core/homeassistant/components/airthings_ble/icons.json

{
  "entity": {
    "sensor": {
      "radon_1day_avg": {
        "default": "mdi:radioactive"
      },
      "radon_longterm_avg": {
        "default": "mdi:radioactive"
      },
      "radon_1day_level": {
        "default": "mdi:radioactive"
      },
      "radon_longterm_level": {
        "default": "mdi:radioactive"
      }
    }
  }
}