Editing Nuclear fallout (section)

{{Short description|Residual radioactive material following a nuclear blast}}
{{Redirect|Fallout}}
{{Use dmy dates|date=September 2023}}
[[Image:Radiocarbon bomb spike.svg|thumb|right|Atmospheric nuclear weapon tests almost doubled the concentration of radioactive [[Carbon-14|<sup>14</sup>C]] in the [[Northern Hemisphere]] called the [[Bomb pulse]], before levels slowly declined following the [[Partial Test Ban Treaty]].]]
{{nuclear weapons}}
{{Pollution sidebar|Radiation}} 

'''Nuclear fallout''' is  residual radioactive material propelled into the upper atmosphere following a [[nuclear explosion|nuclear blast]], so called because it "falls out" of the sky after the explosion and the [[shock wave]] has passed. It commonly refers to the [[radioactive]] [[dust]] and ash created when a [[nuclear weapon]] explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get [[Entrainment (meteorology)|entrained]] with the products of a [[pyrocumulus]] cloud and when combined with [[precipitation]] falls as [[black rain]] (rain darkened by soot and other particulates), which occurred within 30–40 minutes of the [[atomic bombings of Hiroshima and Nagasaki]].<ref>{{cite Q|Q63214334}}</ref> This radioactive dust, usually consisting of [[fission product]]s mixed with bystanding atoms that are [[neutron activation|neutron-activated by exposure]], is a form of [[radioactive contamination]].<ref>{{Cite web|url=http://www.atomicarchive.com/Effects/effects17.shtml|title=Radioactive Fallout {{!}} Effects of Nuclear Weapons {{!}} atomicarchive.com|website=www.atomicarchive.com|access-date=2016-12-31|archive-date=2018-01-18|archive-url=https://web.archive.org/web/20180118045524/http://www.atomicarchive.com/Effects/effects17.shtml|url-status=live}}</ref>