Po=POLONIUM
Polonium is a relatively noble metal, similar to silver, but very radioactive. The most stable isotope is the synthetically produced 209Po with a half-life of 103 years. Almost all of the natural occuring Polonium is 210Po with a half-life of only 138 days. This has been used as a short-lived heat source in satellites and as igniter for atomic bombs. It is used in tiny quantities for ionizing air. An average deadly dose of 210Po, when inhaled or swallowed, is one millionth of a gram. A significant dose of polonium 210 occurs in tobacco smoke. Most polonium emerges from radon via strong radioactive isotopes of bismuth and decays further to lead
