitrate surface concentrations but considerably decreases nitrate concentrations in the middle to upper troposphere. We also quantify the resulted changes in radiative forcing of nitrate.