The 289 area code was created as an area code overlay for the Mississauga (Streetsville) area. Unlike the previous solutions, this process did not require the place to be geographically separated by different area codes.
Ionizing radiation is a term used for radiation whose quanta have energy to directly or indirectly ionize (one or more electrons are released from the atom of the given substance) molecules or atoms while passing through matter, hence the name ionizing radiation.
There is one other very minor mechanism by which the human body acts as a source of radiation: some of the gamma rays emitted by the radionuclides in the environment interact with the atoms in our bodies by what is known as the photoelectric effect. The result is the emission of x rays by these atoms.