3. Was pushed into the stratosphere
Most debris from atmospheric tests of nuclear weapons was pushed into the stratosphere.
Some of the radioactive debris from atmospheric nuclear weapon test lands relatively close. Some stays in the troposphere and are carried by air around the globe, lasting for about a month.
Most debris is pumped into the stratosphere, the next layer of atmosphere (from 5 to 50 km above) where it stays for months, and where it slowly drops backs to the earth.