The Self‑Powered Purifying Rotor — A Wheel‑Integrated System for Active Capture of Non‑Exhaust Emissions via Motion‑Harvested Electrostatic Filtration and Radiative Cooling (Concept v1.0)

We outline a wheel‑integrated Purifying Rotor that couples passive, rotation‑driven airflow with motion‑harvested electrostatic assistance and sub‑ambient thermal management to mitigate traffic‑related particulate matter (PM) and tyre/brake microplastics. Air is entrained through a low‑ΔP cartridge (PMMB/PMM‑style porous media) by venturi/centrifugal channels embedded in the rim; a tribo/piezo energy harvester supplies milliwatts‑to‑watts (speed‑dependent) to bias electrostatic plates and power ultra‑low sensors/telemetry. A passive daytime radiative‑cooling (PDRC) over‑layer stabilizes media moisture/temperature. Prior art supports each element separately (electrostatic tyre‑wear capture at source; rotation‑powered bicycle filters; in‑tire TENG/PEH; flexible PDRC films), but no unified architecture integrates all subsystems in a fieldable rotor. We specify architecture variants for passenger cars, buses/trucks, and rail bogies; define KPIs (power‑per‑speed, volumetric flow, ΔP, thermal margin, PM2.5/microplastic capture); and propose a TRL‑2→4 plan (CFD/FEA → wind‑tunnel mini‑rotor → full‑wheel road trials → rail rig). The concept provides a scalable path to distributed, maintenance‑lite on‑road air micro‑remediation and microplastic abatement, and interoperates with prior PMM/Aqua‑PMMB modules for closed‑loop cartridge servicing and MRV.