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

In its early stages the rain was augmented by the small water droplets still descending from the radioactive cloud.

开始时，从放射性云下沉的小水滴使雨势增大。

youdao

In the early morning of April 26th 1986, an explosion at the plant released a radioactive cloud that spread over large swathes of Europe and western Russia.

1986年4月26日清晨，该电站的一次爆炸释放的辐射云蔓延至欧洲及俄罗斯西部长长的一大块地带。

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