Before revision: Due to the fact that part of the ash of a coal power plant escapes through the smokestack, the radioactive contamination released by coal power plants in regular operation isactually higher than that of nuclear power plants.
After revision: Because a portion from the ash of a coal power plant is discharged through the smokestack, the radioactive contamination released during the regular operation of coal power plants is, in fact, higher than that of nuclear power plants.