The operational sustainability of radiative cooling technologies is critically dependent on understanding their performance degradation under environmental fouling. This study establishes a comprehensive computational framework to investigate the coupled heat transfer phenomena governing this degradation, with a specific focus on the chemical composition of deposited atmospheric dust. A Monte Carlo Ray Tracing (MCRT) model, rigorously validated against experimental data, is developed to resolve the complex energy balance involving volumetric shortwave absorption/scattering within the dust layer, surface longwave emission, and convective heat exchange. Our computational results reveal a crucial dichotomy in the degradation mechanism: while benign mineral components (SiO₂, Al₂O₃) induce a linear and moderate performance decline, high-absorption constituents, notably Carbon and Fe₂O₃, trigger a catastrophic, exponential loss of function even at trace concentrations. This work provides a new level of physical insight and delivers a robust predictive tool for a challenging computational heat transfer problem.

Radiative cooling,MCRT,radiation transfer