“We don’t need to worry,” says Nikolaos Evangeliou at the Norwegian Institute for Air Research, whose team has conducted the first global survey of radiation exposure caused by the meltdown of three nuclear reactors at the Fukushima-Daiichi nuclear plant in Japan after a tsunami struck in 2011.
Even in Japan, the average person’s radiation dose was low: 0.5 millisieverts, which is close to the annual recommended limit for breathing in naturally occurring radon gas.
In comparison, the average annual exposure from background levels of radiation in the UK is around 2.7 millisieverts a year.
Doses were unsurprisingly higher for residents of Fukushima and neighbouring areas during the first three months of the accident, ranging from 1 to 5 millisieverts.
Such doses are still relatively low – a typical CT scan delivers 15 millisieverts, for example, while it takes 1000 millisieverts to cause radiation sickness.
Already, he says, increased levels of radiation around Fukushima have been linked to declines in bird populations there between 2011 and 2014.
Overall, Evangeliou says the hazards posed by fallout from the Chernobyl nuclear accident in Ukraine in 1986 are still much greater than those from Fukushima, because the fallout was larger, and it fell upon more densely populated areas.