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.
About 80% of the sources that contribute to the ionizing radiation exposure dose on humans originate from natural radioactivity. The natural sources are part of the terrestrial environment and include the isotopes of the ground of the Earth and the cosmic radiation, which is being emitted by the Sun and other stellar sources in deep space.