<P> In radiation protection , radiation is often separated into two categories , ionizing and non-ionizing , to denote the level of danger posed to humans . Ionization is the process of removing electrons from atoms , leaving two electrically charged particles ( an electron and a positively charged ion ) behind . The negatively charged electrons and positively charged ions created by ionizing radiation may cause damage in living tissue . Basically , a particle is ionizing if its energy is higher than the ionization energy of a typical substance , i.e. , a few eV , and interacts with electrons significantly . </P>
what names are given to the two main types of particle radiation found on earth
ionizing non-ionizing