放射 ほうしゃ せい降下 こうか ぶつでしょう
hōshaseikōka butsudeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 放射性降下物

1. Radioactive fallout, likely.; Probably radioactive fallout.

Polite
Presumptive
Conjecture