In addition, isotopes of Pu have been released from fallout. The variability of anthropogenic sources of radiation and radioactivity relates directly to the population distribution and level of technology found in different areas around the world. This type of background refers to both the primary energetic particles of extraterrestrial origin that strike the earth's atmosphere and to the secondary particles generated by their interaction with the atmosphere. Primary radiation itself consists of two components, designated as galactic or solar depending on origin. Primary particles are attenuated in upper atmosphere.
Reactions take place and generate secondary particles.
The latitude effect is due to the charged-particle nature of the primary cosmic rays. 12,200 Spy plane Adapted from Gollnick 1988 . Cosmogenic Radiation Cosmogenic radionuclides arise from the collision of highly energetic cosmic ray particles with stable elements in the atmosphere and in the ground. The entire geosphere, the atmosphere, and all parts of the earth that directly exchange material with the atmosphere contain cosmogenic radionuclides. The major production of cosmogenic radionuclides results from the interaction of cosmic rays with atmospheric gases.