<p>Rotating porous sandwich plates are increasingly deployed as load-bearing filtration elements, where continuous pollutant deposition can gradually reshape both inertia and stiffness and, in turn, the vibration signature used for safe operation and condition monitoring. In this work, the free vibration of a three-layered rotating annular sandwich plate with a porous core is investigated in a pollutant-laden environment through a coupled mass–stiffness modification framework. A refined zigzag kinematic description is adopted to capture realistic transverse shear and layerwise slope discontinuities with a compact set of generalized variables, while centrifugal pre-stress is consistently incorporated in the energy formulation. Pollutant accumulation is represented by an equivalent surface mass per unit area and a stiffness modification coefficient that predominantly affects the porous core through pore infiltration and interaction, and both effects are embedded into the inertia terms, stiffness resultants, and rotational pre-stress contributions. The resulting governing equations are solved numerically using the generalized differential quadrature method. The results reveal that the frequency sensitivity to stiffness modification is strongly governed by the core thickness ratio, indicating a geometry controlled environmental sensitivity, while centrifugal stiffening at higher rotational speeds can partially mask the influence of the core architecture. Moreover, the combined action of deposited mass and stiffness modification is shown to be non-additive, which suggests that vibration-based diagnostics should account for coupled contamination mechanisms in rotating filtration structures.</p>