Public interest in radioactive aerosols began in the mid-1950s, when world-wide fallout of fission products from bomb tests was first observed. The H-bomb test at Bikini Atoll in 1954 had tragic consequences for the Japanese fisherman, and the inhabitants of the Rongelap Atoll, who were in the path of the fallout. In 1957, radio-iodine and other fission products, released in the accident to the Windscale reactor, were tracked over much of Europe, and these events were repeated on a much larger scale after the Chernobyl accident.

Everyone learns from their mistakes, but, in the nuclear industry, it was also the policy from the start to anticipate trouble by calculating the probable consequences of exposure to radioactive materials. Various pathways of exposure had to be considered, including radiation from radioactive clouds and from fallout on the ground, activity inhaled and activity entering via food chains. Only very limited information was available from actual cases of exposure to radioactive aerosols, and this remains the position today. Almost the only epidemiological evidence is related to the exposure of workers in uranium and other mines to radon and its decay products, and much effort has been devoted to understanding the very difficult dosimetric problems which relate to this exposure. Within the last decade it has been realised that domestic exposure to radon, though lower by order of magnitude than that received by miners, is considerably the most important constituent of the population dose, the radiation dose multiplied by the number of persons receiving it.