Sources of Environmental Magnetite Pollution

All listed options are sources of airborne magnetite nanosphere pollution. Friction in vehicular brake pads (1) and fossil fuel combustion within internal combustion engines (2) release extensive iron-oxide particles. Thermal power generation plants (4) generate these particles through high-temperature coal burning. Household electronic appliances like microwave ovens (3) and electromagnetic fields around communication pathways like telephone lines (5) also yield micro-scale magnetic particles during structural heating or high-voltage operations. > Airborne magnetite nanoparticles are created by both heavy combustion systems and everyday electromechanical friction sources. Answer: (d).