I would like to know the ruling on sitting with smokers during the daytime in Ramadan? Does it affect fasting?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

A Muslim must not sit with smokers, particularly if he is fasting, unless that is necessary. If a Muslim must sit with smokers, then he has to observe the obligation of enjoining good and forbidding evil. However, one’s fast is not invalidated by the smell of their smoke since it is unavoidable. Ibn Juzayy, the Maliki scholar, said:

If dust, a fly, or smoke enters through his (the fasting person’s) throat without the person intending so, even if the person is quite aware that he is fasting (not forgetting that), then, according to the scholarly consensus, the person’s fasting is valid since it is too hard for the fasting person to avoid such things. 

Allaah Knows best.