fallout radioactive material

基本解释

refrain from harvesting after radioactive material fallout.
有放射性物质落下时不要进行采收。
Unless a large explosion sends radioactive material high into the atmosphere, most of the fallout from Japan will not make it across the Pacific Ocean.
除非发生了大爆炸，将放射性物质送入高层大气，否则日本产生的放射尘是不会越过太平洋的。
This is highly pertinent. The wind direction, should there be a plume containing radioactive material, determines whether fallout will land on populated areas or in the sea.
这是一个关键问题，如果含有放射物质的云团出现，那么风向将决定这些放射性坠尘会降落在聚居地还是海洋。