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.
However a large amount of radiation has to be absorbed to get this harmful effect. Radiation can mean a variety of things in the literal sense of the word. The 'radiation' of heat is the process of excited particles colliding with each other to give the sensation of heat. Radiation in the particle sense is the process of a heavy atom (iron or heavier) being too unstable to support its own mass, and therefore it splits itself in to 2 or more smaller atoms.