YOU SAID:

while he's having a smoke

INTO JAPANESE

彼は煙を起こしている間

BACK INTO ENGLISH

While he is causing the smoke

INTO JAPANESE

一方、彼が煙の原因

BACK INTO ENGLISH

On the other hand, he is the cause of the smoke

INTO JAPANESE

その一方で、彼は煙の原因

BACK INTO ENGLISH

On the other hand, he is a cause of smoke

INTO JAPANESE

その一方で、彼は煙の原因

BACK INTO ENGLISH

On the other hand, he is a cause of smoke