Smartphone, Earphone and Bluetooth headsets all emit static magnetic fields as well as RF radiation. A new study found that magnetic fields emitted by smartphones and earphones increased the accumulation of air pollution–derived magnetite nanoparticles in the brain and triggered neurotoxic effects in mice

https://pubs.acs.org/doi/10.1021/acsnano.5c22066

Read more here https://www.ehn.org/bluetooth-earbud-air-pollution-health-effects