How was one [living in France] supposed to know whether or not to worry about a radioactive cloud?

怎能知道，[在法国生活]的人们应不应该为放射性尘埃担心呢？

youdao

That is why they drove straight into the radioactive cloud.

ECONOMIST: Banyan

In 1986, the fourth reactor at the Chernobyl nuclear complex in the Ukraine exploded and caught fire, spreading a radioactive cloud across Europe in the world's worst nuclear disaster.

CNN: Saturday,

The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap.

ECONOMIST: Antihydrogen atoms are captured for the first time