asian movie about a smell that kills people

i vaguely remember watching this movie when i was a kid, 3 stories in 1 if i remember correctly but i could be wrong, the story im thinking of is about this really strong smell that just causes people to fall dead. the twist is that at the end of the movie, the protagonist was actually the source of the smell all along. he walks out of a tunnel wearing a space suit (??) and is met with the army ready to shoot at him. confused, he takes off his helmet, and when he does, the smell escapes his suit and kills all the soldiers waiting for him. the movie was asian, im pretty sure it was japanese, but again i could be wrong. it’s eerily similar to the happening except the smell here doesn’t make people kill themselves.